the dealers` guide to chemical restoration of postage stamps
Transcription
the dealers` guide to chemical restoration of postage stamps
THE DEALERS' GUIDE TO CHEMICAL RESTORATION OF POSTAGE STAMPS PREFACE It is the purpose of this guide to provide the Stamp Dealers (in fact the entire collecting body) with Information on the basic, yet simplified techniques of philatelic chemistry, so that they may be cognizant of the means by which they may improved the appearance of those stamps which may be stained in their own private collection. When a collector or dealer, äs it may be, purchases a stamp for his collection, the stamp may have acquired certain unattractive blemishes, stains, accretions or other extraneous material which is displeasing to the philatelists eye when presented within a collection. To improve the value of a collection by methodically purchasing stamps of pristine quality is a constant aim of every true collector. While the dealer is in an advantageous position to do so, he is often confronted with the most difficult decision; to purchase the unused stamp free of stains, or to purchase the mint stamp with stains. Only the auctioneer knows the consequences of this decision on the bidding floor. The dealer concentrates on the margins, centering andperforations with additional emphasis on the freshness of the stamp. His preliminary examination is followed up by dose examination under ultra violet rays. Almost every fault that is embodied within the stamp, invisibly, will show either under The Lamp or within The Juice. Crossing into this Region ofthe Unknown, we are faced with a complex judgement: ignorance is bliss! Were a collector or dealer to lamper with the very fibers of the stamp 's body for the purpose of monetary gain, he certainly would be misinterpreting the condition of that stamp, since he altered the physical structure of the fibers in an attempt to increase it's value. In effect, he affected the body of the stamp by synthesizing the fiber work. Conversely, it is not considered unethical to approve the appearance of a stamp by discharging gum or dirt in boiling water, by discharging grease stains in benzene or carbon tetrachloride, or by restoring colour on sulphuretted stamps with dilute hydrogen peroxide. When the Philatelist dips a stamp in water mark fluid in an attempt to observe the water mark, whatever eise he does, he is in fact cleaning the stamp. This universally accepted treatment of stamps does clean, restore, freshen, remove and loosen many stains and extraneous materials. This "juice" äs it is referred to is but one of many reagents which can remove many unsightly stains that have occurred over long periods of time, or by careless handling of liquids and other foreign materials. Such are displeasing to the collectors natural desire to honour the Vignette which he presents on his album page. Decades of mishandling, exposure to the elements, sulphuration, oxidation, fingertip oll discolouration or the likes, frustrate the Dealer Collector's attempts to compile stain free material. Very simply, to restore the face of a stamp which has been in advertently marred by stain, for the purpose of enhancing the very spirit of collecting, is no more harmfui to the profession than soaking or dipping or dehinging. It is not the intent of this Guide to provide means to fraudulently misrepresent the actual condition of a stamp which might later be so/, since any attempt to do so would be in violation of the code of ethics, and the principle and fundamentals of the Philatelie Societies and Associations. In fact, no material presented herein is intended for the illegal removal of cancellations, overprints of surcharges, orcolour changelings of stamps. Any attempt to relate such shall be misconstrued and in violation of Federal Statutes and subject to the penalties äs stated under the provisions of the Treasury Department. RESTORATION When we speak of "cleaning" we refer to that process by which a stain or foreign material has beert removed by chemical or other means. Often, cleaning is readily apparent on dose visual examination, or under the illuminated magnifying glass because of a slight colour change or disturbance of the ink of the design or the paper. The cleaned area can readily be detected under the Ultra Violet Lamp, since those areas cleaned will appear to be whiter than the surrounding area which was left untouched. Provided, ofcourse that the entire stamp was not immersed in the reagent. CHANGELING when referred to colour, designates a stamp whose colour has undergone a transformation, usually permanently, to another colour. This happens because of prolonged exposure to light or because the stamp has been placed in a liquid to affect the change. Bleaching is a process by which a colour is chemically destroyed by oxidation either by over exposure to light or by continued Immersion in benzene, peroxide or hydrogen, carbon tetrachloride or trichloroethylene. Since the entire concept of restoration depends upon so many factors we must caution the experimenter on a most important subject, that of fugitive colours. Many inks cannot tolerate any Immersion whatsoever, not even in water. While the knowledgeable dealer and collector know of the colour running problem with carbon tetrachloride, tnchloroethylene and benzene, he is faced with the problem of which inks are fugitive in these reagents and which are fugitive in water. Unfortunately, there is no hard fast rule or list which encompasses those stamps except to say that no photogravure stamps can stand an Immersion in these substances at all, nor can coated papers. Deoxidation is synonymous with Sulphuration (Sulpheretted) and is offen misinterpreted with oxidation. A sulphuretted stamp is one in which the lead in one of the ink constituents has combined chemically with the sulphur in the atmosphere. This causes the original colour (usually blue, green, read oryel/ow) to become a brownish black colour. Salt ocean water can offen achieve sulphuration. TO WET OR NOT TO WET While we are trying to acquaint the dealer-collection with the various techniques for neutralizing stains with various Chemicals, it must be understood that one must weigh the merits of pursuing the various procedures. The ultimate answer is to proceed on a damaged duplicate to ascertain whether the ink and the paper can survive the chemical treatment. It must be emphasized that no guarantee is either stated or implied that a particular chemical, treatment or serious of treatments will work each time, in fact work at all, due to the nature of the beast. The inks, the papers, the printing processes employed, the adhesives, the condition of the aged paper and stain, the actual fragility of the stamp itself, the degree to which the stain has permeated the paper and ink; all of these factors coupled with the intensity of the staining body dictate delicate Implementation ofeven the weakest chemical. Restoration itself should be implemented only äs a last resort when the gravity of the Situation is weighed. One must consider the time and expense involved, and the possibility of ending up with a perfectly bleached, beautifully cleaned, perforated white square. However careful the experimenter is, he must closely watch the progress of the reaction and determine when and if the reaction is complete enough without rendering the stamp useless. On occasion, one must repeat certain processes to complete remove the stain, but at the same time watching that this repetition does not completely weaken the ink and paper. When the cleaning process is äs complete äs possible, each stamp must be thoroughly washed to remove all traces of the catalytic chemical. Before the person has decided to attempt any procedure with a mint stamp, he must, in his own judgement, decide whether the stains stays, or the gum does. It must be remembered that in some cases a few moments of careful examination could allay any chemical treatment at all. If there are light pencil marks on the face of the stamp, it would be wiser to use a delicate soft gum eraser or the dough from a frozen roll mix than chemical washing. Generally speaking, if the chemical employed can remove the stain, it may also be able to remove the ink and destroy the stamp. The mildest treatment possible should be employed betöre attempting stain removal with the more sophisticated chemical reagents. Even then, solution of the chemicals ought to be considered even if they must be repeated several times, for