Problem when printing shadows and gradients

Hello:

I have a problem with images and shadows over a white backgroung. When I send these images to print (in commercial press CMYK), the shadows doesn't show all the gradient from the white color smoothly, instead, it prints with rough edges. It seems that when they make the plates, the machine doesn't read the lighter tones and starts reading from certain amount of color. It has happened sometimes with gradients also. Is there any way to avoid that?
Thanks in advance.

Frank :confused:

I think the problem you have is reffered to as "banding". I want to be able to tell you exactly what to do to fix it, but Im a bit unsure and dont want to lead you astray. But I am positive what you need to look up, or talk to your printer about is "banding". Hope that helps a bit.

Yes, I think that "banding" is the problem I'm having. Thanks for the interest.

what is 'banding' exacly ? can you explain ?

try to avoid color from below 5% and more than 95%

Ask your printer about your papers dot gain. This can lead to banding in gradients.

Hiya Frank,
Here are a couple of tips re: banding.
If you are creating a blend From a colour to black, use 40>50%CMY + K. Don't just use black by itself.
Adding a little (3-5 pix) noise and then blurring will help break up the banding.
Level 3 Post Script RIPs usually cope with blends and prevent this problem.

If you need a sample of how this works, let me know
Hope this helps, Cheers Al. ;)