Using Blend Modes in Photoshop-- Part II

Article and Photography by Ron Bigelow

www.ronbigelow.com

Photoshop CS or Photoshop CS2 Used in this Tutorial

Linear Burn Blend Mode

The Linear Burn Blend mode is similar to the Color Burn Blend mode. In each channel, the Linear Burn Blend mode analyzes the colors and does two things to create the result color:

Darkens the base color in relation to the tonality of the blend color. The darker the blend color, the darker the base color becomes to create the result color.
Adds the blend color to the base color in relation to the tonality of the blend color. The darker the blend color, the greater the amount of the blend color that is added to the base color to create the result color.

The main difference between the Linear Burn Blend mode and the Color Burn Blend mode is that the Color Burn Blend mode increases the contrast of the base color, as the blend color gets darker, while the Linear Burn Blend mode does not increase the contrast.

If the blend color is white, the Linear Burn Blend mode does nothing. As the blend color gets darker, the effect of the Linear Burn Blend mode becomes more intense.

Again, there are other ways to add density and color to an image. The advantage of the Linear Burn Blend mode is that it allows for a greater effect in the darker parts of the image when so desired.

Figures 1 and 2 demonstrate the use of the Linear Burn Blend mode. It was desired to darken the leaves and increase the amount of red in the leaves. This was done by duplicating the Background layer, setting it to the Linear Burn Blend mode, and adjusting the Opacity. A mask was used to restrict the Linear Burn effects to the leaves while leaving the background unaffected by the changes. Figure 1 shows the image before the Linear Burn step, Figure 2 shows it afterwards. Figure 3 shows the Layers Palette with the Background Copy layer set to the Linear Burn Blend mode.

Figure 1: Image before Adjustment

Figure 2: Leaves Adjusted with Linear Burn Blend mode

Figure 3: Layers Palette with Linear Burn Blend Mode on Background Copy Layer

Table 1 summarizes the Linear Burn Blend mode.

Table 1: Linear Burn Blend Mode
What it does	To create the result color, in each channel, the base layer becomes darker and picks up more of the blend color as the blend color becomes darker.
Uses	Used for making tonal and color adjustments that are dependent on the tonality of the blend color.

Lighten Blend Mode

This is the opposite of the Darken Blend mode. The Lighten Blend mode creates the result color by comparing the base color to the blend color, in each channel, and selecting the lighter of the two. As a consequence, in each channel, base colors darker than the blend color are changed to the blend color; base colors lighter than the blend color are unaffected. Mathematically, the Lighten Blend mode is defined as:

In Each Channel, Result Color = Base Color if Base Color is Lighter than Blend Color
or Blend Color if Base Color is darker than Blend Color.

As with the Darken Blend mode, a primary use of the Lighten Blend mode is to combine masks. However, in the case of the Lighten Blend mode, the masks reveal effects (unless you invert them). This is done by using the Lighten Blend mode with the Calculations command.

Figure 4 shows an image where the Lighten Blend mode and the Calculations command where used to combine masks.

Figure 4: Image Requiring the Combining of Masks

In this image, it was necessary to sharpen the hills and the moon. The sand dunes were not to be sharpened. One mask had already been made for the mountains. The channel for that mask is shown in Figure 5.

Figure 5: Mountains Mask Channel

Figure 6: Moon Mask Channel

A mask for the moon had also already been created. The channel for that mask is shown in Figure 6. These two channels were combined to create a new channel. This new channel was used to generate a mask for the sharpening layer.

Figure 7: Calculations Palette

Figure 7 shows the Calculations palette (click Image/Calculations) with the Blend set to Lighten. The new mask generated by the Calculations command can be seen in Figure 8.

Figure 8: New Mask Generated from Calculations

Table 2 summarizes the Lighten Blend mode.

Table 2: Lighten Blend Mode
What it does	Creates the result color by comparing the base color to the blend color, in each channel, and selecting the lighter of the two.
Formula	In Each Channel, Result Color = Base Color if Base Color is Lighter than Blend Color or Blend Color if Base Color is darker than Blend Color.
Uses	Used for combining masks

Screen Blend Mode

The Screen Blend mode is basically the opposite of the Multiply Blend mode. In each channel, the Screen Blend mode multiplies the inverse of the base and blend colors to create the result color. As a result, every pixel will get lighter (unless one of the colors is black). Any color (base or blend) multiplied by white produces white, and any color (base or blend) multiplied by black remains unchanged. In essence, the Screen mode thins out the image density. Mathematically, the Screen Blend mode is defined as:

In Each Channel, Result Color = 255 - [(255 - Base Color)*(255 - Blend Color)/255]

The part of the formula in brackets is divided by 255 so that the result color will fit in the 0 -- 255 range of values, for each of the three colors, used in the RGB color spaces.