we cannot undo in minutes what nature has spent years achieving. Whenever water is to be used, always use distilled water or, if available, sterile Water for Irrigation which is available in 1500 ml Containers. It is quite inexpensive and is chlorine and chemical free. Certainly, if water can do the Job alone, it should be considered even if it prolongs the final results being achieved. In some instances combination procedures can be alternated to achieve final results. Perhaps water, then a solvent, than a mild bleach, then water again. TESTING THESTAMPS WATER SOLUBLEFACTOR AND EMPLOYING VARIOUS TECHNIQUES Using a piece of acid free filier paper, one can usually determine the solubility of a stamp's ink. By moistening the filter paper slightly and then proceeding to place it against the stamp's face for a moment, one can usually spot a slight semblance of colour transferred to the filter paper if the ink is fugitive. If, at this point, the restoration must be continued, the chemical or water can be applied minutely from the back of the stamp, possibly with a glass square being placed atop the face of the tamp, or by placing filter paper (ACID FREE) either above or below the stamp depending on whetheryou are working on the face or attempting removal from beneath. An alternative method would be to place the tamp and chemical within the various stamp sweat boxes available, being careful; not to use any chemical which might be corrosive to the plastic of the box itself. A fine spray atomizer can be purchased quite inexpensively and would offer a finer, more controlled method of applying the solution. If the decision is made to attack the stain face forward because of the thickness of it, you should have several degrees of fine artists natural säble brushes, the best you can find. Be particularly careful not to let the solvents attack the plast/c or paint portions of the brush or you may end up having removed one stain only to find another more difficult one. It is suggested that howeveryou störe your assortment of chemicals, the Container be amber coloured to prevent breaking down of the chemical itself. Many chemicals will lose their potency when exposed to even slight amounts of normal light. They must be tightly stopper, kept away from heat or cold, and usedpreferably In well ventilated areas. Because you may be interchanging many chemicals and procedures, keep all chemicals away from open flames and sparks. Never use the same device to apply different chemicals since this may neutralize one of the chemicals over a period of time by contamination. We suggest storage within amber, light proof 15 or 30 m glass applicator bottles. APPLIED DETECTION As we mentioned earlier, it is offen possible to detect chemical cleaning on a stamp with the use of Ultraviolet rays. We feel it important to make the dealer-collector aware that no restoration goes entirely undetected and for that reason include a brief dissertation on the applied use of Ultraviolet äs related to restorative detection. In order that this be accomplished we must ask the more knowledgeable Philatelist to retrace whatever Information is provided within this text, that others might learn. Since its discovery, Ultraviolet has intensified the dealers' and collectors' search for distinguishing characteristics in the form of faults, forgeries, erasures, bleaching, dyeing and more recently tagged and untagged errors on the postage stamps of the world. This has enabled him to determine the true market value of an otherwise seemingly unsuspected stamp. Whether the stamp has been tampered with or not is more visible under these rays when the trained eye can realize what is confronting it. The purpose of this guide is to brief the collector on what to expect with Ultraviolet; his patience and experimentation will eventually make him expertise in his judgement. It is to this end that we point out what has already been learned with Ultraviolet in the realm of philately. It is important at this point to note that the unit should be handled with extreme caution so äs not to expose the eyes to short wave ultraviolet, äs it can severely sunburn the corneas. Although it is well known that eye glasses will stop short wave ultraviolet it is possible for the rays to enter the unprotected areas around the glasses and thus injure the eyes. Never stare directly into the lamp nor point it towards another person or a reflective surface. PHILA TELIC APPLICA TIONS Ultraviolet lamps are extremely useful in the detection of normal departures from the ordinary on the paper or ink of stamps, such äs repairs and forgeries, because the fluorescence which eminates from a portion of the stamp which has been altered will show a marked difference from that of the original paper. Examples of this would be mends, erasures alterations, spot bleaching, cancellation removal, colour removal, cleaning, restorations, forgeries, dyeing, comparative fluorescence, aura diffusion, eradications, gum changes, tagged and untagged errors, coding, American and National bank note paper differentiation, margin addition, thinning replacement and shading. As we have seen, the main purpose of ultravidet is to provide Information on a stamp which may not be obtained by other methods. Obviously, if differentiation is usually is accomplished by reflected radiation and depends upon the premise that two or more portions of a stamp will reflect orabsorb ultraviolet to different degrees. Some inks will absorb ultraviolet while others will reflect these radiations. Some have partial absorbtion and partial reflection. These effects can be recorded photographically by using ultraviolet radiation. ULTRA VIOLET RADIATION A complete ränge of electromagnetic radiation extends from the extremely short wave lengths ofgamma and x-rays to the extremely long wave lengths which comprise the radio bands. The visible spectrum is included in this ränge and contains a narrow bank of radiation from about 400 nanometers to 700 nanometers in wave length. Another narrow band of radiation is also included in the complete spectrum and is comprised of shorter wave lengths than the visible. This is the band of ultraviolet radiation, extending from about 10 nanometers in wave length to 440 nanometers, the Iower limit of the visible spectrum. Ultraviolet can not be seen by the normal human eye and is often termed "invisible" äs are all other electromagnetic radiations except those in the short visible ränge. By using a filter that absorbs all visible light but passes ultraviolet, it is possible to make a photographic exposure with just ultraviolet. This technique is called ultraviolet photography. TYPES OF ULTRAVIOLET For practical purposes the ultraviolet spectrum is divided into three very narrow bands: long wave ultraviolet, middle ultraviolet, short wage ultraviolet. Another band, called vacuum ultraviolet, also exists but is of no concern for our particular purpose. SPECIFIC APPLICATIONS Although the practical applications of ultraviolet for our purposes appear to be few, the mastering of this technique can be defined äs advantageous and profitable. Suspected alterations or additions might be made visible only by the use of ultraviolet. Also, faded stamps can often be made more legible through ultraviolet since the faded ink may be brought out in contrast to the paper. This is particular true with erasures. LUMINESCENCE When certain materials are subjected to short wage electromagnetic radiation, they will emit another radiation of longer wave length and, very often, in the visible spectrum. This phenomenon of induced light emission is called luminescence. There are two distinct types: fluorescence and phosphorescence. 