Re: How does sunlight affect color?

Hi Laura - What I think you're asking is "how light affects the persistence of pigments?" Feel free to resubmit your question, though, if I'm missing the point. A search for colors fade on our search engine should locate some files with relevant background information in our archives.

Otherwise, you might consider the following:

Purchase some inks/pigments from an art supply store. Natural pigments may give better results than wholly synthetic ones which are likely to be more fade resistant. Apply even amounts (say a drop from an eyedropper) to identical pieces of paper or fabric. Let the ink dry. Create 6 identical drops for each color - two will serve as your "controls" - store these in the dark where they are not exposed to light. The remining 4 you'll expose to sunlight. At this point, you might want to photograph or scan your starting drops.

If you can locate a photometer for a camera, it would be good to "record" the light level on the day you choose to expose the drop to sunlight. You could also consider placing them under a lamp which might provide more constant exposure conditions. Make certain all the drops are exposed for the same amount of time to the same intensity of light. After the exposure, compare them with your control drops - do you see a difference? Another photograph or scan might be in order to record your experimental results.

Once you get your baseline results you can begin to play with the system. For instance, does the exposure time affect which pigments will fade? Which ones fade first, which ones are more resistant to fading? How does the wavelength of light affect the fading process? - you might try exposing drops to UV light alone, or to red or green light, for instance.

Hope this helps..

Lynn Bry, Admin MadSci Network