KB194119361: Pack Proof - How to avoid banding in gradients when proofing jobs with Pack Proof

Summary

This KB describes how one can avoid banding in gradients (a.k.a vignettes) when making proofs with Pack Proof.

Symptoms

Banding can be caused by various reasons but one important reason is related to the fact that 8-bit data is generated for proofing. The amount of steps/tints available to proof a gradient going from 0% to 100% is limited to 255 for 8-bit digital files.

That's why small "jumps" can occur in case of large gradients. This is what is causing the vertical/horizontal lines in a gradient (a.k.a. banding).

Workaround

To avoid the banding, add noise to the input file by using the Automation Engine "Export to PDF" ticket:

1. Select the input file (Adobe or Normalized PDF).
2. Open the "Export to PDF" ticket.
3. Click the Rasterize tab:
   • Rasterization resolution = the printing resolution (use the maximum in case of an asymmetric resolution)
   • Enable the option "Convert vignettes to image"
   • Vignette noise = 5%
4. Save these settings as a custom ticket and add this ticket before the "Proof for Contract Approval" ticket.