8 FLUORESCENCE If the luminescence ceases within a very short time after the existing radiation is removed, the phenomenon is dissipated. This phenomenon is called fluorescence. Although fluorescence is commonly produced by excitation with ultraviolet energy, it is also possible to stimulate with some visible wave lengths. PHOSPHORESCENCE Although fluorescence ceases almost immediately after the exciting radiation is removed, there are some substances which continue to emit luminescence for some time. This phenomenon is called phosphorescence and is produced in dyes called phosphors. Since there are many dyes which exhibit fluorescence when excited, this is the basis of applications in philately necessary to supply Information that cannot be obtained by other means. Just the fact that a substance does not fluoresce is enough to differentiate it from which one does not. When two substances both fluoresce they may differ in colour. Fluorescence can occur, however, in long wave ultraviolet with short wave ultraviolet excitation. It can also occur in the long wave visible region with blue light excitation. Many inks show a difference in visible fluorescence. The effects of bleaching or erasures can be detected by this means. Some papers on which cancellations are made contain cellulose fibers. These divers offen fluoresce brightly when the paper is illuminated by ultraviolet in a darkened room. After this exposure, erasures will fluoresce. If inks have been bleached - äs with an eradicator - the bleached material still in the paper may show a typical fluorescent colour. It should be noted that another form of luminescence does exist which may be of some importance to philately. This is the realm of infra-red luminescence. Although must luminescence appears in the visible spectrum and is excited by either ultraviolet or visible short wave lengths of blue, it is also possible to excite luminescence in the infra-red by Irradiation of certain stamps with blue green light. The phenomenon referred to is luminescence instead of fluorescence or phosphorescence because it is not known if the effect ceases immediately after The exciting Stimulus is removed. When two portions do fluoresce, they may differ in colour. Most fluorescence occurs in the visible spectrum with longwave ultraviolet excitation. Fluorescence can also occur in long wave ultraviolet excitation. 11 can also occur in the long wave visible region with blue light excitation. Different inks may show different luminescence when irradiated with invisible blue green light. This may prove invaluable when detecting alterations. Since the fluorescence given off by any part of a stamp which has been tampered with will differ from that of the original portion, we can see why erased cancellations including pen marks show up clearly äs do added margins, fil/ed in thinnings and painted-in designs. Ultraviolet is also useful in shade recognition. Example: the rate Great Briton 6d., bright magenta of Edward VII, or the 1/2 d Cyprus green of George V can be recognized immediately by their golden glow, which is completely absent from other less valuable stamps. Whatever is observed under the rays are not answers themselves since these answers must give in to individual Interpretation. ULTRAVIOLET FILTER All lamps which emit ultraviolet light also emit visible light which tends to make any fluorescence that is occurring. Therefore, it is necessary to place in front of the bulb a dark purple glass filter which will block äs much of the visible light äs possible but will, at the same time, transmit the ultraviolet. Several types of dark blue or purple glass can be used äs a filter on a long wave lamp. Sometimes the long wave bulb itself will be made from a dark blue glass that acts äs a filter. However, a filter for a short wave lamp must be made from a very special kind of glass, since äs we have already seen, the short wave radiations will not pass through ordinary glass. FLUORESCENT POSTAL STAMPS While the tagged stamps are all fluorescent under shortwave ultraviolet, we speak here of the fluorescent stamps which have been printed with fluorescent inks. While there is a new interest in fluorescent stamps, they are not new, having been issued 10 through the years by many countries. They date back to the 1800s and perhaps earlier. The characteristic of these stamps is that they glow in bright colours under an ultravio/et source. They will usually react under either longwave ultraviolet or shortwave ultraviolet, whereas the tagged stamps react to shortwave ultraviolet only. An example of a spectacular, brilliantly fluorescent stamp is the German Dove of Peace 1 mark stamp. This stamp is a drab olive green in ordinary light, but under longwave ultraviolet it glows a brilliant green showing the Dove of Peace in attractive non fluorescent contrast. An interesting point offen observed when examining stamps under ultraviolet is the variations in fluorescence of the paper on which the stamps are printed. Very old papers show for the most part little of any fluorescence, while modern papers vary from non-fluorescence to brilliant btue-white fluorescence which is best observed in longwave ultraviolet. It is common for the same issue of stamps to appear printed both on fluorescent and non fluorescent paper. As pointed out previous, the US 4 cent Lincoln stamp not only appears äs a tagged stamp but also in untagged varieties both on fluorescent and non fluorescent papers. The variations in fluorescence commonly found in appears can be vividly illustrated by shining a longwave ultraviolet source on a random group of envelopes. Some will appear a dull purple, while others will fluoresce in various degrees ranging to a brilliant bluewhite. The reason so many modern papers are fluorescent is that during their manufacture they are brightened by the addition of what is k known äs an "Optical bleach", These so called bleaches do not actually bleach the paper but cause a blue fluorescence which is activated by the ultraviolet present in sunlight and in most artificial light sources. Fluorescent optical bleaches are almost universally found in household detergents used for the washing of clothes. 11 POSTAL STAMP FORGERIES AND ALTERATIONS Since ultra violet will reveal many differences in materials not seen in visible light, it can frequently be used to detect repairs, alternations and forgeries. Radly and Grant* report a number of interesting examples of such detection, One case mentioned is that of a very valuable Ceylon stamp on which the users frequently clipped the corners in an effort to make the stamp more attractive. Repairs have at times been made to restore these stamps. However in ultraviolet the replaced corners are readily detected by their difference in fluorescence from the original center. Other imitations recorded include a forgery of a 1/4" such. Holstein stamp of 1864 in which the ink fluoresced clue, while the original did not react at all to the ultraviolet. An Imitation of a Baden number 1 issue obtained by dyeing a number 5 issue was readily detected under ultraviolet, since it appeared much lighter in colour than the genuine stamp. A more recent counterfeit, readily detected under ultraviolet, is the Ryukyu Islands overprint Scotts #16. Under ultraviolet the genuine overprints show the ink äs brown-black in appearance with a slight aura caused by diffusion in to the paper of the oil from the printing ink. The counterfeit overprints have a blue-black appearance and do not show the aura. Eradications, erasures and gum changes are all liable to leave fluorescent evidence which may be completely undiscernable in visible light. The possibilities are limited only by the ingenuity and curiosity of the investigator. DETERMIN A TION OF FA UL TS Since we have already learned that the ultraviolet rays will cause a differentiation because of allen paper, orfaults such äs tears, one has but to scan a particular stamp for any white dots or spots which are indicative of foreign paper being added to fill in a hole or tear. Since any disarrangement of the fiber of the paper will appear under the "lamp" äs fluorescing differently than its surrounding media, we can make observations about the quality of the stamp we are buying 12 THE NATIONAL AND AMERICAN BANK NOTE PAPERS Most collectors are aware of the hard papers of the National and Continental Companies and the soft papers of the American Bank Note Company. In most instances these papers can be recognised by their physical characteristics äs described in various philatelic references. The stamps can be illuminated on the printed side of the back side and one can use the long or the short wave, or both, to show the differences. linder the ultraviolet light the hard papers appear rather white in colour and the soft papers appear tan in colour, and duller in appearance and the collector has no problem in separating the two types of paper. It is true that hinge remnants and paper defects can interfere with this differentiation when one illuminates the back side of the stamp, but one should be able to identify the type on one side or the other. The best procedure would be to identify the type on one side or the other. The best procedure would be to identify the stamps on the basis of