*Lots of reading ahead*
Summary @ bottom

Noticed that multi-color eyes & multi colored eyes was aliased to heterochromia by kitsu~ a while back, presumably because they feature characters with multi-colored eyes.

What if someone wanted to search for characters with colorful eyes,but not with heterochromia?(though technically they both fall under the same term, just different cases ) Such as

post #38555
post #166677
post #204441 etc.

There's also rainbow eyes and multicolored eyes/multi-colored eyes which some of these fall under, but are not necessarily heterochromia
Rainbow hair implicates multi-colored hair, so why not the eye tags as well?

Suggestions- If that makes sense after reading through, the following could possibly be implemented (it's a bit long):

Not 100% certain about the ones with an asterisk (*) next to them

Reason: To preserve the 'multi-colored_*' format

N.B. With the exception of the eye tags,most of these are relatively unused. You can find the list of what I searched for here

There's also the case of the multi-colored tag in comparison with the colorful tag.
Should multi-colored be aliased to colorful?

alias multi-colored -> colorful

Or should they remain distinct, and become an implication instead?

implication multi-colored -> colorful
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Short Version

• Was the alias of multi-colored_eyes & its variants to heterochromia justified?
• Should rainbow eyes be implicated to multi-colored eyes like rainbow hair -> multi-colored hair was?
• Lots of other colour-related aliases to preserve the format of 'multi-colored_*'
• Various implications to multi-colored
• Discussion about the multi-colored tag; should it be aliased, implicated, or something else?

Hmm, this one is a bit tricky.

I think the multicolored eyes> heterochromia implication should stay as it is quite literally discoloration of the eyes as you said.

Colorful eyes aren't always an example of heterochromia, especially seeing as it's very common among anthro characters to have vivid or strange colored eyes. I suggest it remains distinct from an alias

Rainbow eyes to multicolored eyes isn't the same as rainbow hair to multicolored hair as multicolored eyes usually (but not always) refers to one eye being different from the other. I suggest it stays unaliased from multicolored eyes but aliased to something similar like colorful eyes that still allows for a search without heterochromia.
This is the most simple solution but not entirely accurate

OR...

We alias rainbow eyes to multicolored eyes, de-alias multicolor eyes from heterochromia and alias something like off_color_eyes to heterochromia. Although this one is more work, it's more consistent with the other coloring tags and it'll make future tagging better. Either way some work is needed and simplest isn't always more accurate

As for the implications and other aliases, these would make things so much neater and consistent.

Rainbow_Slash said:
I think the multicolored eyes> heterochromia implication should stay as it is quite literally discoloration of the eyes as you said.

Heterochromia is technically the condition of having one eye that's one color and the other eye being another color.

GreyMaria said:
Heterochromia is technically the condition of having one eye that's one color and the other eye being another color.

Yes, therefore if they are both the same color then they should be put with something else. The main question is; is multicolored eyes referring to one eye different from the other or multiple colors in each eye but both eyes match?

Well, you both are correct since e6 uses heterochromia when referring to eyes of a completely different colour, though the actual definition includes an eye that is different from itself (partial heterochromia)
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Rainbow_Slash said:
The main question is; is multicolored eyes referring to one eye different from the other or multiple colors in each eye but both eyes match?

For the most part it seems to be the latter, such as in the last 2 posts from the OP

And since heterochromia exists to describe the former, how about using multi-colored eyes to describe the latter?

titaniachkt said:
Well, you both are correct since e6 uses heterochromia when referring to eyes of a completely different colour, though the actual definition includes an eye that is different from itself (partial heterochromia)
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For the most part it seems to be the latter, such as in the last 2 posts from the OP

And since heterochromia exists to describe the former, how about using multi-colored eyes to describe the latter?

I like that solution. I really wanted these two different.

So then it's-
Heterochromia-one eye different from the other
Multi-colored eyes for eyes matching but multiple colors therein.

On a related note, there's also the issue of all the different coloured *_body/fur/scales/skin tags

i.e

*_body (About 80%+ of the *_body tags are attributed to mlp posts. You can see for yourself by searching for *_body -my_little_pony )
*_fur
*_skin
*_scales

How about making the *_body tag an umbrella tag, and implicating the respective coloured body types to it?

If you spot any that were missed, feel free to say so & I'll add it in

Rainbow_Slash said:
I like that solution. I really wanted these two different.

So then it's-
Heterochromia-one eye different from the other
Multi-colored eyes for eyes matching but multiple colors therein.

You got it

I have been thinking of this too and coming across images where I don't know if it would be considered fur, scales, or what. This sounds like a good way of avoiding having to use "blue" or "green" alone.

Also the species being tagged should silence the complaints of "I don't want to mix all the types of skin/feathers/fur"

*Necromancy*

Turns out that there are a number of colour tags in use for many, many things, and there should be some kind of consensus for all of these before anything official's done with them

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Rainbow_Dash said:
I have been thinking of this too and coming across images where I don't know if it would be considered fur, scales, or what. This sounds like a good way of avoiding having to use "blue" or "green" alone.

Also the species being tagged should silence the complaints of "I don't want to mix all the types of skin/feathers/fur"

Most definitely; the *_body tags are populated and varied enough (i.e. not just on mlp posts) that using them in lieu of raw colour tags (blue, green) seem acceptable

And all those proposed implications of *_body -> *_fur/feathers/scales are still open for consideration
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In addition to the body colours (not forgetting *_skin)

You can find most of these by searching for your favourite basic colour (e.g. red_*) here and ordering by count

Are all these recognized tags? Should they be? If not, why?

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Oh, and don't forget there's a (very much WIP) tag group:colors wiki page to document all of the colour tags being used on e621
If you have an idea/suggestion about what to include in that wiki page, or any of the tag groups, or even suggesting a new tag group, feel free to mention it in the Tagging Projects topic