 BetterPhoto Member |
Photo paper turning blue I'm using Kodak RC Paper, and I was messing around one day and exposed a strip of paper with a pen light. I noticed a few minutes later, the paper was developing (but I didn't put it in ANY chemicals). Upon outside examination and further testing, my photo paper is turning a blue/purple color when exposed to light (sunlight, white light, anything, although it didn't do this when I was making prints). Does anyone have A CLUE as to what's going on here?
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Christopher A. Vedros |
Photo paper will turn bluish purple or brown when exposed to light and not developed. This is normal. (of course, it's not really normal - you're supposed to develop it.) I remember learning about a process back in one of my photo classes, where you would expose a print, develop it partially, then bring it out of the darkroom to expose it to white light, then go back and finish the developing. You would get a variety of brownish purplish patterns on your print. I think this was called bromide staining, but that was a really long time ago. Chris
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BetterPhoto Member |
Good memory. Chris. I forgot all about that.
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Alan N. Marcus |
The light sensitive substance coated on photo paper is silver combined with either bromine – chlorine – iodine. These compounds resemble table salt in color and shape but the crystals are much smaller. When exposed to lots of light, the compound reduce, silver is liberated. Once liberated, the silver appears as a black dot. Next to is bromide which is brown-orange. Together they look burgundy. Silver compounds are naturally only sensitive to blue light. To extend their sensitivity into the red or green, dyes are added. Often the dye is blue-green .These dyes are water soluble and wash out during developing. In the beginning years, prints were made by placing the negatives in contact with the paper, in glass frames. Thus the phrase “contact print”. The frames were taken into the sunlight for exposure. A maroon colored print appeared in just a few minutes. Most often the print was not fixed and thus continued to darken and fade. These were proofs. Alan Marcus
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