GCR - Friend or Foe?

[mglouis]

Hi Jud,

I have only noticed banding problems I would attribute to reseparating images in lighter tones along gradients and in all cases the customer art was not perfect. Alwan has a control for grid points so you might try lowering the resolution of the profile with the goal of smoothness over accuracy.

The nature of moving tonality from CMY over to the black plate may be exposing problems in your black unit. Pushing the k start up away from zero into the mid tones seems to help highlight banding in our case for whatever reason.

Banding may also be caused by CTP curves. Steep curves in highlights or steep differences between two overprinting colors are problems areas to keep an eye on. As an experiment if you have the luxury of a press test you might try the same files that gave you a problem on uncalibrated plates to isolate their contribution to the problem.

Matt Louis