Stamp Care and Preservation of Philatelic Items

(VISIBLE light and its harmful effects on your items of Philately)

Although we probably have been taught to "avoid exposure of our philatelic and stamp items to ultraviolet (UV) light," this particualr mantra is addressed on another page.

In fact, avoiding exposing our items of philately to VISIBLE light should be treated with just as much urgency!

Under normal indoor room light conditions, VISIBLE light can cause more damage than any UV light that may be present!

Increase in the survivability of paper based Philatelic, Stamp, and Art collections given their susceptibility to UV radiation and VISIBLE light Intensity
	VISIBLE light intensity
UV component in VISIBLE light	30,000 lux (average daylight)	3,000 lux (near windows, fluorescent lamps)	300 lux (Good visibility)	30 lux (minimum needed for fair visibility)
+ 750 mW/lm (daylight)	x 1	x 10	x 100	x 1000
75 mW/lm (good UV filter)	x 10 to x 30	x 100 to x 300	x 1000 to x 3000	x 10,000 to x 30,000
1-10 mW/lm (best UV filter)	x 10 to x 100	x 100 to x 1000	x 1000 to x 10,000	x 10,000 to x 100,000

Adapted from S. Michalski, Canadian Conservation Institute, Ottawa; October 1994

The blue squares above span the range of illumination that you as a philatelist, or other collector of paper based articles, should aspire to maintain when viewing and displaying your philatelic treasures. Unfortunately, the red squares represent the illumination that many of us actually prefer to use. Your failure to lower "the lights" can reduce the time before your items of philately begin to exhibit fading or damage by as much as 100 -1000 times, or even more. Stated another way, improper care can cause your stamp to be damaged in 1 year rather than in 100 years!.

Consider how it is that after 2000 years the Dead Sea Scroll to the left was found in a very readable and mostly unfaded condition. Is it because it was left in a dark cave for most of its life? The answer is in part, yes; although the fact that there was a low temperature and stable humidity environment no doubt also helped.

Now, consider a stamp born into this world in 1840; what if for the last 150 + years this item of philately was exposed to VISIBLE light, for example, as might occur at an annual exhibition of the stamp, or some other related philatelic event. Next ask the question, could exposure of this stamp have occurred near a sunlit window of an exhibition hall or museum, where despite any UV filters that might be used, the stamp was nevertheless illuminated by the VISIBLE wavelengths of the sun and/or interior lighting? Sadly enough, the answer is, yes. The literature is replete with examples of museums, dealers, auctioneers, as well as ordinary collectors that still do not understand, or choose to ignore, that ALL forms of light (not just the light known to us as UV light) will cause damage to philatelic collections. Unfortunately, because the VISIBLE wavelengths of light are those that give us the ability to view and enjoy our stamp collections, most of us are loathe to change our habits with regard to them, but change our habits is exactly what we all MUST do!

Effects of VISIBLE light on stamps (Qualitative effects using Blue Wool cards)

Our discussion begins with the "Blue Wool" cards below, which many museum curators use to estimate the effects that museum lighting has on various pigments, dyes, paints, papers, and other non lightfast materials. The Blue Wool cards comprise a set of horizontally dyed stripes. What is of particular interest is that the light fastness of the dyed stripes mimic that of many items of aesthetics, history, and value, for example, stamps and art. By exposing the stripes to light, the effects of particular amounts of light can a priori be found to be safe or damaging.

It takes about 3 times the amount of cumulative illumination to fade each stripe as the stripe that is directly above it. For example, depending on geographic location, season, humidity, the 3rd stripe from the top will begin to fade after exposure to about 3.6 Megalux hours of illumination, the 4th stripe from the top will begin to fade after exposure to about 8-10 Megalux hours, and the 5th stripe after about 30 Megalux hours.

The middle blue wool card above shows a lengthwise left section protected from all light by aluminum foil (Al), a middle section that is not protected at all, and a lengthwise right section that is protected with an ultraviolet (UV) filter. The right blue wool card shows the aluminum foil and ultra-violet (UV) filter removed after the dyed stripes on the card were exposed for 8 months to the light of a south facing Canadian window.

Comparison of the middle section of the middle and right card above against the corresponding right section illustrates that which is well known; that fading and damage can be reduced when exposure to ultraviolet UV light is minimized, for example as by a UV filter. However, perhaps the more important observation to be made is this: even when when protected by ultra-violet UV filters, the right sections of the middle and right blue wool cards above still evidenced fading. Why? ... because of something many of us fail to consider ... that UV filters DO NOT act to filter VISIBLE wavelengths of light.

