Want to win some bets at Photoshop World?
Ask your buddy to name all of Photoshop's blending modes.
Odds are, he or she won't know all 21 of them. That's right,
21 (twenty-one) blending modes! (Of course, if he or she
visits Planet Photoshop, don't offer the wager.)
Be careful how you phrase this challenge.
Don't qualify the bet by saying "layer blending modes." A
lot of knowledgeable Photoshop users can come up with all 17
standard blending modes. Many of them will even remember the
18th blending mode, Behind, found with the painting tools.
If he or she has really been paying
attention, the blending mode Clear might be listed. It's
found with the Paint Bucket, the shape tools (in Create
Filled Region mode), the Photoshop 5 Line tool, and the Fill
command.
All right, well, that's 19 blending modes.
What about numbers 20 and 21? You'll have to look hard for
them. The menu commands Image> Apply Image and Image>
Calculations are the secret. Buried deep within their dialog
boxes are the blending modes Add and Subtract.
The blending modes Add and Subtract are
found only with the Apply Image and Calculations commands.
So now that we know how many there are, what are blending
modes? In a nutshell, blending modes are used to determine
the interaction of two color values for a single pixel.
• Two layers may have different colors for
the same location (pixel) in an image.
• A painting tool may add a color to a pixel that already
has an assigned color value.
• Multiple color channels may be used to produce a single
color value.
When talking about blending modes, we normally use three
terms:
• The base color is the original color of a specific pixel.
• The blend color is the color being applied.
• The result color is the end product of the interaction
between the base and blend colors. Changing the blending
mode can have a substantial impact on the result color.
For a quick look at what blending modes do,
lets see some examples. In the following image, the text
layer has a blending mode of Normal. The pixels on the top
(type) layer do not interact with the pixels below, they
simply block them (depending upon opacity settings).
In this image, the only change that has been
made is a switch of blending modes for the type layer. It is
now set to Screen.
Changing to the Exclusion blending mode
creates a much different look.
Notice how in the Screen and Exclusion
blending modes the text's areas of solid color change
according to the color beneath. In these examples, the
colors found in the image of the bear are the base colors,
the color values of the text (with bevel and drop shadow)
are the blend colors, and the colors you see when the two
are mixed are the result colors.
Because the change is being made to a
layer's blending mode, everything on the layer is affected.
In the case of the type layer, the layer effects (bevel and
drop shadow) are affected.
Keep in mind that layer blending work
downward – the blend color must always be above the base
color to create a result color. And remember that the
reversing layers and blending modes can change the result
color. In this image, the bear layer has been moved above
the type layer. The type layer's blending mode has been
returned to Normal, and the bear layer's mode is Exclusion.
Note the difference between this image and the previous
image.
In the next column, we'll start describing
the individual blending modes and how each works.