Thanks for the recommendation. I tried it out as a colorblind person. I'm always looking for one of two things -- tools that will help me differentiate stuff I see on graphs and charts (endlessly frustrating) and tools that will let me show other people how I see.

My problem is that I've never found a colorblind emulator that matches my colorblindness. I'm just red-green deficient, so nothing exotic.

My test for these emulators is whether I see a difference between the original unmodified image and the emulated colorblind image, and I always do. Even with this one. So that tells me that the emulation doesn't really match what I personally see or I wouldn't be able to tell the difference.

I haven't used sim daltonism, but most of these simulators assume your opsins are fully non-functional. You usually have multiple copies of the relevant genes and most of them need to be non-functional for complete colorblindness. Most people are only partially colorblind as a result, from what I understand.

Additionally, mutations can shift your spectral sensitivity curves away from "human normal", which further affects color perception.

The thing is though, no two people's colorblindness is exactly the same, so this is difficult to tune.