Although the example above shows that filtering of ultra-violet light does indeed reduce fading and damage, it also illustrates that every time VISIBLE wavelengths of light are used to view items of philately (whether or not ultra-violet UV filters are used) some fading and/or damage will occur. In fact, each exposure to VISIBLE light will irreversibly and cumulatively add to any previous stamp fading or damage that has already occurred; the additive effects of exposures to such light is known as "reciprocity."

Effects of VISIBLE light on stamps (Quantitative effects)

VISIBLE Light Condition	Light at Surface of an Object (Approximate)
Direct Bright Sunlight	100,000 lux
Shade in Direct Bright Sunlight	10000 lux
Direct Bright Sunlight in a room	5000 lux
Halogen Lamp	700 lux
Typical Fluorescent Room/Office Lighting	300-500 lux
Typical 100 watt bulb at a distance of 3 ft	100 lux
Museum Lighting	50 lux for sensitive materials (i.e. stamps)
Wax Candle at 1 ft	10 lux
Full Moon	1 lux

The 5th stripe on the "Blue Wool" cards scale mimics the light fastness of many modern 20th century stamps. The time it takes the stripe (as well as the stamp) to begin fading can be analogized to that of filling of a "light bucket," with each exposure acting to fill the bucket with an added quantity of lux (a measure of the amount of visible light per unit area at the surface of an object - the closer a light source is to an object, the higher the lux will be). The light bucket for a modern 20th century stamp will overflow after about 32 Megalux hours (lightfastness of 5th stripe/stamp) of cumulative VISIBLE light exposure. Of course, the lower the intensity of the light, the longer it will take the bucket to be filled. Lets use exposure to different amounts of light to explain the light bucket further.

Effects of Indirect Sunlight

For example, exposure of the 5th stripe to 10,000 lux of indirect full sunlight 8 hours a day over 1 year (365 days) would cause the 32 Megalux bucket represented by this stripe to be filled with 10,000-lux x 8 x 365 of lux, or equivalently about 29 Megalux, an amount of illumination that would be just short of causing visible fading on a modern stamp.

Effects of Office or Room Light

The analogy above can be extended to understand the effects of any lighting condition. Lets consider the cumulative exposures to light that would occur in a typical room/office illuminated by bright fluorescent lamps (500 lux), in which case, with 8 hours of illumination each day for one year, a modern stamp would be exposed to (500 x 8 x 365) or 1.5 Megalux a year. At this rate, the 30 Megalux bucket of the modern stamp would begin to overflow after about 20 years of cumulative illumination (30 Megalux = 1.5 Megalux x 20 years). If 20 years seems to you to be very far in the future, consider the Declaration of Independence on the right; but for the uncomfortably low sub 50 lux of illumination used in the National Archives, the Declaration of Independence would long ago have faded from existence. It should be noted, however, that under 50 lux of illumination, even moderately lightfast materials like modern stamps (stripes 4-6) will eventually show fading after about 200 years. However, before concluding that 50 lux, 200 lux, or some other amount of VISIBLE light is an acceptable amount of illumination, lets step into the "bucket" further to see how else it can be caused to overflow.

Effects of VISIBLE Light on 19th and early 20th century stamps

The appearance of the stamp below seems to indicate that it was exposed to light for an extended period of time. How much time? Consider if instead of 32 Megalux of illumination, our bucket was able to hold only 3.6 Megalux. 3.6 Megalux is the threshold at which the 3rd stripe from the top on the "Blue Wool" scale begins to fade. In fact, the 3rd stripe mimics the lightfastness of the stamp to the right as well as most 19th and many early 20th century stamps and philatelic items, which because of the fugitive inks (reds, oranges, carmine, etc.) and type of paper used in their manufacture are much more susceptible to light induced fading and damage (i.e. a 3.6 Megalux bucket will overflow about 7-8 times more quickly than the 32 Megalux bucket of a modern stamp). Stated another way, even if a 19th or early 20th century philatelic item had been stored along side the Dead Sea Scrolls in a darkened cave for 2000 years, once it was removed and illuminated under room light conditions (300-500 lux), it could begin to show signs of fading in as short a period of time as 2 or 3 years (vs. 20 years for a modern stamp). That said, even 2 or 3 years may be an overly generous allotment of time, as we must also keep in mind that the "light buckets" of most stamps have already been filled to some extent from a multitude of past VISIBLE light exposures.