their physical characteristics and then verify your findings with the ultraviolet light. With both wave lengths turned on the National (hardpaper) will appear lighter and brighter and whiter than the American Bank Notes (soft paper). The soft paper stamps are duller; they reflect the light flatly and appear tan in colour. SAFETYPAPER This is a comprehensive term used to designate any special paper of which the object was to precent cleaning and reuse of used stamps. There are many different varieties of safety papers, such äs "chalk surfaced", "Duples", "Enamelled" and "Silk Thread". They include for example: Austria 1901-02 - paper printed with diagonal bars of shiny varnish. Benzine or petroleum will sometimes affect some inks by dissolving part of one or more of the constituents. Offen such treatment will visibly affect the stamp to a large extent by suffusing the paper with colour that has run; but sometimes the visual change is slight, and it is only when the tamp is examined by ultra violet rays that a dramatic effect is observed: the stamp that has been immersed in benzene or petroleum fluoresces brightly, while an untreated example of the same stamp does not f/uoresce to anything like the same extent. It is important to 13 bear this fact in mind, because some philatelists have wrongly accepted äs axiomatic, that marked difference in fluorescence inevitably points to the use of inks of different compositions, and, therefore, to be incontrovertible evidence of a new or different printing. PROGNOSIS The tools of technical philately, having been made available, can be used over and over again on äs many copies of the same stamp äs can be obtained by one collector. It does not necessarily follow that to have examined one stamp once, no further discoveries can be made. For äs the collector becomes his own expert in judging what he sees, he must not convince himself that no further discovery can be made. There are of course, additional, highly sophisticated methods of detecting stain removal and we shall note them only briefly. With the use of Isotope Bambardment and the subsequent spectrographic analysis, it is possible to detect the removal of a complete colour from a stamp. Another method of detection is to use the high magnification dry watermark comparator on the market which utilizes Intensifiers. When the suspect stamp is placed within the intensifiers, along with a reputable one, the very body of the stamp is laid open so that every fiber of the paper in fact the entire inferior of the stamp appears äs if illuminated from within. By careful examination of the printed portion of the stamp, one may be able to detect those random areas which have been cleaned. The paper appears to have unnatural white areas in contrast to the natural thins which appear quite noticeable in deference to any watermark which may or may not be prevalent. With the advent ofcoloured filters, these areas become even more pronounced. This method is quite necessary for those stamps in which immersion is prohibited, or where magnification is more important than Ultraviolet. As for chlorine detection, quite simply, a keen sense of smell can detect those stamps which have undergone this treatment. 14 ASEPTIC TECHNIQUE In each phase of the restoration, it must be kept in mind that we are dealing with a fragile piece of paper, which comes even more fragile when wetted. Any device at all which can support the stamp within a tray is better than handling with either stamp tongs or fingers. Chemically pure reagents are absolutely necessary, since most over the counter prepared chemicals contain impurities which can interfere with the reactions. DIRT AND DIFIT RELATED STAINS Perhaps the easiest to remove, dirt requires no specialized solvents to effect its' removal. Quite offen dirt can be removed by merely ringing the stamp in cold water. It may be necessary to place several drops of ammonia in the water. If water or a soff gm eraser does not work, add a small amount ofcastile shampoo and work up a lather. If the dirt is very firm add some Flo to the water before adding the soap. Flo will Iower the surface tension of the dirt and make it more responsive to the soap. The stamp should be thoroughly rinsed after treatment. The brush tip should be swept across the stamp in broad even strokes. BLOOD STAINS Wet the stamp thoroughly. Prepare a warm solution of Degest (proteolytic enzyme) and soak the stamp in it for about 30 minutes. Using a mild castile wash, gently stroke the area with the säble brush until the area is clean. Rinse the area thoroughly until all matter has dissipated. Be sure to stabilize the stamp within the tray so that the brush strokes can be made evenly and smoothly. EGG STAINS Prepare the stamp by thoroughly wetting with a solution of mild castile and Flow. Add a small amount of warm Degest solution and work up a later. Lei the stamp soak and repeat the process several times. When the Degest has done its' work, rinse the stamp with more Flo and water quite well. Rinse completely for several minutes. 15 STAMP ADHESIVES Prepare a solution of .1% sodium Chloride and 10% acetic acid. Remove äs much of the paper äs possible and lay the stamp upon the acetic acid solution being careful to keep the top of the tamp above the surface of the liquid. With a sharp pointed blade (hobby type) remove any paper or hinge material layer by layer, from the back of the stamp. Now repeat the soaking process, stamp face up until the adhesive is sufficiently softened. Gently brush away the adhesive and rinse well. If another application is required, add a small amount of Flo to the final rinse. Brush evenly and rinse well. If the stamp colour is known to be fugitive, use the solution in a fine atomizer and spray only on the back of the stamp. Continued spraying and alternative peeling with this method will be longer, but the results will be more satisfactory. A well lighted magnifier will be quite helpful in preventing the knife blade from cutting too deeply into the paper of the stamp. STAMPS AND SELF-STICKING ADHESIVES For the past third of a Century various seif sticking material have appealed to stamp and other collectors by their readiness and ease of use. However, time has almost always brought stains to, and/or welding together or the materials involved, with accompanying trouble and loss for the owner thereof. Complaints have come from collectors for manyyears bewailing the damage caused to stamps resulting from the use of self-sticking tape. The older the original application of the tape to the stamp, the more severe has been the damage to it. This investigation was undertaken to determine, if possible, the cause for the damage incurred and what could be done to salvage the injured items. 16 The adhesives on self-sticking tapes belong to that class of compounds known äs polymers. These polymers are found in the adhesives on masking tape, transparent tape, some mending tapes, and on self-sticking labels. The question is then asked: "What are polymers?" The word is derived from the Green. "Poly" means many, "mer" means parts. Hence a polymer is a chemical compound having many parts. In ehernistry we have many compounds which are capable of reacting with themselves repeatedly to form /arge entities (molecules) in the following manner: 10 equals A-A-A-A-A-A-A-A-A-A The starting compound "A" is a monomer (one part) and the product formed is a polymer. Many kinds of polymers exist. We encounter them offen in every day life. Some common examples are wood (cellulose), and of course, plastics. The organic chemist has learned to make many polymers for our daily use. Well known examples are nylon, polystyrene, dacron, lucite, bakelite etc. A special class of polymers has the unusual property of being sticky and elastic. This class is called "elastomers". They are the main component of the adhesive on self-stick tape, hinges and labels. Many elastomers are known and used in the rubber industry. > Common examples are neoprene, natural rubber, Natsyn, BunaS, Hycar, Viton etc. Examination of a first day cover dated August, 30 1934 (37 Vz years old!) which had been mounted in an album with seif sticking tape revealed that the adhesive had darkened to a deep brown colour and had so dried along the edges so äs to Start to peel away 17. The discolouration had penetrated the envelope until the colour was visible on the inside surface. This is an extreme example of what can happen when this tape is used. Another group of stamps examined which had also been mounted with self-stick tape (brand and date unknown) appeared much like the above samples with the exception that the adhesive was much hardened and more brittle. While this difference could be due to a difference in paper, a different adhesive is more likely. In both of the above examples the backing tape was transparent. Apparently with time three distinctly different changes slowly take place on the stamp mounted with such adhesive 1. A darkening, probably due to oxidation of the adhesive by the oxygen of the a/r. 2. A continuation of the polymerization process leading to a stronger bond between the stamp and the hinge, and between the hinge and the album paper. 