Gradient Banding: Causes and Solutions

Gradients can sometimes present challenges, such as visible steps, inconsistent color transitions, or differences between how they appear in PDFs versus on-screen. 

This article outlines common causes of gradient-related issues and provides solutions to help you achieve smoother gradients in your prints. 

Rendering Intent

The rendering intent used can significantly affect gradient appearance. If you are experiencing issues, try switching from colorimetric to perceptual rendering intent.

For raster gradient files, the software will automatically detect the color spaces via the Colors interface (for input and output options). You can verify or change this here:

For vector files with Spot colors, you must verify the rendering in the Spot colors interface:

ICC Profile Accuracy

The accuracy of the ICC profile is crucial. If color shades are not smooth or if linearization is inaccurate, it can lead to visible steps in gradients. To verify this, use EasyMedia to print gradient test targets after the linearization step.

Vector vs. Raster Files

Vector files default to an 8-bit rendering engine, which provides 256 steps. This can result in visible stepping in large gradients. Darker steps may be related to the rendering intent or ICC profile accuracy. Starting with CalderaRIP V9.20, you can select a 16-bit rendering engine for smoother gradients. To enable this:

1. Double-click the printer icon.
2. Click on the Colors icon.
3. Go to the Miscellaneous tab and enable 16-bit rendering.

     Warning

   By changing this setting, there could be an increase in job ripping time by approximately 150%.

   

For raster gradient files, the 8-bit engine typically produces smoother gradients since it does not perform the same calculations as the vector engine.

(Global) Color Management settings

The Adobe PDF Print Engine Configuration allows you to change the behavior of the Adobe PDF Print Engine in different ways. With the first field, you can select either "Caldera" (by default) or "Adobe" as the CMM (Color Management Module) to use:

Both options produce the same colors in most cases and have the same sub-functions, however, under certain conditions, the Adobe setting may yield smoother gradients.

To access and change the global color management settings, go to the Application bar > Configuration or Special menu (in older versions) > Adobe PDF Print Engine.

Starting with CalderaRIP V9.20, you can also choose if gradients should be processed as images or vectors:

Printer-Specific Settings

Factors such as print mode (CMYK vs. CMYKcm), printer resolution, and other printer-specific settings can impact gradient behavior. Low resolutions often produce poor gradients, while lighter colors can help create smoother transitions in lower percentages.

Color Management

Ensure that the input and output colors (via the Colors interface) are fully enabled and correctly set up, as gradient issues can arise from improperly preserved colors:

General Recommendations

If you have a recent CalderaRIP, make sure to keep your software and drivers up to date by regularly checking CalderaDock. You can view the version of CalderaRIP directly in the splash screen that appears at startup or by clicking on the Help menu > About this software.

By following these guidelines, you can effectively address gradient issues for high-quality prints. If problems persist, feel free to contact support for help.