On: Making noisy SVGs

[itishappy]

It's the same effect! OP may have done this for style, but the effect also happens to hide any banding that may have be present.

[Someone → itishappy]

It may look similar in these high resolution pictures, but it’s different.

With dithering, there’s negative correlation between the noise added to neighboring pixels (if one gets a bit blacker, at least one of its neighbors is more likely to be made a bit whiter).

This adds Perlin noise. With that, I think that correlation is zero or, possibly, positive.

[itishappy → Someone]

That's how good dithering works, but adding random noise is still dithering.

https://commons.wikimedia.org/wiki/User:Gerbrant/Dithering_a...

[coldtea → itishappy]

Not the same. Not in how it's achieved (merely adding grain isn't dithering), and not in the final effect.

Google Images "dithering" for examples of how dithering looks.

[itishappy → coldtea]

It's bad dithering, but it's still dithering.

Random noise gives poor but fast results. Error diffusion is great but slow (pixels are processed sequentially).

My favorite technique is using a blue-noise matrix because it gives great results quickly. Creating the matrix is tricky, but you can do it offline and reuse it.