What's the deal with male lip paint?

[PNGwynne]

What are the variations on male figs with painted lips (Trek, Merry Men, Knights)?

Are they exclusive to t1 heads? I've seen some with pink tones, & some that are kind of tan...

And I've never seen a Galahad/Will Scarlet with painted lips...

What lines featured this detailing?

Thanks!

[josephcardone]

I know that the earlier Star Trek had pink paint only on T1 bodies because I have been looking for a few. The Klingon has red - again only on early T1.

[Jordiway]

Some 12' figures had painted lips such as Killer Kane I always hated this and always used something to remove it.

[cjefferys]

Yep, for the Trek, it's only on T1 bodies, only the very first released figures had painted lips, it was changed very early in their production run. Still looking for a red lipped Klingon to complete my set, I don't care how silly he looks (the paint on the crew members is much more subtle).