Jagged gradients (fountain steps)

Hi there

In CMYK mode gradients arent always very soft.. one can easily detect transitions that werent suposed to be.
Can anyone help me on getting cleaner gradients for printing purposes
Thanks a lot

By "fountain steps" I'll assume you mean "banding" There are a couple of thing I do to prevent/lessen banding.

The solution usually involves adding noise to the gradient.

In situations, where the professional printer is having more problems with banding than my own laser printer can replicate, I usually add a temporary adjustment layer to my Photoshop file (Curves or Levels) and ridiculously crank up the contrast. This will display a worse case scenario of banding on my screen and I can then create another layer, fill it with a 50% grey, set the blending mode to overlay and then add noise until the banding is reduced to a usable level. Then turn off the adjustment layer and see if the best case scenario is usable. If not you may need to redo the noise layer with a little bit less noise.

Also if I HAVE to, I try adding noise to individual channels. Generally the blue channel is already really grungy so I'll add a little noise to the yellow and look at my gradient (in the described manner above) If it helps I keep it and move on to the next color channel magenta. At lower screen values black can also be a problem in a banding situation.

Hi guys,

We face this problem alot from supplied files. Here's a couple of fixes. Not sure of which printing process your are using, so the answer is made for generality.

1. If offset, ask your printer to adjust the screen angles on the film. You can do this in photoshop, illustrator and corel if preferred, but generally it is best done by the printer. Who knows, they may have a particular image setter or blue printed press etc. Also, ask about press speed and if press temp is achieved.

2. Artwork Issues. This is generally the best fix.
Photoshop: When making a file with gradients, blends etc, go to the Layer Property and right click, brings up the 'blending options default dialog'. Adjust as you see fit.
Photoshop: Create the file at above 300dpi and Check on DITHER.
Raise your Fountain Steps above 256.
Illustrator: Raise Banding above 600
Corel: Raise Fountain Fill (unlock the little padlock and manually type in 600).

3. Also remember, it's ink. Commercial applications may not be able to lay down less than 3% ink coverage. So a printed edge may appear. Design accordingly and allow for C, Y, M, K loss.

4. Digital Printing, check to see nozzles are clean.

5. We find this the best fix for really large prints, like signs etc. Rotate your canvas between 0.5 and 1.5 degrees. This will angle the canvas but make sure any text or logo elements are not rotated. All you want to achieve is a slight pixel manipulation.

6. At the end, you can pre-check by doing a Gamut Check. Gamut check is used for non ink colors. But it gives you a quick visual of any outstanding banding issues that may arise. Not print reliable, just visual.

If your sending flat files out for printing, make sure the eps and fonts are broken apart / converted to outlines.

Hope it helps,
Billy Tea
www.australiasigns.com.au