3. A loss of plasticizer. Plasticizers are liquids of Iow volatility which are offen added to polymers and which aid in keeping the polymer soff and pliable. A common example of a plasticizer is the use of neatsfoot oil on leather. The oil keeps the leather soff and pliable. The loss of plasticizer could be the result ofslow evaporation, or might be due to stow absorption by the paper, or both. As this point a number of factors are apparent: A) It is usually impossible chemically to reverse in a short time a change that has required 10-20 years to bring about. B) Any method adopted for the removal of the adhesive must not allow the discolouration to spread throughout the stamp. 18 C) the process to be used should be capable of penetrating both stamps and album pages and remove the discolouration which ahs penetrated the paper, A method that satisfies the requirements is often used by the organic chemist and is called "continuous extraction". The procedure has the advantage that solvents can be changed readily during a study of the solubilizing power of various solvents. It can be operated continuously for days if necessary. The process can be described briefly äs one of a continuous and repeated soaking of the material in hot solvent followed by complete removal of the solvent. When the cycle is repeated the apparatus automatically uses fresh solvent. 1. The discolouration and the hinger can be completely removed from both stamp and album sheet (or mount) when Scotch tape has been used. This is type A. 2. Type B solvents will completely remove discolouration and adhesive from hinged and used stamps, but not from the gum on some mint stamps. Forsome obscure reason the discolouration clings very tenaciously to the gum. Both the latter and the discolouration are completely removed when the stamp is soaked in water. This tape has all of the outward appearance of the usual tape of this class. 3. The seif stick tapes belonging to this third type must be a recent development, and insufficient time has elapsed to reveal its true characteristics. No discolouration was detectable on either the stamp or album page on the samples submitted. 19 The hinge is impossible to remove without either tearing or peeling the stamp or atbum page. The adhesive will require different solvents from those used on types A and B. During the treatment the adhesive swells but does not dissolve easily. The stamp should be removed at this stage and the hinge carefully peeled off the stamp. The softened and swollen adhesive is then carefully rubbed off with a wad of cotton and the stamp returned to the extractor for an additional six to 10 hours of extraction with solvents, to effect the complete removal of the adhesive from the stamp. The backing on this group, Type C, has a translucent rather than transparent appearance. While l was aware of the dangers encountered with some stamps when watermark testing with organic solvents, l was truly dumbfounded to discover what does happen to a limited number of stamps (thank heavens) when subjected to exhaustive extraction with organic solvents. Some stamps will lose all colour to form albinos, while others will lose only a pigment component to give new and unusual, and even startling, colour changes! Regretfully such stamps will be lost for good. The removal of seif sticking hinges and tapes, and ofthe resulting stains will require prolonged treatment with solvents. Let us repeat again, one cannot undo in a short time what has taken years to bring about. The solvent treatment must not spread the stain throughout the paper. We accordingly are forced to use a process of continuous extraction whereby the used solvent is replaced b y fresh clean solvent. An apparatus which does this efficiently is a Soxhlet extractor illustrated in Figure 1. 20 The vapours of boiled solvent in flask "A" rise through side tube "B" to the condenser "C". This condenser cools the vapours and the liquid drops into the reservoir "D". This reservoir will contain the stamps to be cleaned. The reservoir fills with the Condensed liquid to the level of the siphon "E" whereupon all liquid overflows back into flask "A". Upon continued heating the process is repeated. The Condensed liquid again fills the reservoir and is again siphoned back into flask "A". All soluble material (adhesive) on the stamp is thus slowly dissolved off. Obviously the process is automatic and may be continued äs long äs it may be necessary. Now forsome precautions, and observations: All self-stick hinges and tapes can be removed, completely. Stains on used stamps and on paper can be also completely removed. Stains on gum sometimes cannot be removed but disappear with water upon soaking. The time required for the removal of the stain will depend upon the porosity of the stained paper. The denser the paper the longer will be the time required. The duration of the treatment will average about 32 hours, but refractory cases will require up to 60 hours of continuous treatment. The backing of the hinge or tape will act äs a barrier to the solvent which slows down the removal ofthe adhesive. Removal of the stamp after about 8 hours of treatment and peeling off of the hinge, then continuing the treatment will materially shorten the time necessary for the removal of the stamp. 21 The dissolved pari of the adhesive is very soluble in the solvent. The first few cycles of the extraction process will be highly coloured. Solents to use: When the tape or backing is transparent benzEne is the solvent of choice although toluene will also be effective, to a somewhat lesser degree. NOTE that this is benzENE and not benzlNE. BenzlNE will not be effective. Technical grades of benzene and toluene are sold äs Benzol and Toluol. These have not been refined and may contain constituents which may härm some stamps. Use chemically pure or reagent grades of solvent. When the backing of the tape or hinge is translucent but not transparent, and the adhesive is not discoloured, the solvent to use is methyl-ethyl-ketone, although acetone will work, but more slowly. (Again the flammability and toxicity warning!) 11 is imperative that the hinge be peeled off after it has been softened (5-10 hours) and the adhesive be wiped off with a wad of cotton betöre continuing the treatment for completing the removal of adhesive from the paper. Now for the precautions: The vapours of organic solvents are flammable and toxic! The vapours of benzene are especially so. Accordingly, the extraction should be done in a fire proof room. All handling of the solvent-soaked stamps should be done in a fume chamber or hood where the fumes are removed by an a/r draft. This is not an Operation to be carried out by the amateur; have a chemist do this for you. 22 Those stamps which contain dyes and pigments soluble in organic solents will have these colours removed by this procedure. We will then have the Situation where "the Operation was a success, but the patient died!" In those instances where documents and album sheets must be treated äs above, a modified Soxhlet must be used. Diagram of the Soxhlet extractor. Note that there is no entrance only an exit -in the bottom of the reservoir in which stamps are treated -H 23 F'ATAND RELATED GFIEASE STAINS Prepare the stamp within the tray by applying a light coating of morpholene. Work well in to the stamp until the entire area is covered. With a second brush, apply thin even strokes ofpyridine, repeating the process several times. Rinse the stamp well with soap wash (castile and water). Rinse again with cold water. If it is necessary to repeat the process Start with warm glycerin, applying even strokes. Follow this with benzene. Wait several seconds and repeat the application of the glycerin. Now apply broad stokes of benzine (not benzene) fairly