Is it really impossible to have gradient without banding?

Question

I am struggling to create a gradient without banding. I have watched all the videos on YT and tried: Bluring all kinds, Noise, Dither,bit depth, Brush and doing the gradient in Illustrator.

Everything fails and I can always see the banding.

The background color I use behind the image: 050b3c

Answer 1

Noise and dither usually yield quite good results. There's a couple of things that may make “banding” more apparent:

• “start” and “stop” colors
• gradient size (banding becomes more apparent when “start” and “stop” points are getting farther from each other—gradient have to be “projected” on more samples with the constant number of available brightness values),
• miscallibrated/poor quality monitor (have you tried to view your gradients on different monitors?),
• reduced “per-channel” color resolution in system settings (seems unlikely nowadays since most systems use 32 bps settings, but still a possibility),
• “wild” video card gamma settings (e.g. in “video card control panel” or gamme loader like Adobe Gamma Loader),
• too “agressive” monitor profile (again view-on-other-monitors test should provide some hints about it),
• reduced bit depth of an image.

Also it would be useful to know what your target device is. There's a difference how much you can “spread” your gradient whether you're targeting print (what kind of print also matters e.g.: screens like AM, pseudo-stochastic, stochastic) computer monitors or mobile devices displays. It also makes difference then wether you use raster graphics or vector graphics.

Bottom line is: this is quite complex subject :).

Answer 2

Yes, it's possible to create high quality gradients. There's lots of factors to take into consideration though.

• Photoshop doesn't and can't dither on the alpha channel. You're better using solid colours, if possible. Also, try to avoid layer opacity. Create the gradient using the exact colours you need.

• There can be some cumulative rounding errors if your image editor is using 8 bit per channel colour depth. The best quality way to generate a gradient that's created from several layers (with blending modes and opacity at play) is to render at a higher bit depth, then dither down to 8 bit per channel, if possible. Photoshop can do this. If you want an all solid gradient created from one layer, 8 bit per channel is ok (16 bit is only handy when there's layer blending involved).

• Dithering is really, really important. (See previous point.)

• Don't use Illustrator. It's 8 bit per channel and doesn't dither.

• Image scaling will ruin the good work dithering has done, so you'll need to create the image at the correct size from the outset.

• Most laptops have 6 bit per channel displays with some animated dithering tricks to make things appear better. Obviously you're fighting the display and smooth results may not be possible, due to the display. The new MacBook Pro with Retina display is a notable exception — it has a 24 bit IPS display.

• As thebodzio has suggested, other OS-level processing can mangle things as well.

• If you do use 16 bit mode in Photoshop, test it against 8 bit mode. There's certain circumstances where 8 bit mode looks better and other circumstances where 16 bit mode is better. Basic rule of thumb: If you have one gradient, use 8 bit with dithering. If you have several layers and gradients using opacity, use 16 bit mode.

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Looking at your image, it seems like there's some other destructive conversion happening. Are you using Save For Web? Do you have Convert to sRGB turned on? If so, turn it off (it's the easiest way to ruin the quality of your images, and make destructive colour changes at the same time).

Answer 3

A very basic difference on creating gradients is using the Gradient Layer which has a dither option built in (Layer>New Fill Layer>Gradient) and stays adjustable. From here on you could convert to smart layer and add whatever effects you need to improve further, but it gives you a much better starting point.

Answer 4

Marc Edwards writes that "Photoshop doesn't and can't dither on the alpha channel." If so, you might be able to fake it by creating a dithered gradient from white to black and then making the white transparent. Alas, it's been a while since I used Photoshop, but the general idea would be something like this:

1. Create a 16-bit gradient from black to white.
2. Dither it down to 8-bit.
3. Create a solid black layer and add a layer mask to it.
4. Copy the dithered gradient into the layer mask (and invert it, if needed).
5. Apply the layer mask to get a nicely dithered gradient from black to transparent.

(Yes, I know this is more of a comment than an answer, but it got too long to fit into the comment box.)

Answer 5

I've found a similar problem in Illustrator (which doesn't even have a "dither" option for gradients). It sounds a bit crazy, but I get around it by applying a "glass" filter, which can approximate dithering with the right params.

I use:

• Distortion: 2 (this is dependent on the side of your bands).
• Smoothness: 1
• Texture: Frosted (the noisiest built-in texture)
• Scaling: 50%

In Illustrator, this introduces white specks at the edges of your object, which you can fix by using a clipping mask.

Results? "Dithered" one on the right. It does add a bit of a noisy texture, but I think it's better than the bands most of the time.