Backlighting panels

Hi guys!

I've been trying to build panels with backlighting like this one:

http://kazey.flitepal.com/cockpit_build/backlit_panels/20170524_222631mod.jpg

While researching, I came across videos and some topics:

https://aviation.stackexchange.com/questions/2608/how-are-backlit-aircraft-panels-for-simulators-made

https://www.youtube.com/watch?v=J5efmnMKkMs

https://www.youtube.com/watch?v=UIGPb0ko0qE

https://www.youtube.com/watch?v=9g2ipxu-VgM

https://www.youtube.com/watch?v=vf7tQNYqliw

Those topics and videos refer to some sort of "laser color", "opaque special white laser color" etc., which is something I cannot understand very well. It sounds to me that they are using a special paint that laser doesn't burn.

What I got from the building process, is that it starts with clear acrylic, then this special white is applied, then black layer to stop backlighting, and then the final color. At the end they treat it with the laser to achieve high-contrast lettering.

What I've tried so far, is getting opal white acrylic, figuring that when I paint it, and then remove the paint, I would get high contrast white. Yes, but no. This is my try:

http://kazey.flitepal.com/cockpit_build/backlit_panels/wiper_2.jpg

This has been painted black, and then with gray-blueish color, then laser engraved. The laser seems to burn the paint and leaves the acrylic with with some grayish shadowy color. Not what I desire to achieve. I did not apply white, because a) I am using opal acrylic and b) I am afraid the result will be the same.

However, once backlit, it looks okay:

http://kazey.flitepal.com/cockpit_build/backlit_panels/22641966_10214242823895493_1532820798_o.jpg

But I want high contrast white when not backlit.

Does anyone have the secret?

Regards,
 Ivan