rapidly. Remove all solvente with the soap wash and rinse well with cold water. NON GREASY STAINS Place the stamp in the tray and apply a small layer of mineral oil to the stained area. Wait several seconds and apply a thin layer of amyl acetate using fast brisk brush movements. Wait several moments and wash with castile and then cold water. Repeat the process, washing thoroughly. If this falls use pine oil first, saturating the stamp well. Then apply acetone since it can solubilize mosi inks. Rinse well with castile wash and plenty of cold water. Flo should be used in all rinses containing stains that are difficult to remove. SCOTCH TAPEADHESIVE Thoroughly saturate the stamp with carbon tetrachloride and work the tip of the brush back and fort/? at first, then in a circular motion. Remove the stamp and while it is trying, sweep a dry brush across the area until the "Juice" dissipates. Repeat the process several times, keeping the stamp in the liquid at a minimum. A castile wash with Tween 20, followed by a clean rinse is advised 24. AIRPLANE GLUE Soak the stamp first in pyridine then in amyl acetate. Dry stamp completely. Apply a thin layer of mineral oil and repeat the process, brisk/y brushing the area. Rinse well with Flo and water until all extraneous material is removed. SEALING WAX ADHESIVE Apply a moderate amount of morpholene and thoroughly moisten the area with 91% isopropyl or ethyl alcohol. Wait several minutes before using the alcohol. Wash with more alcohol and follow with a castile wash. Use rapid strokes with the brush. Follow with a bath of Flo and rinse thoroughly. OIL PAINT SPOTS Soffen the stain with pine oil and wait several minutes. Apply tetraethylene for about 30 seconds and repeat the process. Wash with castile and remove all traces with Flo and cold water rinse. Repeat the process substituting heptaner or hexane for the tetraethylene. TAR Prepare the stain with ineral oil and allow to stand for 1 minute. Gently brush naphta until all tar is removed. Use a castile rinse which incorporates afew drops of Tween 20. Rinse with cold water and Flo. Rinse again with water. TOBACCO STAINS Apply warm glycerin to the area to be treated. Brush 91% isopropyl or ethyl alcohol on freely for several seconds. If this falls, dip the stamp in 10% citric acid for 1 minute and then follow the same procedure. Thoroughly wash and rinse the stamp with cold water. Use a Flo rinse. Wash all traces of sediment away with tepid water. 25 CANDLE WAX STAINS Immerse the stamp in carbon tetrachloride and brush freely for several seconds. Allow the stamp to a/r dry. Repeat the procedure until all of the wax is reduced. Repeat and brush smoothly while still immersed. Allow to a/r dry and wash (if colour is fast) with a Tween 80 rinse and castile bath. Rinse completely with cold water. ADHESIVE TAPEADHESIVE While stamp is in ray, brush swiftyl with naphtha and follow with castile and Tween 20 wash. Repeat process and rinse well with cold water brushing with a clean brush You may use a Flo in the next to final rinse. CRAYON STAINS Soffen the crayon with pine o/V for several minutes and apply smooth strokes of naphta. Clean all residue with castile and Tween 20 wash. Rinse thoroughly with Flo and cold water and rinse again with just cold water. DISCOLOURED ORGANIC STAINS Treat the area with morpholoene for several minutes and bathe with pyridine. Repeat the process and wash with Flo rinse and castile wash. Clean with cold water rinse. LUBRICANT STAINS Ifstains remain affer using mineral o/V, pine oil, glycerin or morpholene, bathe the stamp in fresh pyridine several times until all traces of stain are dissipated. Stamps should be dried between several layers of acid free filter paper. 26 INDIA INK Prepare the softening or lubricating of the stain by treating with pine oil. Lei the oil permeate for several minutes; brush the loosened material way. Immerse in alcohol (91% has less water) and brush freely until stain id dissipated. Wash with castile and then plain cold water. If this procedure falls, soak stamp for 30 minutes in Degest. Then repeat the procedure. PRINTERS INK AND MARKING INK This is the most difficult ink stain to remove. Soffen the stain with pine oil several times. Brush away stain particles and wash repeatedly with soap wash. TYPEWRITER INK AND STAMP PAD INK To the try of castile wash, add several drops of Tween 20 and a small amount of ammonia water. Brush smoothly and thoroughly. Wash well with Flo rinse and repeat the process. Rinse finally in cold water. CARBON PAPER STAINS Swish stamp continuously in amyl acetate for several seconds, a/r dry and repeat process. Wash in castile and Tween 80 bath. Rinse well in cold water. BALL POINT PEN INK STAINS D/p stamp into toluene and them amyl acetate. Wash in Tween 20 and castile bath. Repeat process, brushing gently. Rinse in cold water. 27 INDELIBLE PENCIL STAINS Brush generous amount of warm glycerine on area. Lei glycerine stay for about 2 minutes. Wash completely with castile and Tween 20. Rinse in Flo and then in cold water BLUE BLACK WRITING INK Soften the ink with warm glycerine for several minutes. P/ace the stamp in half strength Dilute Hydrochloric Acid for only several seconds. Rinse repeatedly and wash with Castile soap bath. RED AND GREEN INK STAINS Lubricate and sotten the ink stain with warm glycerine for several minutes. Wash rapidly with castile bath followed by Tween 20 rinse with castile. Rinse with cold water. LACQUER STAINS P/ace the tamp in tray and carefully lest the ink for resistancy to acetone. This fest should be done actually, with any chemical. P/ace a few drops ofthe acetone on the filier paper and touch lightly on the face of the stamp. If no colour was transferred then the colour will remain fast. Brush the acetone across the stain carefully for several seconds. Lei the stamp dry. Repeat the process until the stain is removed, being careful not to remove colour by mere brushing pressure. Wash only if the stamp is non fugitive in nature (castile bath). PAINT STAINS Prepare a bath of 50% alcohol (91%) and benzene. P/ace the stamp, stain side down for 10 seconds. Turn the stamp over and brush lightly until all traces of the stain have been removed. If necessary, wash in castile bath. Rinse well. 28 RUBBER CEMENTAND SCOTCH TAPE Prepare a solution of 50% toluene and 50% benzene. Follow the procedure äs before, brushing lightly so äs not to disturb and übers of the stamp. SHELLAC STAINS Immerse the stamp in a bath of ethyl alcohol, the higher the concentration, the better. Follow the brushing, drying procedure, Use a castile wash and rinse well. WATER RESISTANT GUMS Prepare a solution of 5% acetic acid in the tray and place the stamp face up mithin the solution. Sprinkle Degest liberally and stir slightly. Reaction time should be less than 40 minutes. Wash thoroughly with cold water. THE NEW SELF STICK ADHESIVES This technique is probably the longest to accomplish and requires soaking in benzene which has been warned. CAUTION: this is a flammable liquid and some stamps will lose all their colour. After the stamp has soaked forseveral hours, completely wash the stamp in castile bath to which several drops of Flo and Tween 20 have been added. Rinse well in cold water. Older types will require the use of mythly-ethyl-ketone. SILVER NITRATE INK STAINS Paint the area with mild iodine solution: follow this with a 5% sodium thiosulfate solution. Wash with castile bath and rinse with cold water for several minutes. 