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I've noticed that we have so-called 'black' clothes everywhere, I haven't seen so far any piece of clothes that would be really black, it's always some kind of lighter black.

For instance, if you take a 'black' shirt then put some water on it, the stain will look even darker.

Why is it so hard to make (nearly) totally black clothes?

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    $\begingroup$ What material do you know that absorbes absolutely all visible light, reflecting nothing at all. "Nothing" is a rather small value. The same issue goes for white too. Some material would have to reflect all visible light. $\endgroup$ Sep 5, 2014 at 14:26
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    $\begingroup$ @OlinLathrop Well, I don't really know how good we are at creating materials that absorb a lot of light and can be used in clothes :) which is why I made this question. I thought those kind of clothes might exist for specific branches (military, ...) $\endgroup$ Sep 5, 2014 at 14:27
  • $\begingroup$ I posted an answer to a question very similar to this on another site recently. It's not really Physics.SE quality but you might find it interesting: twistypuzzles.com/forum/viewtopic.php?p=323898#p323898 (EDIT: I just realized you can't see the images in the post. I'll think about how to clean the post up and make it an answer here.) $\endgroup$ Sep 5, 2014 at 17:04

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This is a nontrivial problem in materials science. People have done a lot of work both with different materials and different surface structures to create "ultra-black" absorbing structures for use in optical systems.
A big part of the problem is the statistical nature of photon absorption. There's only a certain percent (<100) chance of absorbing a given photon with a given material. Changing the macro structure to force a large number of reflections increases the net probability of absorption.

Oddly enough, the military does not want perfect absorption: it's just as easy to detect a "hole" in the environment as a "beacon." Camouflage is designed, roughly, to have a reflective parameter indistinguishable from the intended local environment.

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    $\begingroup$ Carl this doesn't really answer the question. $\endgroup$ Sep 5, 2014 at 17:05
  • $\begingroup$ @BrandonEnright ok, what do you interpret the question as? $\endgroup$ Sep 5, 2014 at 17:44
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    $\begingroup$ I think I interpreted the question the same as you. But your answer basically says it's non-trivial and then you provide a bit about photon absorption stats and then finish with a only partially related anecdote. You didn't mention anything about reflectivity or how not all frequencies are easy to absorb equally. $\endgroup$ Sep 5, 2014 at 19:05

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