What's the deal with coloring CD's and/or tray mechanism

kijanki
Black absorbs all wavelengths. Special infrared sinking paints, used by military, are all black matte. Cheap version, often used, is Krylon 1602. You can easily test it with infrared led (remote control etc) and cellphone (since they show infrared as visible light). Thin layer of water would be completely useless.

Actually green (turquoise) CD trays work better than black. Most stock CD trays are matte black so one can probably conclude black is not really the answer. Besides shining a red laser on the stock black tray illustrates that doesn’t absorb red very well. Probably not other colors either. That’s why complementary colors are used to absorb the various visible colors? Refer to color wheel. Furthermore, green or turquoise or cyan works better than black ink - in terms of SQ - around the outer edge of the CD so, again, one can conclude black is not the answer.

The CD laser also appears red because the primary wavelength at 760 no is just past the red into the near infrared, thus a portion of the laser beam is red. And the photodetector accepts red and near infrared light.

As for military aircraft that exhibit extremely low radar profile I’m reasonably sure you will find that the matte black is not just any old black paint but some highly specialized carbon or graphene concoction or whatever. That’s why it’s secret. We don’t want every Tom, Dick and Harry to know about it.

If I recall correctly there is a small CD company that manufacturers CD with turquoise colored labels. Which makes sense since the color of the label influences the sound, no?

in any case absorbing red light is only a small part of the solution since most of the laser spectrum is invisible, no?

ahendler
This was a big deal in the early years of CDS to try to get them to sound better. I colored the outside edge and inner edge with different colors. They actually sold audiophile coloring pens to do this at a premium cost of course. Never really heard any difference. Don’t waste your time
Alan

unfortunately only certain colors work. There was a reason they sold a lot of those expensive green pens. Maybe now that your system is better than it was 30 years ago you will hear the difference. Green on outer edge, black on inner lip. May the force be with you.

Geoffkait, pure matte black has 100% absorption of all colors. Other colors are used only to reflect only one color. Targets for infrared, for counting number of pulses in rotational speed measurements, are usually gold/matte black (including one I designed: http://himmelstein.com/images/product-datasheets/0807545dc201B8701.pdf )

As I mentioned before you can see infrared with your phone camera and test it for yourself.

kijanki
"Geoffkait, pure matte black has 100% absorption of all colors."

that cannot be true since adding gree to the CD tray improves the sound. Almost all CD trays are black or black matte. As I said you can see for yourself with a red laser poster how much is reflected off the black tray.nalso, of the black matte tray was actually 100% effective the green pen wouldn’t make any difference. Nor would painting the tray cyan. And we know that’s not true.

"Other colors are used only to reflect only one color."

I don’t think we’re on the same page. You want to absorb color not reflect it. For a given color there is a complementary absorbing color.

Furthermore, dare I even say it? Black around the outer edge of the CD actually hurts the sound. 😀

"Targets for infrared, for counting number of pulses in rotational speed measurements, are usually gold/matte black (including one I designed: http://himmelstein.com/images/product-datasheets/0807545dc201B8701.pdf )

As I mentioned before you can see infrared with your phone camera and test it for yourself."

the reason you see the infrared is because it’s near infrared next to the visible part of the spectrum thus part of the signal is in the red zone. Same for a CD laser. Hel-loo!