Using the Mane Six coats as a match to an earlier scene in the film, I began adjusting various color and shading, etc., settings, to get an approximation of what Sunset would look like in the light. This result is not perfect, but is very close; you can directly compare the colors of the Mane Six between the two images yourself, or of course do a better job than me. While not exact, it’s good enough to get a fair idea of what Sunset’s colors as a pony would look like.
Of course, this will become irrelevant for Sunset as soon as Mirror Magic is out in HD
The process I used assumes the filter uses the multiply blending mode (this particular scene does!) Then I took pairs of colours between the filter and base image and calculated the filter opacity value that matches as best as possible for them. The more input pairs, the more accurate the result. Finally, I used the calculated filter colour and opacity to reverse the filter. Ultimately the code I wrote was really janky and there’s probably a better way to approximate the opacity of the filter so I’d like to go back and try it sometime.
Except that’s the point, her colors were brighter and it worked.
Compared to their human counterparts, the ponies have the same hair colors but more vibrant body colors. With the old colors, Sunset followed that. Then they muted her hair colors and still looked comparatively fine as a human. But then she goes back to Equestria and her coat goes back to a more vibrant color while her mane is the same. The result is that her coat is brightly colored and her mane is a more dull color.
The problem is that this is an inversion on the color schemes of most ponies, which use a muted color for the body and a brighter color for the mane. We see this in most every pony character, the mane is brighter than the coat. So now Sunset’s color scheme as a pony is at odds with the general aesthetics of other ponies, and it’s why she looks so weird to a lot of people.
Edited
Honestly I think it looks better. Her colors were borderline clashing in the super bright ones.
I’m aware. And it looks terrible.