The TL: DR is that Scratch's eyes as seen in the show are the same as Dash's. But here's a wall of text and helpful visual aids to help explain.
Magenta is not red (and it's not really violet either).
For reference, this is Dash's eye pulled right from the official artwork (and ergo how I made my color guide). The eye gradients are always composed of at least two to three colors, and they all go from a darker to brighter luminance. It never goes dark-light-dark, though it can certainly change hue.
I've also included a screengrab of Dash from the show.
The flash assets used in the promo sites are the real deal from Studio B, the web people are not reinventing the wheel (and anyone who says otherwise hasn't actually dug into the flash files in the past). This has been the case since day one of the flash promo sites. But for argument's sake, I'll repost the ripped elements.
Now, to be fair, I'll grant that there may be some color management issues (given that Flash is, generally, not color managed in browsers) but it's within the ballpark for Scratch, especially that it has the proper stroke and body colors. Compare this to what I just posted for Dash, and you'll see that they're pretty much the same. These eye colors have also been used by multiple background ponies, like these ones here. If you think her fills aren't right, well, check out my guide to white ponies
. Scratch isn't white (and never was, people just nabbed her night colors).
Berry Punch also uses the same ones.
As far as the scene in the finale goes, someone (beatfox on ponychan) actually went and saved me the effort from doing color correction (as I have done in the past for Scratch
). Yes, when she lifts up her glasses she is in a tinted/bluer environment, but that's trivial to fix.
The key to color correction is to make the scenes match, and there's no automatic way to do it. You can't just click on what you may think is neutral with eyedroppers, because they may not in fact be colorimetrically neutral! The speakers, for example are all warm grays. Scratch isn't pure white either, so you can't use her coat. However, the show's usage of blacks and whites for eyes are "pures," and these are a good starting point. That won't help with midtone correction, but anyone who has had to fix gray balance issues for a press should be able to pull this back into place.
This guy actually did about what I would do in terms of corrections (compare the neutrals in the speakers, they're pretty damn close to each other, though not exact, and the ponies' actual colors are also fairly matched) and you'll see that the eye color looks pretty much like the rest of the bg ponies and Dash posted earlier.
I'm not going to go digging through every episode to find every instance, but suffice to say that given the propensity to reuse this color set (and others) for eyes very frequently. So, given the fact that they love to reuse these colors a lot (and that that the only background pony I've ever seen with blood red eyes has been Big McLargeHuge), I'd say it's fair to say that Scratch's eyes are the same as Dash's.
With all that said and done, I've updated Scratch's guide to have swatches for eyes. They're copy and pasted from Dash's guide. EDIT UPDATE:
If you don't believe me, check this. Several days after this was posted, someone asked Sabrina Alberghetti, one of the storyboard artists, and she replied that the colors are the same as Dash's. See the comment on her profile here: comments.deviantart.com/4/1453…