Luminous Contact Lenses
This is a pair of one of the first luminous contact lenses ever made. In short, luminous systems are various solutions that use some kind of filters (glasses or contact lenses) to read marked cards. Detailed explanations can be found in our chapter on marked cards, under luminous readers. As a general rule, these kind of contacts lenses are supposed to be used with any kind of Luminous inks or luminous daubs.
This is a pair of the first luminous contact lenses ever available on the market, sold by crooked gambling supply houses, such as the KC Card Co, Hunt & Co, Mason & Co... etc. These lenses are really unpractical, if not impossible, to use in an actual card game, as it should appear quite obvious that the operator is wearing contact lenses. Since they are made from hard material, they are really hard on the eyes and very difficult to use. The ink that was typically sold along with these contact lenses was emerald green.
More commonly known luminous systems use red filters that are used in conjunction with red-backed playing cards. Blue luminous systems work on a slightly different principle, than red systems. While a red-lens system works primarily on the principle of color blocking, thus canceling out the red back design of the playing cards to bring out the hidden markings, a blue luminous system is not actually designed to be used necessarily on blue-backed cards. The secret of a blue luminous system is not commonly known but it usually uses a stain that disappears from the cards after some time period. However, it is questionable how effective the early blue luminous systems used to be.
It should be noted that one of the earliest descriptions of a luminous system in print appeared in the classic book, Protection: The Sealed Book. Interestingly, the luminous system described in that book is a blue-lens system. However, the description in that book really makes me doubt that the system described therein ever even worked. I have even tested the principle of a blue-lens system as described in the book and the results were nowhere near what one would hope. Typical for failed luminous experiments, the markings have to be so strong that one no longer needs the filters to see the marks, and the other way around, if the work is light, the filters don't help either.
This is not to say that blue luminous systems do not exist. However, the one blue-lens system that I am fairly familiar with requires filters that are very different in appearance than these contacts, which leads me to believe that these contacts may have not produced the best possible results.
Below are two clippings from the 1961 KC Card Co. Blue Book, advertising their contact lenses. The contact lenses pictured above are quite possibly the same ones listed in this ad.