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Ultraviolet Light and Black Light: a beginner's guide
by David Rudd Cycleback


1) Introduction

2) What is ultraviolet light?

3) The different kinds of UV light

4) Your tool for this guide: a black light

5) Where does ultraviolet light come from? How was it discovered? Why can't we see it?

6) How are black lights made?

7) Practical and interesting uses for your black light

8) Examining art and collectibles: Introduction

9) Identifying modern fakes of antique paper memorabilia

10) Identifying counterfeit US currency

11) Identifying alterations to art, collectibles

12) Examining cloth

13) Examining art glass

14) Making glow in the dark art and crafts

15) Protecting yourself from the Sun's UV

16) UV light in science and industry

 

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Identifying modern reprints and forgeries of antique sports cards, postcards, programs, documents and other paper ephemera

A black light is effective in identifying many, though not all, modern paper stocks. This allows the collector and dealer to identify modern reprints and fakes of antique trading cards, posters, photographs, programs and other paper memorabilia. Many people buy a black light specifically for this purpose.

Starting in the late 1940s, 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. 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. If paper stock fluoresces very bright as just described, it almost certainly was made after the mid 1940s. 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 is modern.

Valuable 1880s tobacco card is shown to really be a worthless modern reprint under blacklight (right).

 

A piece of 1930s vintage paper on top of a larger piece of 1990s white paper.

 

10) Identifying counterfeit US currency

 

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