Will my color gradients have banding?
Photoshop is IMHO the greatest app ever invented. I think the Knoll brothers are deserving of a Nobel prize for app creation. Photoshop is the best thing to happen to comics since Jack Kirby. I even once wrote an article published in a major comics magazine that lovingly detailed the history of Photoshop in comics. So please do not think this post is a knock on Photoshop. It isn’t. I’m simply pointing out a known deficiency in the program.
Large Gradients. Photoshop still does not handle large color gradients without producing at least some banding.
This is the one nut that Photoshop engineers have never been able to crack. It’s improved a bit. But even in CS4 you will still see some banding in areas with large gradients. Zoom in. You’ll see it on the screen. It’s unmistakably there.
So if you have submitted a job to us that has large color gradients created in photoshop that inherent banding will find its way into our print. If colors at the extreme ends are close then the banding may be very subtle … maybe even hard to detect at print resolution. But if you have a lot of variance from one end of your gradient to the other, then you will see some banding. It’s unavoidable, I’m afraid.
best to do a slight Gaussian blur or air brush over to ‘cover’ the bandings.
What of other digital graphics editors? Corel, Gimp, etc..? I’m guessing it’s the same deal across the board, but any particular insight?
Those are fine as image editors, but I think Photoshop is in a different league altogether. It’s the best in spite of its occasional shortcomings.
Even on a traditional printing press, banding is inevitable in large gradients. With digital presses gradients can be better or worse depending on the RIP. But, since Photoshop files are raster files to begin with, the gradations output better than from any other program. A good rule of thumb is to apply as many steps in your gradient as possible. Start out at 100% and instead of going to white, go to 5% of the color. Single color gradients output with less hard lines than going from color to pure white.
On large-format printers (mainly inkjet) we always add a very slight noise filter to large smooth gradients. It seems to help the RIP figure out a way to interpret a wider variety of dot sizes, so you don’t get distinct stair-steps in the gradient. 1% uniform noise should do the trick. Selecting just the smooth areas can be tricky, though, because you don’t want to noise solid regions, complex textures, lineart, etc.