[mpetroff]

> My initial instinct is that finding 12 colors that are visually distinguishable for all users is likely impossible.

Without going to lightness extremes, I agree that this likely isn't possible, at least when trying to accommodate all three types of dichromacy and for small color patch sizes (like those typically used for line and scatter plots). For example, you could take the 10-color accessible palette from work I've published [1] and add black and bright yellow to get twelve colors, but the lightness extremes of adding these colors would result in significantly-different visual weights. Based on a validation survey I conducted, I think even ten colors is pushing the limit of what's reasonable when lightness extremes aren't used.

> could share what colors in the 12-bit palette...are problematic

#9d5 and #4d8 is the color pair I find particularly problematic.

[1] https://arxiv.org/abs/2107.02270

[Ancapistani]

I’ve but tried to this yet, but wanted to let you know that I’m actively thinking about it and very interested.

This is far from my area of expertise, but I’ve always been interested in accessibility on the web in particular.

Thank you for responding, I’ll probably be in touch :)