The author posted a question in Science, Technology, Languages
When the first mirrors from China appeared in Europe, they caused a great furore and cost a lot of money. But artisan people? and got a better answer
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If you etch a drawing on the surface of polished glass with weak hydrofluoric acid, you get indentations on it. Very small depressions are unnoticeable to the eye, but the sun bunny will show dark spots as the pits will work as scattering lenses Another question, where could the ancient Chinese have gotten hydrofluoric acid? PS I'm not sure the Chinese made glass mirrors 500 years ago, more likely metal mirrors. And how do you make microroughnesses on a metal mirror, you can think of dozens of ways?
Response from 0[+++++]
If you etch a pattern on the surface of polished glass with weak hydrofluoric acid, pits will form on it. Very small pits will not be noticeable to the eye, but dark spots will be visible on the sun bunny, because the pits will work as scattering lenses. PS I'm not sure the Chinese made glass mirrors 500 years ago, more likely metal mirrors. And how to make microroughnesses on a metal mirror, you can think of dozens of ways.
If you etch a pattern on the surface of polished glass with weak hydrofluoric acid, pits will form on it. Very small pits will not be noticeable to the eye, but dark spots will be visible on the sun bunny, because the pits will work as scattering lenses. PS I'm not sure the Chinese made glass mirrors 500 years ago, more likely metal mirrors. And how to make microroughnesses on a metal mirror, you can think of dozens of ways.
Response from 0[+++++]
I give up, what's the secret?
I give up, what's the secret?
Response from 0[+++++]
Cool, man. Tell me the secret.
Cool, man. Tell me the secret.
Response from 0[+++++]
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Response from 0[+++++]
Take an ordinary pair of glasses and see what kind of shadow they give off. Completely clear glass already gives a BLACK shadow from a couple of meters away! I suspect that the secret of Chinese mirrors is about the same. There has to be a slight relief, on the order of hundredths of a millimeter, which creates a FLAT surface of reflection, best of all it should be convex. The light reflecting from such areas gets some divergence of the beam, which at small distances - when you look at your face - is unnoticeable, but at a distance of several meters, on the wall of the house, only light from the flat part of the mirror comes without losses. The light reflected from the convexity, just has time to scatter over a larger area, so you get a shadow there is actually just less illumination It can easily turn out that the effect is even more subtle - for example, one thing when you consider, again, your own face, another thing - when you reflect direct sunlight. The surface flatness may be due to heating - after all, a bronze mirror has a reflection coefficient far from unity, it must heat up in the sun.
Take an ordinary pair of glasses and see what kind of shadow they give off. Completely clear glass already gives a BLACK shadow from a couple of meters away! I suspect that the secret of Chinese mirrors is about the same. There has to be a slight relief, on the order of hundredths of a millimeter, which creates a FLAT surface of reflection, best of all it should be convex. The light reflecting from such areas gets some divergence of the beam, which at small distances - when you look at your face - is unnoticeable, but at a distance of several meters, on the wall of the house, only light from the flat part of the mirror comes without losses. The light reflected from the convexity, just has time to scatter over a larger area, so you get a shadow there is actually just less illumination It can easily turn out that the effect is even more subtle - for example, one thing when you consider, again, your own face, another thing - when you reflect direct sunlight. The surface flatness may be due to heating - after all, a bronze mirror has a reflection coefficient far from unity, it must heat up in the sun.