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Show HN: Simple algorithm and color space to generate diverse skin tones

toneyalexander.github.io

41–50 of 129 posts

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#41
Skin tones are particularly difficult to pin down, besides the pigmentation there are two effects at play: 1) sub surface scattering (light goes thru and bounces under the skin a bit) and 2) some infra-red emission (the responsible for making some people appear magenta on digital photography)

So even when you get the palette right, to paint it like a believable material in a convincing way is still super hard!

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#43
post #40

Love it! I was looking at this a little while ago, and used some of The Pudding's data on makeup/foundation shades ( https://pudding.cool/2018/06/makeup-shades/ ) and plotted it into the Oklab colorspace ( https://observablehq.com/@55th/foundation-shades ). The shades form themselves into that same crescent as seen in the article.

Woah I LOVE both of these! When I get a chance these are 100% getting linked from the writeup.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#44

Earlier quoted context omitted.

If you look at my doctoral thesis, in fact skin colour can be parametrised using melanin and haemoglobin concentration; which it means it is indeed (roughly) two dimensional. This allows you to invert the colour of a pixel and identify someone’s chromophore concentration. This is based on previous work of others cited in the thesis. https://discovery.ucl.ac.uk/id/eprint/10093345/

I've heard that the so-called "yellowish" skin color that non-tanned East Asians tend to have, is due to relative abundance of subcutaneous fat. If that's true, is that captured by the haemoglobin dimension or is it a yet another degree of freedom?

All skin is slightly translucent, and color/tones forms a gradient across the surface of the skin. Your upper cheeks and forehead are usually slightly reddish, and the chin/neck are slightly bluish.

People only turn yellow if they have kidney or liver damage. However, some distinctive features like Lucy Liu's natural freckles are tough to draw right.

We looked around a lot for a procedural texture/shader to help make the project characters look less sickly, and please also consider supporting the persons work if you are able:

https://kuhantilope.gumroad.com/l/ultimate-skin

Best of luck =3

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#46
Not my domain though I followed the data science enough to nod as if I really followed it,

but this is just lovely and inspirational work. A unique marriage of hacking in the celebratory sense, thoughtfulness, and meaningful contribution. Outstanding.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#47
post #34

Earlier quoted context omitted.

If you look at my doctoral thesis, in fact skin colour can be parametrised using melanin and haemoglobin concentration; which it means it is indeed (roughly) two dimensional. This allows you to invert the colour of a pixel and identify someone’s chromophore concentration. This is based on previous work of others cited in the thesis. https://discovery.ucl.ac.uk/id/eprint/10093345/

Oh goody, an expert in a question I've always wanted to ask. Once upon a time, I encountered a sort of interactive museum book called "Earthsearch". One of its "exhibits" was a color wheel, made of two spinnable pieces of tinted acetate, that purported to be able to generate any skin tone. I suppose this is three degrees of freedom, since for any position of the two wheels you could access a range of colors around th…

Oh man, that's a blast from the past, I think I had that book! Was that the one with an aluminum cover?

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#48

Earlier quoted context omitted.

If you look at my doctoral thesis, in fact skin colour can be parametrised using melanin and haemoglobin concentration; which it means it is indeed (roughly) two dimensional. This allows you to invert the colour of a pixel and identify someone’s chromophore concentration. This is based on previous work of others cited in the thesis. https://discovery.ucl.ac.uk/id/eprint/10093345/

I've heard that the so-called "yellowish" skin color that non-tanned East Asians tend to have, is due to relative abundance of subcutaneous fat. If that's true, is that captured by the haemoglobin dimension or is it a yet another degree of freedom?

We used the approximation that the hypodermis was a perfectly white reflector; so the thickness wouldn’t matter. The collagen fibrills scatter light in such a way to create a yellower tint. So a person’s skin might appear this way in the absence of melanin and haemoglobin. I’m not an expert on population statistics, and so cannot give an opinion on specific skin types. Everything was based on ranges.

There is a separate effect of increased bilirubin content, that would appear if someone was ill.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#50

Not my domain though I followed the data science enough to nod as if I really followed it, but this is just lovely and inspirational work. A unique marriage of hacking in the celebratory sense, thoughtfulness, and meaningful contribution. Outstanding.

Wow what a touching compliment, thank you so much!!
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