What a toxic comment. He is simply referring to the technical difficulty associated with darker skin tones. Of course we should strive for making it applicable for everyone. Sometimes physiological variations get into play; sometimes this means a method isn't adequate, or you can use different methods for different persons.

Darkness is the property of absorbing light.

The technique of analysing light which penetrates the skin, then reflects, then penetrates the skin again on the way out? Easier with skin that allows more light through.

You can turn up the light source to make up for the loss due to skin pigmentation, though this can require a very bright lamp for particularly dark skin.

From the commenting guideline:

>Comments should get more thoughtful and substantive, not less, as a topic gets more divisive.

>Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

Please refrain from commenting like that on other threads.

The poster said it needs good i.e. bright lighting to work. How is it contentious that it would be harder with skin that reflects less light?