A Quick Introduction to Blend Modes

Frankly, I never realized how much math was involved in blend modes. I don't pretend to understand the formulas but, if you are interested, make sure you check out this article, Blend Modes, by Jens Gruschel for more algebra than you can shake a PNG file at.

What follows here is my interpretation of blend modes based on some of my own research and experimentation. Some explanations of these color modes were—to me, anyway—only comprehensible to a scientist. In situations like that, I do my best to explain what I believe is happening.

For a blend mode to do anything, there must be at least two objects or layers containing pixel data. The result of a blend mode is based on how color pixels from each object react to the mode chosen.

A blend mode contains the following elements:

• Opacity: Degree of transparency to which the blend mode is applied
• Blend color: Color you add with your paint tool or that is already on the layer which will have the blend mode applied
• Base color: Color of pixels underneath the blend color
• Result color: What you get after "blending"

Blend modes affect how the colors of one layer or object blend with the colors of a layer or object directly below it. If you apply a blend mode from the Layers panel, it affects the entire layer or object; it is not affected by bitmap selections.

Each object and each layer can have its own blend mode. Talk about permutations! Blend modes can also be applied to vector tools such as shapes, text, pen, and line tools. You can set the blend mode before you draw or afterwards. Blend modes applied to vector images are always editable, even if the vector is filled with a bitmap texture or pattern.

Another great feature of blend modes is that you can apply them with the bitmap paint tools (paint brush, pencil, and paint bucket). Select the tool, choose a fill color, choose a blend mode from the Properties inspector, and then paint. This gives you very detailed control over the effect of a blend mode but, unlike object and layer application, this method is also destructive; it changes pixels permanently. I think this feature may be very useful to those with drawing tablets. It's even fun using the mouse (see Figure 1).

Figure 1. Collage of two images using a vector mask and the subtractive blend mode on the image in the horizon. I added a zoom blur to this image and then applied multiple paint brush strokes at varying sizes with different blend setting (see source file beach_blend.png).

You can also combine blend modes, the paint brush, and bitmap selectios to enhance a particular area of your image (see Figure 2). I used the Magic Wand tool to select the yellow leaf. Then using the Paint Brush tool, I selected the Freeze Blend mode and a paint color of #FF6600 to give the leaf some surreal snap (see Figure 3).

I like to categorize the blending modes in Fireworks as follows:

• Opacity modes: Normal and Average
• Darkening modes: Darken, Multiply, Color Burn, Inverse Color Burn, and Soft Burn
• Lighten modes: Lighten, Screen, Color Dodge, Inverse Color Dodge, and Soft Dodge
• Lighting Effects modes: Overlay, Soft Light, Fuzzy Light, and Hard Light
• Invert modes: Difference, Exclusion, and Negation
• Color modes: Hue, Saturation, Color, Luminosity, Red, Green, and Blue
• Thermal modes: Reflect, Glow, Heat, and Freeze (OK, so "thermal modes" is my idea but with mode names like heat, I couldn't help myself)
• Math modes: Additive, Subtractive, Subtract, Interpolation, Stamp, and XOR Invert and Tint are grouped together, but I think they'd be happier in the Invert and Color families

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