Photograph Identification Guide
by David Rudd Cycleback

Chapter 4 : LONGWAVE BLACK LIGHT: A TOOL FOR IDENTIFYING MANY REPRINTS AND FAKES

(c) cycleback 2003, 2005 all rights reserved

For collectors of Pre World War II paper material-whether it's sports photographs, theatre programs, movie posters, trading cards, scorecards or postcards- there is a sophisticated yet inexpensive and easy to use tool for quickly identifying many modern reprints and fakes. This tool is called a longwave ultraviolet light or longwave black light. While there are many uses for black light in collecting and beyond, this chapter introduces how it can be used to identify modern paper.   How Black Light Works A black light allows the collector to see things not seen under normal daylight. Ultraviolet light is outside the human's visible spectrum, meaning that it cannot be seen by human eyes. However, in a dark room different materials can fluoresce (give off light) under black light. Most of us have experienced black lights that make the whites on our shirts or shoes glow brightly. Some materials fluoresce brightly, some not at all and the rest somewhere in between. Fluorescence can differ in color. Some minerals fluoresce yellow, some red and some blue. This quality of fluorescence happens at the atomic level of the material. Identification of Modern Papers Using Black Light A black light is effective in identifying many, though not all, modern paper stocks. Starting in the late 1940s (1950s for photographic paper), manufacturers of many products began adding optical brighteners and other new chemicals to their products. Optical brighteners are invisible dyes that fluoresce brightly under ultraviolet light. They were used to make products appear brighter in normal daylight, which contains some ultraviolet light. Optical brighteners were added to laundry detergent and clothes to help drown out stains and to give the often advertised `whiter than white whites.' Optical brighteners were added to plastic toys to makes them brighter and more colorful. Today's tooth whiteners contain optical brighteners. Paper manufacturers joined the act as well, adding optical brighteners to many, though not all of their white papers stocks. A black light can identify many trading cards, posters, photos and other paper items that contain optical brighteners. In a dark room and under black light optical brighteners will usually fluoresce a very bright light blue or bright white. To find out what this looks like shine a recently made white trading card, snapshot or most types of today's printing paper under a black light. Your powder laundry detergent probably will fluoresce brightly. If paper stock fluoresces very bright as just described, it almost certainly was made after the mid 1940s and after 1950 if it's a photograph. It is important to note that not all modern papers will fluoresce this way, as optical brighteners are not added to all modern paper. For example, many modern wirephotos have no optical brighteners. This means that if a paper doesn't fluoresce brightly this does not mean it is necessarily old. However, with few exceptions, if a paper object fluoresces very brightly, it could not have been made before World War II. Using this test, the collector can weed out many modern reprints. It is important that the collector gain practical experience. This means using a black light to examine and compare the fluorescence of a variety of items. With photographs, make sure you shine the black light on all sides and edges. This is because the gelatin or other coating on the front of the paper often prevents the front from fluorescing. The collector should follow safety. If used correctly, longwave black lights are safe, and can even be used by kids. Factory boxed black lights will come with directions. Where to buy a longwave black light Black lights and ultraviolet lights are widely available and have a wide variety of uses. Geologists use them to identify rocks, collectors of glass uses them for authentication, theatres uses them to create special stage lighting. They are even used to find scorpions at night. Black lights are sold by many science, hobby or rock stores. I bought mine and tested it out at a hobby store in my home town. They can also be purchased online. I have seen hand-held models regularly offered for well under $20 each on eBay. Be sure to purchase a longwave black light as opposed to a shortwave black light. Shortwave is important in certain specialty areas, like stamps and gem identification, but longwave is the safest and all you need for photos and most paper collectables like posters and postcards. Make sure to double check, but most of the cheaper black lights offered on eBay will be the correct longwave versions. cycleback.com................photos main (c) david rudd cycleback, cyclback.com all rights reserved

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