: Why grainy blur when layering blurred things? Why is it that when you layer a blurred dot over and over you begin to see the "grains" of grayscale? Is there a fix? Higher resolution? Gamma

@Sarah814

Think it as the blackness (0...255).

Have a white background and an empty layer. Paint a black dot onto the empty layer and blur it.

After the blurring the blackness is just in the middle nearly 255 or even full 255. Further away the blackness decreases. Far enough it's zero, little closer maybe 1, then 2, then 3....When you pile thislike patterns, the blackness cumulate. Zero stays zero, but the rest:


2 layers, the rings have blacknesses 2, 4, 6,...
3 layers, the rings have blacknesses 3, 6, 9,...
4 layers, the rings have blacknesses 4, 8, 12,...


The differences increase as you add more copied layers. Very soon the borders are clearly visible.

Do the same with 16bit resolution. I tried it. No rings was possible to see with 50 layers. Then I stopped. Probably the slightest visible ring would have taken 500 layers.

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