Years ago (about 20) after hearing about painted edges improving the sound of CD's, I theorized that to work, such a marker would need to prevent the reflection of the 790nm laser light at the edge of the CD's in my CD player, either by absorbsion or transmission at the edge of the disc. Working with markers that I could find in a local craft shop (water washable so I could change colors easily) I decided to experiment with transmission properties. The result was a definite change in the sound of the discs I applied the markers to. I concluded that purple worked best, and after comparing the various colors to a color frequency chart, I found that its wavelength was closest to being an even multiple of the laser's - which I had expected to transmit best through the edge of the disc. I later set up an experiment to test my theory and found that the purple marker did indeed have the greatest tranmistivity of all the colors I used (for absorbsion I expected that opaque green would be the best at absorbing the laser light).
When I switched to permanent markers I found that they became somewhat opaque over time - no longer the clear purple color that worked so well in the beginning. I then switched to paint markers (also from my local craft shop) and found that various colors of green also worked well (my absorbsion theory). I later tested the Stoplight pen against the green markers I was using and found that its particular green color seemed to be best overall, so consequently I chose to use it for my discs, and still use to this day.
It was all an interesting project for me which if nothing else, at least convinced me of the validity of the Stoplight pen, which I now use on all of my serious listening CD's. Too bad they will no longer be available - guess I better stock up! :o)
When I switched to permanent markers I found that they became somewhat opaque over time - no longer the clear purple color that worked so well in the beginning. I then switched to paint markers (also from my local craft shop) and found that various colors of green also worked well (my absorbsion theory). I later tested the Stoplight pen against the green markers I was using and found that its particular green color seemed to be best overall, so consequently I chose to use it for my discs, and still use to this day.
It was all an interesting project for me which if nothing else, at least convinced me of the validity of the Stoplight pen, which I now use on all of my serious listening CD's. Too bad they will no longer be available - guess I better stock up! :o)