29 IRON STAINS Immerse the stamp in 10% citric acid solution in the tray. Leave for approximately 90 seconds and then wash with castile bath. If the stain is still present, dip the stamp in concentrated sodium Chloride solution and then immerse in the 10% citric acid, If the stain is still resistant to this treatment, dip it in a 5% oxalic acid solution and repeat the entire process being careful to wash thoroughly. Repeated stroking with the säble brush is necessary. An alternative procedure is to first treat the stamp with a 0.3% solution ofammonium solfate to be followed bya wash in a 4% solution of oxalic acid. Wash with castile bath and rinse thoroughly. THE BLEACHING OF STAINS It should be noted that bleaching may not only remove the unwanted stain, but in many cases it may well remove constituents ofthe in k with which the tamp was printed. It is the most drastic procedure and should be used only when all eise falls. There is no way to correct overbleaching and the timing must be watched carefully, for once the Vignette has faded, there is no recourse. Many bleaches can leave a stamp's paper in pieces. STAMP 0X1DATION The following does not refer to the "oxidation" usually referred to, which is sulphidization or sulphurization, äs it is sometimes called. This is due to the fat that certain metallic pigments which are basically oxides will absorb sulphur dioxide or hydrogen sulphide, offen present in the a/r in minute quantities. As nearly all metallic sulphides are black (there are only three or four exceptions to this rule) this absorption of sulphur compounds blackens the stamp affected. The sulphur compound formed may be re-ixidized, äs most collectors know, by using H202 or peroxide of hydrogen, which gives up its extra atom of oxygen and displaces the sulphur. The "oxidation" is called 30 "foxing" äs a rule. This foxing is the reddish or brownish spotting we find in old books, some of which have a very decided odour äs a result of it. Foxing is caused by plant growths related to bacteria, fungi and moulds. It attacks stamps in all humid climates, The worst case we have ever seen was on a set or /arge bicolor "Omaha" die proofs, which were completed obliterated by it, both stamps and margins. These were restored by cautious application of a b/eaching solution Chloramine T. So-called "rust" in stamps is referred to äs a "brown mould", "oxidation", "foxing" etc. Actually it is fungoid or bacterial in nature. First of all it would be well to deal with the manufacture of paper, which is the root cause of the infection. Fibres of various kinds, all of vegetable origin are digested into pulp with the aid ofsodium oxide, sodium sulphite and sulphurous acid. The resulting mass in its crude state is called "cellulose". Bleaching is effected by various mixtures such äs calcium Chloride and calcium hypochlorite; these produce chlorine which, in turn, releases oxygen. Acidity is neutralized by adding sulphite or hyposulphite soda. The cellulose is loaded with china clay, and at this stage colouring matter is added if desired. The fluid mass is passed under pressure through a strainer to remove such solids äs exist, and then on to a mould that allows the liquid to drain off. After drying, the paper is absorbent, ie "blotting paper". This is then sized by treating the surface with a composition of gelatine and/or resin in solution. It is subjected to further drying and pressure, and is then ready. The gumming of stamps is done by applying dextrine, ie a dilute composition of starch and nitric acid, with or without hydrochloric acid or oxalic acid. Now these raw materials, vegetable fibres, wood pulp and clay, all contain abundant bacteria, and the manner in which we keep our collection is liable to provide suitable conditions for their growth. 31 The most important consideration about papers which are to be kept for any lengthy period under humid conditions (such äs prevail in South Africa) is that of the "furnish" or surface sizing. Mechanical wood pulp by reason of the unsaturated character of the product and high quantity of lignone, is liable to autoxidation and should be avoided. The most suitable type of paper is one made from chemical wood pulp alone, preferably a bleached chemical pulp, the paper finished off very slightly on the acid side with a/um. All these remarks on paper refer to that used in the manufacture of stamps, album leaves, hinges and even the covers ofalbums. It is this vegetable composition of paper which, in conditions of moisture and lack of light, permits bacterial growth. The growth is not at first visible to the naked eye but usua/ly appears äs brown specks on the teeth of the perforations, gradually spreading until it covers the whole unprinted portion of the stamp, but very seldom attacking the printed portion. It has been said that it appears more on the gummed side of the tamp (in the case of mint stamps) but äs the growth takes place in the centre of the paper- that is under the surface it is a matter of visibility. Under a strong microscope the infection loses its colour, and the paper has a raised appearance. From observations made, it is possible to lay down some rules for the safe housing of collections, the first of which should be the careful selection of albums and album sheets. Owing to the additional chemical treatment of "black" sheets these being the most resistant are the most desirable, but care should be taken that they are of good qua/ity, and of chemical wood pulp äs referred to before. Then the selection of the Container for the stamps and albums is important, äs the wood should be of a dry variety, so assisting in absorbing the moisture. Experiments in this direction have been carried out, sandalwood and camphorwood chests being used. It all depends on the amount of moisture which is al/owed to percolate in to the Container, äs when this is eliminated we remove the most important factor of bacterial growth. An example of how moisture can be carried in minute particles of dust can be here given. It was noticed that paper and paper manufacturers which 32 were kept under cover in a receptacle in a direct line of draught gradually received a fine coating of dust which, on being removed, disclosed the "brown mould" under each deposit. There are numerous methods ofcombating the presence of moisture in ordinary receptacles, such äs cupboards, wardrobes etc. The cheapest, ad one which will not to härm by contact, is a piece of old soap, which has become very hard and shrunken. This will absorb all moisture present. Contact of the tamps and leaves with the hands and arms should be avoided at all costs, äs it is those parts touched which very soon show signs of infection, especially if the stamps are put away, and not aired from time to time. There is a method of protecting paper and stamps against the "brown mould" infection, for those ready to undertake the task, and Thymol is the remedy. For the treatment of album leaves, melt thymol crystals into sheets of clean white blotting paper, by using a hot iron. This impregnated blotting paper should then be interleaved between the album leaves and the book kept under a weight for a few days. This will sterilize the book and there is no risk of damage to the stamps. We can now deal with the most effective remedy for removing "brown mould" from stamps - that is, from stamps, äs the remedy, when coming into contact with the gum of mint stamps, dissolves the gum (although taking out the "mould" or discolouration). The remedy Chloramine T, is very cheap and a mixture of 2 grammes with 100 cc distilled water is ofample strength to clear the infection. In the case of a very badly discloured stamps, two or more applications are necessary. The stamps can either be immersed in the solution, or a small water colour paint brush may be used. A warning should be given äs to chalk surfaced stamps, äs owing to the bleaching qualities of Chloraminen T, the surface will be adversely affected. As it known, tamps printed on chalky paper are specially prepared to prevent the eradication of cancellation marks, and, aside from contact with liquids, the surface can be removed by friction 33 It has been established that stamps treated with the solution do not show a recurrence of the infection, and tests made prove its efficiency over a period of some years, even with stamps kept in dose proximity with others containing the mould. There are many grades of quality in papers used for postage stamps, and among those used for Union of South African stamps the most receptive to mould are the four Airmail stamps issued during 1925. These are invariably found damaged among collections in the tropical areas. The issues from the Georg/ans to the London-printed pictorials are very prone to infection also, but the later issues seem to be more resistant. There is no doubt that the paper used for the Victorians was of far better quality than that used for the post-Victorian issues, and the modern process of paper-making is no doubt responsible for this. Unfortunately we cannot treat damaged mint stamps with Chloramine T solution without damaging them in another direction. Until a suitable remedy is found the only alternative is to remove the gum and treat the affected parts with the solution. SULPHURATION, MILDEW, FOXING, IRON RUST STAINS Prepare fresh hydrogen peroxide by filtering it through a pledged of cotton which has been inserted into the neck of a glass funnel. The resulting filtered liquid is then placed in the tray and a small plastic screen is laid across the top. Place the tamp face down on the screen, having cut an area wide enough so that most of the Vignette is exposed to the vapors. Place a glass slide over the entire tray, thus containing the vapors within. An alternative device would be to saturate the cellulose filier within the Stamp lift and place the stamp face down. Close the lift and rotate the stamp periodically until the original colour returns. When bleaching, always consider the conditions of the stamp. Many inks and papers can withstand very little bleaching. Wash the stamp well after any bleaching process, to avoid any alter bleaching. This procedure is also effective on stains where all other procedures have failed, or where the residue from other procedures are left. An example of this would b eater stains, and after cleaning spots. The bleaching treatment will tend to eliminate bacterial and fungous stains. 