One of the lesser-known capabilities in
Photoshop 6 is the Noise Gradient. An option when creating
or editing a gradient, it produces some truly wild
gradients! While they have their uses for complex masking
(in some limited circumstances), noise gradients are
excellent for special effects and creative accents.
Generally speaking, a noise gradient uses a
range of colors you determine, but rather than blending
between two colors, the Gradient Editor generates a series
of colors and blends them. The colors are randomly generated
within the parameters you set.
To begin the exploration of noise gradients,
open the Gradient Editor dialog box.
1. Select the Gradient tool in Photoshop's Toolbox.
2. Click once on the sample gradient in the Options Bar.
When the Gradient Editor opens, select Noise
for Gradient Type.
The Gradient Editor's options will change to
those shown here:
The first option to explore is Roughness.
Similar to the Smoothness slider for "Solid" gradients,
Roughness determines the abruptness of the transition
between colors. In the example below, there are five noise
gradients. The only difference among them is the Roughness
setting. From the top, they are 0%, 25%, 50%, 75%, and 100%.
At 300% zoom, you can see that each of the
stripes of color in the 100% Roughness sample is one pixel
wide. (It doesn't get any rougher than that, does it?) Keep
in mind that high levels of Roughness can produce
pixelization when used with non-linear gradients.
The default color model is RGB. Adjusting
the sliders determines what colors will be used to create
the gradient. Note the positions of the black and white
sliders in the following examples.
HSB (Hue/Saturation/Brightness) is an
alternative color model for noise gradient creation. In
fact, it's probably easier and more precise to use in most
cases. This is especially true if you want to create a
gradient using only tints of a particular hue. In this
sample, note how smooth the gradient is, even though
Roughness is set to 50%. That is due, in part, to the
restricted range of brightness and saturation.
You can also use HSB color model to create a
grayscale noise gradient. Simply drag the white S slider all
the way to the left. Reducing the saturation of all colors
to zero produces gray.
The third color model available is L*a*b.
This mode allows you to produce in seconds very subtle
gradients that could take a tremendous amount of work in the
Gradient Editor's Solid gradient type.
Lab mode is also great for showing that you
can move the black and white sliders past each other.
Compare the "a" component sliders in the two samples below,
and look at how it affects the gradient.
So, we've seen RGB, HSB, L*a*b, and how to
fake a grayscale. What about CMYK? To the right of the
sliders is a checkbox labeled "Restrict Colors." When this
option is selected, the Gradient Editor will rein in the
gradient, keeping all colors within the CMYK gamut.
The checkbox immediately below, "Add
Transparency," does exactly that:
The Randomize button allows the Gradient
Editor to mix and match within the color range specified.
You can click it multiple times, experimenting until you see
a gradient you like. Remember, too, that you can adjust the
sliders after clicking the Randomize button to fine-tune the
gradient.
Now that you've learned how to work with the
Gradient Editor to produce noise gradients, let's take a
look at my favorite use for them. Working with the Angle
Gradient tool, you can produce some very cool effects.
Circular noise gradients can also be useful.
You'll also find a grayscale noise gradient
to be perfect for creating those dusty beams of light
streaming through the window....