Very real world past exposures to VISIBLE light that may have already occurred to cause the "light-bucket" of your stamp or other philatelic item to overflow:

• the exposures to VISIBLE light that could occur at annual philatelic stamp exhibitions under normal room light (500 lux), for example, for one week (7 days) for 8 hours a days over each of the last 100 years, or equivalently (500 x 7 x 8 x 100) = 2.8 Megalux of cumulative exposure;
• the exposures to VISIBLE light that could occur during periods of personal viewing your stamp collection under normal home/office room light (500 lux) for 30 minutes a month (6 hours a year) each of the last 100 years, or equivalently to (500 x 6 x 100) = 300,000 lux of cumulative exposure;
• the exposures to VISIBLE light by stamp dealers and stamp auction firms that could occur during periods of showing in display cases under normal office light (500 lux) for 8 hours a day for 30 days once every 20 years (offered for sale 5 times in 100 years), or equivalently (500 x 8 x 30 x 5) = 600,000 lux of cumulative exposure;
• the actual exposure to the light that occurred at an International Exhibition Hall used by Federation Internationale de Philatelic (FIP) where some philatelic items were exposed to over 3000 lux for 8 hours a day over a 7 day period, or equivalently (3000 x 8 x 7) = 168,000 lux of cumulative exposure.

The preceding examples of possible previous exposures to VISIBLE light cumulatively add up to more than 3.6 Megalux, which in the case of the 3rd stripe of the Blue Wool scale (or equivalently a 19th or 20th century stamp) would already have caused its "bucket" to overflow; any other exposure to VISIBLE light would only cause further fading and damage.

And don't forget there are other exposures to VISIBLE light that may have already also occurred and already caused damage to your stamps:

• the cumulative exposures of stamps to VISIBLE light from flash photography;
• the cumulative exposures of stamps to VISIBLE light from photocopy processes;
• the cumulative exposures of stamps to VISIBLE light (direct sunlight?) during transit in the mails or before the availability and use of indoor illumination to view stamps;
• the cumulative exposures of stamps to acidic paper stamp album pages, storage containers, or albums;
• the cumulative exposures of stamps to improper conditions of temperature and relative humidity;
• the cumulative exposures of stamps to harmful plastics;
• the cumulative exposures of stamps to micro-climates;
• the cumulative exposures of stamps to water mark fluids, peroxide, tap water, and other chemistry experiments;
• and of course, the cumulative exposures to UV light.

How many of the exposures presented above have already occurred during your collections' lifetime? Are you now willing to take on the challenge of preventing these exposures from occurring in the future? Although it is true that enjoyment of your items of philately requires "some" exposure to VISIBLE light, you should easily be able to reduce the amount of this exposure after you consider the implications of the examples given above - can't you?

This page concludes with an image of what is presently one of, if not, the most well known U.S. philatelic treasures. As held in the hands of the proud owner, this philatelic item has been secured between two thick clear plastic (or possibly glass) blocks. If you have viewed the other pages of this web site, your first thought may lead to the conclusion that the owner's method of display can be used to eliminate the harmful effects of paper products (other than the paper of the stamp itself). Or the conclusion may be that encasement or encapsulation of the stamp in the manner shown suits itself well to items of particular aesthetics, history, and value because they can now be viewed, displayed, and stored without worry as to their damage from physical handling or display. You may, however, wish to reconsider your conclusion(s). Putting aside any considerations that a harmful micro-climate may be formed within the semi/sealed space between the clear plastic blocks, or that harmful plastic may be being used, it appears that the physical encasement of the stamp may have given the new owner a false sense of security, for in fact, this philatelic treasure has been openly exposed at more than one stamp exhibition/show, to not only to the bright VISIBLE light of the particular venue, but also the bright illumination of additional display cases that were used to keep the stamp protected from theft. On their own, perhaps these exposures to VISIBLE light may still have a ways to go before filling the 3.6 Megalux bucket of this stamp occurs, but can there be any doubt that previous owners of this philatelic item have in their own manner (perhaps the ones given above) also exposed this treasure to VISIBLE light, in which case, how much longer before this treasure (or similar treasures in your collection) will become irreversibly damaged.

 

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