Hi Andrew,

  I think the difference in brightness of the colors shown in ChimeraX compared to the RGB hex code you are using is because of lighting, not colorspace.  Even in flat lighting there is an "ambient intensity" lighting setting which is set to 1.4.  You can see the lighting settings with the ChimeraX lighting command

> lighting
Intensity: 0
Direction: 0.577,-0.577,-0.577
Color: 100,100,100
Fill intensity: 0
Fill direction: -0.2,-0.2,-0.959
Fill color: 100,100,100
Ambient intensity: 1.45
Ambient color: 100,100,100
Depth cue: 1, start 0.5, end 1, color 0,0,0
Shadow: False (depth map size 2048, depth bias 0.005)
Multishadows: 0 (max 1024, depth map size 1024, depth bias 0.01)

When I change the ambient intensity to 1.25 after setting flat lighting

> light flat
> light ambientintensity 1.25

I get exactly the same hex code color in ChimeraX as I used in my color command as reported on a Mac using /Applications/Utilities/Digital Color Meter.  I expected the matching ambient intensity value to be 1.0, but for some reason it is 1.25.

  I'm not sure why you need this.  ChimeraX is for 3D rendering and lighting is critical to getting a good 3D appearance, so the intensity of colors varies based on the angle of surfaces to the view direction, specular highlights, shadows, ....  It is a rare case where you want to use flat lighting.

        Tom


> On Mar 5, 2026, at 11:10 AM, Andrew Kennard via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
>
> When I color models using hex codes of colors I would like, they are noticeably brighter than the colors I am trying to specify with RGB hex codes. I am selecting colors based on the rest of my figure (which is being built in the sRGB colorspace/color gamut in Adobe Illustrator). I realize that the lighting settings in ChimeraX can change apparent colors, so I am using the "Flat" rendering mode to hopefully minimize that effect.
>
> But when I take a hex code I have selected in Illustrator and try to color the model with that hex code, the result is generally brighter than the color I specified.
>
> I suspect this is a mismatch in color gamut, but maybe it is still due to lighting? Is there a way to modulate the lighting in such a way that I can try to recover the colors I intend?
>
> Thanks!
>
> Andrew
> _______________________________________________
> ChimeraX-users mailing list -- chimerax-users@cgl.ucsf.edu
> To unsubscribe send an email to chimerax-users-leave@cgl.ucsf.edu
> Archives: https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.cgl.ucsf.edu%2Fmailman%2Farchives%2Flist%2Fchimerax-users%40cgl.ucsf.edu%2F&data=05%7C02%7Cakennard%40umass.edu%7C489927df19964dd9b04a08de7b2ae2a2%7C7bd08b0b33954dc194bbd0b2e56a497f%7C0%7C0%7C639083621288350508%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=BqXBmd6HdNXPORnNiZlxgJG%2F7m5bfPcvyTSoLzCxrAw%3D&reserved=0