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Not sure if this is a Physics question, but...

Why is it easier for inks to show up on white paper than on black?

You can get "special" inks which print solidly on top of black surfaces, but your common stock will make black paper look as if it's merely tinted, whereas the colours show up boldly on white.

It's confusing to me for two reasons.

Firstly, human sense organs respond approximately logarithmically. As in, a drop in light intensity from 100W to 99W will be less noticeable than a drop from 10W to 9W. This would lead me to predict, since colours are defined by the wavelengths they subtract from a white source, that the lower baseline quantity of light from a black surface would make the coloured inks on top of it seem bolder against the background than the same intensity-differential-per-wavelength against a higher intensity background.

Secondly, if you start with an RGB colour which is (100,100,200) units (i.e. blue-grey) and then add intensity uniformly to, say, (1100,1100,1200) units, then the proportions are closer to unity, i.e. the colour desaturates. If the explanation for my question was "the ink allows some white light through which bounces off the paper and returns, making the colour brighter", then I would expect inks to desaturate when you shine brighter lights on them. But this doesn't happen.

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closed as off-topic by ACuriousMind, user36790, CuriousOne, Bill N, Martin Apr 28 '16 at 10:22

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  • "This question appears to be about engineering, which is the application of scientific knowledge to construct a solution to solve a specific problem. As such, it is off topic for this site, which deals with the science, whether theoretical or experimental, of how the natural world works. For more information, see this meta post." – ACuriousMind, Community, CuriousOne, Bill N, Martin
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  • $\begingroup$ The answer may also just be convenience and habit - historical inks were always dark (mostly due to graphite being present): en.wikipedia.org/wiki/Ink#History. The rest then is biology (perception) and engineering (could one change now?) $\endgroup$ – Martin Apr 28 '16 at 10:22
  • $\begingroup$ black and colored inks can be made from either pigments or dyes, but a white ink intended for use on black paper can only be done with a pigment- and pigmented inks are inherently more difficult to engineer. $\endgroup$ – niels nielsen Oct 25 '18 at 22:48
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I guess it's because it's easy to add all sorts of materials that make the surface absorptive for a broad spectrum such as for visible light. Then it'll look black. To write on a black paper you need something that really covers the paper adding material which reflects all visible light, causing a white color.

As far as the human eye and its dynamical range is concerned, I guess your point is already included in our perception, since gray perception is much more black if measured with a light source and a photo detector.

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