When they’re created properly, gradients are a great way to add flair to any design. When created improperly, banding can occur. Banding is visible when each available shade covers an area large enough for you to see individual strips of that color.
Why does banding happen? All output devices are binary, and therefore cannot print shades of ink or toner. Instead, various sized dots (AM screening) or uniform collections of dots (FM screening) are used to simulate shades of gray. These dots are placed in varying sizes (AM) or amounts (FM) side by side to create a gradient. Generally speaking, if the individual bands of dots are more than 1/32 inch wide, the eye sees them as distinct strips, and the illusion of a smooth gradient is lost.
Below are some techniques you can apply to reduce or eliminate the appearance of banding in gradients:
- Use a gradient that changes at least 50% between two or more process components.
- Increase the percentage of change in the gradient.
- Add a Gaussian Blur or Noise filter in Photoshop.
- Avoid creating gradients that blend from very dark colors to white.
- Use shorter gradients. Generally, gradients in digital printing should not exceed 7.5 inches in length.