But it's red on green or green on red, not differentiation between the two? I have r/g color blindness, I can't see red berries against green foliage, but I can tell red from green easily.
I'll explain what the difference is here. I suggest all software developers learn to use something like http://www.vischeck.com/ on their UIs:
The colors "Green" and "Red" aren't visible at all to R/G colorblind people. There are actually two different types of cone deficiencies (for R/G colorblindness, the most common one), missing red cones, and missing green cones (Deuteranope and Protanope). Turns out, it doesn't really matter that much which one you're missing, as the world looks much the same to you: All yellow and blue. There are some differences, which do mean the specific yellows you see are different from the other type of R/G colorblind, but for software developers, both types of common colorblindness can be lumped together: Only use Yellow and Blue as indicator colors, or colors that clearly go to yellow or blue, or use secondary markers.
For severe cases, the colors you see are pretty much only yellow and blue. For less severe cases, the person actually is only missing SOME of the red or SOME of the green cones, and can tell some colors, but not very well.
There is also a Tritanope which actually has problems distinguishing blue/yellow, but they're VERY rare.
Vischeck.com (which I'm just a frequent user of) will also Daltonize images for you. What daltonization does it it takes colors in an image and moves them around in the different color spaces to make it so both normally color sighted and color deficient users can see everything.
I am not an expert, but merely a software dev who tries to do right by the color deficient, 8% of North american males.
