large format printer

Banding issues in gradients  can be a problem in offset print and large format printing. We usually run into this issue when we’re printing large format for custom banner stands or offset printing for full colour, professional brochures . The issue tends to be more prevalent when gradients are created in Illustrator  for output to large format printers.  Certain colour schemes also can be more prone to banding such as dark blue to light blue. If you’re creating gradients in Illustrator, Photoshop or InDesign you’ll need to make sure there are no banding issues before your artwork is output to final print.

As an offset and large format printer we always watch for banding problems prior to printing. If you discover banding issues the following technique may help reduce or eliminate the problem.

Banding Lines

An example of a gradient with banding issues.

Using Adobe Photoshop the first step will be copy your gradient onto a new layer.

create layer

Copy your gradient on to a new layer.

Select the layer we just copied. We will now go the filter drop down menu and select Blur | Gaussian Blur.

Gaussian-Blur

Click the filter drop down and select Gaussian Blur.

We’re now going to add gaussian blur to the gradient; the amount you can add will depend on the colours that you are using in your gradient. You can refer back your original gradient which is on its own layer to ensure the colour isn’t changing to drastically. You may find you will have to strike a compromise between the original colour and the amount of banding that shows. When you’ve achieved an acceptable balance click OK.

Now click on your layers palette and create a new layer called Overlay, change the mode to overlay and check  ‘Fill with Overlay-neutral colour (50% gray).

Overlay

Adding a new layer for overlay.

With your new Overlay layer selected click the Filter drop down and select Noise | Add Noise.

Add Noise

As with Gaussian blur the amount of noise you can add will vary depending on your colour scheme. In general you will be adding a small amount of noise (.1 to 3%) ; too much noise and you will see a distinct texture.  Under ‘Distribution’ select Uniform.

Adding Noise

Adding noise to your overlay layer.

You will find that you’ll need to play with different combinations of the above to achieve good results in printing gradients. Every colour scheme will react differently to these adjustments. You should be able reduce or eliminate most banding with this technique as shown below.

N0-Banding

An image with no banding.