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

Post by Joel_Mckay » Tue, Aug 04, 2026, 5:49 PM UTC

iwontberude wrote: post #55

Joel_Mckay wrote: post #44

Earlier quoted context omitted.

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…

> People only turn yellow if they have kidney or liver damage. This is not true. Roughly 5% of people have Gilbert's Syndrome which is genetic, metabolic abnormality where the bilirubin from dead blood cells are conjugated slower than the baseline patient leading to yellowing of the skin. It is not due to liver damage or disease and is a benign condition. Not to mention there is carotenemia from eating too many carro…

Post by zild3d » Tue, Aug 04, 2026, 5:56 PM UTC

s1mon wrote: post #54

It's always entertaining to try to understand these things from first principles. Color and skin color in particular are very complex things to measure and model. It's not just a physical quantity, it's also a matter of human perception based on lighting and a host of factors. It seems like some work was done to research existing approaches, but I don't see any reference to Pantone Skin Tones [0]. Without intending t…

Post by HanClinto » Tue, Aug 04, 2026, 5:58 PM UTC

dr_scully wrote: post #48

GolDDranks wrote: post #26

Earlier quoted context omitted.

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 separ…

Post by dr_scully » Tue, Aug 04, 2026, 6:15 PM UTC

HanClinto wrote: post #65

dr_scully wrote: post #48

Earlier quoted context omitted.

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 separ…

This brings up an interesting topic of atypical compounds that can visibly affect skin coloring -- whether temporary or more long-lived (such as elevated methemoglobin levels in the Blue Fugates of Kentucky). It's fascinating to learn that melanin and haemoglobin are the two primary factors (and cover the vast majority of cases), but I'm curious how many other illnesses / disorders can produce compounds with visible…

Post by rsynnott » Tue, Aug 04, 2026, 6:21 PM UTC

andai wrote: post #7

Nice. Most of these colors look right to me, but I'm also seeing green, blue and purple? If you're curating colors from the space manually then it's not a problem. "Only realistic colors" would be a different problem. And I'm not sure if there's a way to solve that problem without excluding some real colors too. (Maybe if the colour selector was a different shape? I don't know much about color spaces.)