Rgb
You have to understand that in electronics the three primary colors are (R)ed, (G)reen, and (B)lue hence why you see the older (but still used) "RGB" analog monitor ports on the back of your PC's.
Now, in the 500/600's the LED indicator at the top of the scanner is actually composed of the three primary colored LED sources (I am not sure if it is one tri-color LED or three separate LED's - someone, probably DonS, will fill this in for me).
So, in the software, you can alter the intensity of any of those three primary colors to get many different colors AND intensities of colors.
BUT - you have to be aware of a few things like:
1) There are normal factory variations in the LED's so the actual appearance of the light may vary from unit to unit.
2) Usage of the LED's over time will likely alter their characteristics so you may have to re-adjust in future.
3) It will probably look different outside in direct sunlight vs. inside under artificial lighting.
Also, you should know that the colors depicted in the WIN500 software (I can't speak about the PSREdit SW as I haven't tried that yet) the colored boxes depicted next to the RGB settings depict an IDEAL and do not reflect the actual color and intensity of the LED lighting you may get from your unit (though it may seem close or dead on even, at least initially).
And be aware that there is no clear LED - the "white" setting is made by combining the R, G, and B at maximum levels (FF which is HEX for 255 or the maximum setting) so you get R and G and B all set to 255 or Hex FF all combined to, ideally, appear as "clear white" light.
But there may be variations, as I said, not only due to normal factory variations but also due to aging and to the overall non-linearity of LED's.
Ideally, if all you want to do is lessen the intensity of the default colors without changing the color itself then, ideally, all you need to do is lower each of the levels by exactly the same amount. Ideally. The problem is, you may not get exactly what you intended and may have to play with the levels of each color a bit before you get the intended appearance. Hence the up/down slider controls next to each color intensity setting in WIN500. You will, likely have to "fine tune" the settings somewhat. But you can start with a 1/2 or 1/4 setting across the board and see what you get - it's at least a starting point. And remember, the colors depicted in the boxes in the software GUI are IDEAL - they may or may not match what your eye sees on your scanner.
As an example, in my case, my "white" setting at the maximum level using FF on R, G, and B actually gave me a more light blue look after some usage. So I tried reducing the Blue level but, because the mixture was somewhat non-linear, I ended up needing to play with all of the levels and came up with R at B2, G at F6, and B at 81 to get a relatively white or clear light (sorta-kinda, at any rate). This made the software's color box for that setting look like a pale avocado-like green since it probably uses an ideal linear estimation (I don't know - Don will likely correct me, but whatever it is, it is still an ideal estimation).
-Mike