Working with Tools in Paint Shop Pro 8 - Blend Mode
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Blend mode is one of the more complex options in Paint Shop Pro. The blend mode you set determines how the color on your tool blends with a color in your image. The result of this blending of tool color and target color is determined on a pixel-by-pixel basis, depending on the blend mode you select. You can also select a blend mode for a layer, and that blend mode determines how the colors on that layer blend with the colors on the layers below.
There are several blend modes, all of which are available both for the various painting tools as well as for multiple layers in an image. You start with a blend color—the coloron your painting tool/upper layer. This blend color mixes with the base color—a color already on the current layer/lower layer. The result color you get depends on the blend mode you select.
Each of the images shown here contains two layers: The bottom layer contains a gradient that changes gradually from a very dark red to white. On the upper layer, where I'll change the blend modes, there are three stripes. The upper-left stripe is a fully saturated yet very pale yellow {HSL: 44/255/220}. The middle stripe is a medium light, medium saturated blue {HSL: 168/120/128}. The lower-right stripe is a dark, lightly saturated green {HSL: 71/85/57}. Both layers are set at 100% opacity. So you have a better idea of the result of using a particular blend mode, be sure to look for these same figures in the Color Gallery in this book.
With a Normal blend mode, the blend color replaces the base color. It's then up to the Opacity setting to determine to what extent that replacement is made: totally (Opacity = 100) or partially (Opacity < 100). With Opacity set to less than 100, a percentage of the base color, equal to 100 minus the Opacity setting, is mixed with the blend color.
Figure 3.2 Normal blend mode.
With the Darken blend mode, the blend color is blended with the base color to produce a result, and this result replaces the base color only if it is darker than the base. If you're using a tool to apply the blend color, the color will appear only when the result is darker than the existing color. If you're using Darken mode with layers, the colors on the top layer replace those on lower layers only if the result is darker. If the base color is replaced, the Opacity setting determines by how much. Notice that the result of blending a very light yellow with the background gradient doesn't produce a darker result, so that stripe disappears. The medium stripe gets darker as a result of the Darken blend mode, while the already dark green stripe remains unchanged.
Figure 3.3 Darken blend mode.
Lighten blend mode, predictably, works the opposite way of Darken: The result color replaces the base color only when the result color is lighter than the base color. If you use the Lighten blend mode with layers, the colors on the top layer replace those on lower layers only if they are lighter. Again, use the Opacity setting to control the amount of replacement. With Lighten mode, the dark green stripe disappears; the medium blue stripe disappears when it's blended with the light colors of the base color gradient in the upper-right corner but shows through slightly in the darkest portion of the gradient in the lower-left corner. The light yellow stripe appears unchanged.
Figure 3.4 Lighten blend mode.
With the Hue blend mode, only the blend color's hue value (the H in the HSL color model) is applied to the base color. As a result, the base color retains its original saturation and luminosity values, but it changes hue. Remember, in the HSL color model, there are only 256 possible hues, and all possible color values are variations of those 256. When Opacity is set to less than 100, (100 – Opacity)% of the base color's original hue remains after the blend. With this mode, you can clearly see the colors used in each of the three stripes on the upper layer, but they are shaded from dark to light because of the underlying gradient's change in luminosity.
Figure 3.5 Hue blend mode.
PSP 8 also includes several legacy blend modes such as Hue (Legacy) and Color (Legacy). These modes do not work as described here; instead, they re-create the way in which that particular blend mode worked in PSP 7 (which was not how the Help system described them).
This chapter is from Paint Shop Pro 8, by Jennifer Fulton, (Sams, 2004, ISBN: 0672323893). Check it out at your favorite bookstore today.
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