Creative Chit-Chat

Back when I was even more of a Photoshop novice than I am now, I never thought that I would use the Add Noise filter. I always thought noise was something to be avoided; it is a sign of an ISO setting that is too high, or a bad quality photograph. In digital photography, noise is defined as the unwanted random errors in the signal and appears as graininess or specks of false color (according to Get the Most from Your Digital Camera by Simon Joinson). You can see why I would think adding noise to a photograph would be against my instincts.

However, I have since learned that Photoshop’s Add Noise filter can be used effectively for many useful and interesting results in graphic and web design. First, I will explain the different settings that can be specified with the Add Noise filter, and then the effects that can be acheived with this simple yet powerful filter.

Settings for the Add Noise Filter

There are four distinct settings that can be adjusted in the Add Noise settings box. Here is a simple explanation for each one.

The Add Noise filter settings, explained below.

• Uniform – This is a type of noise distribution that is more subtle and distributes the noise colors using random values between 0 and plus or minus the amount that is specified in the slider. I generally prefer Uniform over Gaussian because it is less harsh, but still provides a nice, subtle texture.
• Gaussian – This is the other type of noise distribution that distributes the noise color values along a bell-shaped curve, and it creates a speckled effect. Gaussian distribution uses a broader range of values than Uniform distribution, which makes it less subtle. I believe the Amount that you specify for Gaussian distribution affects how frequently the “extreme” values of the bell curve appear; for example, if you are adding noise to a neutral gray background using Gaussian distribution, a high Amount percentage will add more blacks and whites than a low Amount percentage.
• Amount – This setting adjusts the amount of noise you are adding, but it is added differently depending on if you are using a Uniform or Gaussian distribution. It ranges from 0.10 to 400 percent.
• Monochromatic – This is a setting that you can turn on if you want the Noise filter to only apply to the tonal elements in the image; it does not add any new colors. I generally prefer this setting to be turned on; I don’t like introducing new colors to my design that weren’t there before.

Effects and Uses for Noise

• Adding texture for grainy, old film texture – In the photograph below, I first gave this picture the grayscale treatment by using the Channel Mixer (which should always be used instead of changing a picture to grayscale in Color Mode). Then, I added monochromatic noise (non-monochromatic would have added colors besides black and white, which is not desirable in this case) with a uniform distribution at an amount that I thought looked subtle but effective. After going over a few areas with the burn and dodge tools, the final product has a nice old, grainy feel. You can also just add noise to a single color fill for texture.

A photograph of my boyfriend and I on Halloween last year that I added the Noise filter to.

• Reducing banding in feathered selections or gradients – This is especially critical for print design. Gradients often look great on the computer screen, but not so great on the page. This is because printers are not able to produce the broad range of values that a computer can. To improve the poor reproduction of gradients for print, you can add noise to the gradient to disrupt any banding, which is the lines that appear in a gradient.

A gradient without noise. Horizontal lines, called banding, are very apparent and will worsen when printed.

This gradient has a very small percentage of noise added to disrupt the banding problem that occured in the original gradient.

• Fake a brushed steel or wood grain texture – Noise is a simple way to make many types of textures. For the example below, I simply added monochromatic noise to a black background, and then applied a motion blur to the noise. I then applied a lighting effect to the brushed steel to make it a little more realistic. The same process can be applied to a brown background to imitate wood grain, or even hair or fur. You can also do this on a photograph for interesting results.

An example of faking brushed steel with the Noise filter.

• Give a more realistic look to heavily retouched areas – If you are retouching something in Photoshop, such as skin, it might be a good idea to add some noise to that area so it does not look “too perfect”. Nobody’s skin is a perfect, even shade, and the Add Noise filter can give a little tonal variety to a retouched area.

If you can think of other ways to use the Noise filter, please leave a comment below!

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