34 When you have mastered the bleaching technique, you may wish to place the stamp directly into the peroxide. You must watch the face of the stamp constantly following this procedure; A mixture ofone desert spoon of peroxide of hydrogen to half a pint of water (a stronger mixture will visibly bleach many colours and paper and in any case one should watch the patient and remove it immediately before the slightest unnatural appearance takes place). This process will offen restore the original colour of stamps printed by recess method, where the colour has been climatically affected (the socalled but ill named "oxidized" discolouration can be removed) An alternative bleaching method is the use of Chloramine T. Prepare a fresh solution of 3% Chloramine Tand immerse the stamp until the desired bleaching has taken place. Whilst this is äs effective äs peroxide, it is a much s/o wer process but requires less rinsing. The fastest bleaching method consists of immersing the tamp in 0.5% potassium permanganate solution for no more than a minute or two. It must then be quickly removed and dipped into a 2% sodium thiosulfate solution which contains several drops of dilute hydrochloric acid. One of the problems with bleaching is the after effect on the paper of the stamp. The paper will become lifeless and drab. To correct this, one has merely to paint the stamp with very dilute gelatin solution and retone the face with coffee or tea. STERILIZA TION OF BACTERIA Damaging bacteria can be controlled by vaporizing a thymol crystal under the heat of a bulb. The resulting aromatic vapor will sterilize the stamp when held within the path of the heated crystal. 35 HUMIDITY Damp affects the colour of many stamps and makes many unused stamps stick to each other or to the album page or to something eise. Almost equally it affects the used stamp which if on a letter will become detached, if on an album page cause foxing in a greater or lesser degree, fostering minute fungoid growths which stain both stamps and album page with little brown spots. The use of silica gel will eliminate the humidity thus preventing rust (foxing). Having taken all reasonable precaution to avoid damp, ifyour collection is affected by this menace there are several treatments that can be effective if the moisture has only been present for a short period. Basically there are two processes, dry and wet. A fan driver warm-air heater directed onto the open bound album or individual pages removed from a loose leaf album will soon make album pages crisp. If the stamps are stuck to the album page, then having warmed the back of the page, take the top of the page in the right hand, hold the bottom of the page in the left hand, and pass the page over the sharp edge of desk or fable. As the paper passes over the edge, the right hand should draw the page downwards. If you are in luck the stamps will spring off the page with no damage or less other than the album page. If stamps are stuck down tightly on an album page, do not try and save the page. The stamps may be removed from the album page by several methods and one must really know something about the method ofprinting and the degree of colour fastness of the stamps before choosing one method in preference to others. The wet methods are: 1. 2. 3. steam on the back of the album page till by experimentation the stamps are loosened, removed and dried moisture at the back of the page (sometimes in the sweat box) Benzene on the stamps 36 The wet process can easily affect fugitive colours and ruin gum, but it is speedily effective and generally satisfactory if one takes the troub/e to watch the patients all the time. HEAT Heat can be even more destructive than humidity. Quite apart from fire which totally destroys, a hol climate sooner or later will always affect stamps mounted in a collection unless great precautions are taken. For this reason, stamps from collections formed in places like the Islands in the West Indies and Malaysia are invariably "browned" or "tropicalised" and there is little one can do other than wash the stamps. Stamps which have been kept in countries where the climate is hot and dry are less likely to suffer except that the natural moisture in the paper of the stamps tends to dry out and the paper become brittle; if the stamp is unused then the loss of moisture causes the paper shrinkage to crack the gum and creases appear on the surface of the stamp. If such stamps are to be preserved from disintegration then there are only two actions that will halt the process. The stamps must either have the gum removed, an action which is anathema to the real Philatelist or they must be placed in the humidor or sweat box for an hour or more so that the paper may absorb the moisture it has lot and then slowly expand; meanwhile the gum softens and when the appearance is normal the stamp should be allowed to dry and then be placed in a press under medium pressure for an hour or so. This treatment takes patience, but over a period varying from an hour to several days, according to the degree of dehydration of the patient, an enormous improvement will be noted and, in some cases, complete rehabilitation achieved, although it may be necessary to repeat the treatment more than once. DEACIDIFICATION Once it has been determined that deterioriation of paper fibers could be attributed largely to acidity within the fibers or to acidic atmospheric conditions which produced correlative acidification 37 within the fibers, it was then necessary to find those means of arresting the acidity and, if possible, of reversing the acidification process, ie of deacidifying the fibers. Innumerable tests resulted in the use of calcium compounds äs the deacidification agents. The reason for selecting these calcium compounds was that previous tests of old papers, still strong after several centuries of natural aging and with a pH 7.0- 8.0, indicates that it was calcium carbonate probably resulting from early bleaching methods or washing the rags in hard water that gave them their mildly alkaline or near neutral condition. These calcium compounds were Solutions of calcium hydroxide and calcium bicarbonate. The first solution was intended to neutralize the acidity of the fibers and the second to remove the residual hydroxide of the first solution. The answer came with the discovery ofthe use of magnesium bicarbonate äs a deacidification agent; the answer to the second came with the discovery that "spraying with the magnesium bicarbonate solution effectively neutralizes acid paper increases their flexibility that papers so deacidified show good stability after heat aging that the neutralizing effect ofthe spray extends throughout the thickness of the paper. The beginning of the deacidifcation process is actually part of the cleaning routine äs it involved the testing of inks. The testing of inks is one of the simplest procedures to be encountered in the total restoration ofthe stamps and, at the same time, one ofthe most vital. The materials involved are of the greatest simplicity also, they are two: a small cotton swab and some water. The saturated cotton is briefly touched to the stamp. See if any of the ink has been absorbed by the cotton, for should there be colouring on the swab, this fact would indicate that the ink would fade and must, therefore, not b subjected to the usual methods of deacidifying. 38 Once the ink is determined to be safe or stable the stamp is immersed in a solution of magnesium bicarbonate for a period of some twenty minutes. Dry well between blotters. 39