3

In Photoshop you can add Dither to Gradients. I understand what dither is but when I apply dither to my gradient I can see no difference. What exactly does dither do?

Improve this question
2
  • Dithering is practically imperceptible unless you're working with a gradient on a very small raster image.
    – Scott
    Commented May 4, 2012 at 0:24
  • @Scott not true. Dithering is important in a variety of cases.
    – Dominykas Mostauskis
    Commented Jul 17, 2014 at 16:08

1 Answer 1

Reset to default
5

Dithering is a technique used in computer graphics to create the illusion of color depth in images with a limited color palette (color quantization). In a dithered image, colors not available in the palette are approximated by a diffusion of colored pixels from within the available palette.

Source: Wikipedia article on Dithering

Without dithering you would often see color banding in gradients and smooth color transitions. Color banding is where you can see the boundaries of color when you really shouldn't. A good example image is here. The image in the top right corner is heavily banded, just below it's been improved with dithering.

If you draw a very light gray -> white gradient in Photoshop with and without Dithering, you will likely see the difference. You may need to zoom in. But anyway, with the millions of colors we have on our displays these days, the difference Dithering makes is often imperceptible.

Improve this answer
6
  • I hope this answers your question. You did say you understood what dither is, so sorry if any of this is redundant!
    – hamstu
    Commented May 3, 2012 at 22:50
  • Thanks for the information and it is okay if it is a bit redundant, others will see this and may not know.
    – L84
    Commented May 3, 2012 at 23:18
  • 1
    The "Noise" parameter you see in, e.g., glow and shadow effect dialogs is closely related, and has the same purpose. Dither and noise don't eliminate quantization artifacts; they just make them not noticeable.
    – Alan Gilbertson
    Commented May 4, 2012 at 6:09
  • 1
    It's also worth noting that banding may be an issue in print even if a particualr gradient looks smooth on screen.
    – e100
    Commented May 4, 2012 at 16:09
  • More specifically, dithering is usually for PRINTED gradients. The improvements are much more noticeable on press.
    – DA01
    Commented May 4, 2012 at 18:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.