Vector objects: blend modes

The following examples show you how to apply the blending techniques discussed in Vector objects: Fill options. Bear in mind that the whole point of blending is to be able to work out what color values will be displayed when an image is composite, that is, made up of various layers and objects, with some colors overlapping one another.

Blending with vector objects is similar to blending between layers, but with these differences:

Photopaint has to calculate, for each pixel, the resultant color from a combination of the base color (the color of the layer below the vector object "layer" or the color of the object that overlaps with the selected object) and the blend color (the color of the selected vector object). The particular blend mode used determines, of course, the way the resultant color is calculated.

The default value for the blend mode is Normal, as you can see in the Mode box.

Another important concept when selecting a blend mode is that of opacity, which is set in the Opacity box. For some blend modes an effect becomes apparent only if the opacity is set at less than 100% e.g. Dissolve.

The main blend options, which you can select in the Mode box, are:

The resultant color is the same as in the currently selected object (subject to the amount of transparency set in the Opacity box, therefore visibility through to the lower layer). In effect, the base color is not used to help calculate the resultant color where the base and blend colors overlap.

An object with less than 100% opacity is converted - "dissolved" - to 100% opaque randomly scattered pixels. The effect is of a rough brushstroke, containing a mixture of blend and base pixels, rather than an evenly transparent one.

The brightness values of the base and blend colors can be combined to create a darker tone. This is done by multiplying the two brightness values when they are expressed as fractions. For example, white has a brightness value of 255 (the maximum) and is represented as 255/255 or 1; black has a brightness value of 0 (the minimum) and is represented as 0/255 or 0. All other brightness values are represented as fractions between 0 and 1 e.g. 150 is represented as 150/255; 100 as 100/255. Therefore, using Multiply we get the result (100 * 150) / (255 * 255), which works out at 59/255. You can immediately see that the resultant brightness will always be lower than (or equal to) the brightness of either one of the multiplied fractions. This intuitively fits in with our experience of placing one transparent sheet on top of another, where the result is always darker.

Note that the above means that if the blend color is white, the resultant color is the same as the base color. If the base color is white, the resultant color is the same as the blend color. If either the base or the blend color is black, the resultant color is black. If the base color is transparent, the result of blending any color is black (since a transparent layer counts as 0, that is, the same as black).

This mode has the opposite effect to Multiply, combining the base and blend colors to create a lighter tone.

These are some of the more important options, but there are many others:

Behind, Overlay, Difference, Addition, Subtraction, Darken Only, Lighten Only, Hue, Saturation, Color, Luminosity, Divide, Color Burn, Color Dodge, Hard Light, Soft Light

Remember that you can always cancel or change the effect of a blend mode by selecting another one, especially the Normal blend mode.

If you would like to make the blending operations using vector objects permanent, then you should select Flatten Image from the Layers menu. See the relevant notes in Merge operations with layers for more information.