I an avid Lego collector since childhood but I suffer from color blindness.
My beautiful wife usually helped me determine certain Lego colors when separating (i.e. brown and reddish brown or light gray and light bluish gray and many transparent color variations.
However, I recently had a breakthrough that now helps me TREMENDOUSLY and I feel it needs to be more wide-known.
(Reason I posted under suggestions, perhaps you could spread the word)
When looking at neon transparent Lego pieces under a black light, I noticed that even solid colored Lego bricks could be seen differently under it!!!
Light gray blocks remain the same while light bluish gray blocks glow under the light!
This also works with all other Lego colors, especially the transparent vs. neon transparent!
I find this helps the absolute most when dealing with a mixture of older and newer Lego. The colors and clarity are sometimes very hard to determine.
The black light fixes this issue!!!
Hope this helps many more, colorblind and non colorblind people alike!