"Partial Monochromacy" does not exist

[TheGreenSquare]

This video from Chromaphobe goes into much more detail than I ever could, but in short:

• "Partial Monochromacy" does not exist, but could be better represented as "Mixed Anomalous Trichromacy" (which could theoretically exist, it just hasn't been spotted in the wild iirc (1 in 1,500,000, anyone?))
• The existing "Monochromacy" filter is for Blue-Cone Monochromacy and should be specifically specified as such
• There is no setting for Achromatopsia (or Rod Monochromacy, where you only have rods (i.e. your eyes' backlights))

[michelf]

That's a good video. I've been aware of this issue for a little while now, so I'll need no convincing. 😎

I'm actually already working on new filters for Achromatopsia and Blue-Cone Monochromacy to replace Monochromacy and Partial Monochromacy. Initially for Sim Daltonism I simply used the HCIRN algorithm and did not dare change how it works. But now I know better and clearly it's not perfect, not to say flat out wrong when it comes to Monchromacy. So I rewrote these two filters from scratch and will make a beta soon to gather some feedback.

I discovered the Monochromacy filter is actually using the NTSC luma coefficients which are just an approximation of how the normal eye perceives brightness. NTSC luma coefficients are definitely not meant to be a representation of neither Blue-Cone Monochromacy or Achromatopsia. In particular, BCM allows distinguishing colors on the yellow-blue axis, but brightness levels are closer to Achromatopsia.

I'm planning to keep the old Monochromacy filter, renamed to "Analog Monochrome TV" to show the difference between normal "black and white" people are used to and Achromatopsia. Otherwise some people may not notice there's a difference between Achromatopsia and "black and white" and think the two mean the same thing… especially given older versions of Sim Daltonism and other tools might tell them so. So the filter stays, but will be correctly labeled.

Anyway that's the plan. Feel free to add more info more if you like.

[TheGreenSquare]

Fired a pull request up for MAT, it's #29.

So I guess the plan is:

Main

0. Trichromacy (Normal Colour Vision)
1. Protanopia
2. Protanomaly
3. Deuteranopia
4. Deuteranomaly
5. Tritanopia
6. Tritanomaly
7. Blue-Cone Monochromacy
8. Achromatopsia (Rod Monochromacy)

Bonus

9. Mixed Anomalous Trichromacy ("Partial Monochromacy"/"Achromatomaly")
10. Analog Monochrome TV (Traditional Monochromacy)

Notes

• I was thinking of using Ctrl+0 for AMTV instead of NCV (and having NCV use backspace instead)

[michelf]

Sorry, but I'll have to decline this pull request #29, not because it's wrong but because I have a ton of changes (including the new filters) I'm about to push from a local working branch and it will fail to merge… especially since I already revised the list to match the new filters on that branch.

I'll post a comment here when I push the branch.

[TheGreenSquare]

Got it.

[michelf]

Code for 3.0 has landed in master, with the new filters and the new names. (Consider it a beta at this point.)
There's also a pre-build binary here: https://littoral.michelf.ca/apps/sim-daltonism/sim-daltonism-3.0-beta.zip

[TheGreenSquare]

Checked the latest commit, still says Partial Monochromacy in some places.

(also, functioning in some places is spelt as "functionning")

[michelf]

Corrected both, thank you.