The Screen Blend mode is often used to lighten areas that are too dark. Often, this is done by duplicating the Background layer and setting the Blend mode of the Background Copy layer to Screen. This technique is demonstrated in Figures 9 and 10. Figure 9 shows an image with dark shadows that lack detail. In Figure 10, the Background layer was duplicated twice and the Background copies set to Screen Blend mode with a mask used to protect the sky and sunlit mountains. This improved the detail in the shadows. Figure 11 shows the Layers Palette with the duplicated Background layers set to the Screen Blend mode.

Figure 9: Image before Adjustment

Figure 10: Shadows Adjusted with Screen Blend Mode

Figure 11: Layers Palette with Screen Blend Mode on Background Copy Layers

Table 3 summarizes the Screen Blend mode.

Table 3: Screen Blend Mode
What it does	In each channel, multiplies the inverse of the base and blend colors to create the result color.
Formula	In Each Channel, Result Color = 255 - [(255 - Base Color)*(255 - Blend Color)/255]
Uses	Used for building up detail and density in dark areas.

Color Dodge Blend Mode

The Color Dodge Blend mode is basically the opposite of the Color Burn Blend mode. In each channel, the Color Dodge Blend mode analyzes the colors and does three things to create the result color:

Lightens the base color in relation to the tonality of the blend color. The lighter the blend color, the lighter the base layer becomes to create the result color.
Decreases the contrast of the base color in relation to the tonality of the blend color. The lighter the blend color, the less the contrast of the base layer becomes to create the result color.
Adds the blend color to the base color in relation to the tonality of the blend color. The lighter the blend color, the greater the amount of the blend color that is added to the base color to create the result color.

In short, as the Blend mode color becomes lighter, the base layer becomes lighter, less contrasty, and picks up more of the blend color to create the result color. If the blend color is black, the Color Dodge Blend mode does nothing. As the blend color gets lighter, the effect of the Color Dodge Blend mode becomes more intense.

The advantage of the Color Dodge Blend mode is that it is dependent on the tonality of the blend color. This is an advantage for images where it is desired to have a greater effect in the lighter parts of the image.

Figures 12 and 13 demonstrate the use of the Color Dodge Blend mode. This image was particularly challenging to edit. This scene was shot from a desert plateau overlooking the desert valley below as a major storm was just breaking up. The sun was setting and had just broken thought the clouds to create a dramatically lit scene with the clouds seeming to glow from within from the light. The mountain ridges were in silhouette and contrasted in tone with the dramatically lit clouds. The problem was that the clouds came out lackluster in the image. They seemed somewhat dull and did not dramatically separate from the dark mountain ridges as well as they should have. Various attempts at curves, levels, dodging, and other methods never produced the desired effect. An additional problem with these approaches was that they all required masks to protect the dark mountain ridges from the affects of the editing. These masks required a lot of finessing to produce a mask that was not obvious at the places where the white clouds touched the dark mountains. The Color Dodge Blend mode solved the problem. The Background layer was duplicated and set to Color Dodge Blend mode. This lightened the clouds but left the dark ridges unaffected. Thus, the clouds picked up the feeling of diffused light and separated much better from the mountains. Furthermore, since the Color Dodge Blend mode did not affect the dark areas, the desired affect blended seamlessly from the light clouds to the dark mountains with no mask required. Figure 12 shows the image before the Color Dodge step, Figure 13 shows it afterwards. Figure 14 shows the Layers Palette with the Background Copy layer set to the Color Dodge Blend mode.

Figure 12: Image before Adjustment

Figure 13: Image Adjusted with Color Dodge Blend Mode

Figure 14: Layers Palette with Color Dodge Blend mode on Background Copy Layer

Table 4 summarizes the Color Dodge Blend mode.

Table 4: Color Dodge Blend Mode
What it does	To create the result color, in each channel, the base layer becomes lighter, less contrasty, and picks up more of the blend color as the blend color becomes lighter.
Uses	Used for making tonal and color adjustments that are dependent on the tonality of the blend color.

Linear Dodge Blend Mode

The Linear Dodge Blend mode is similar to the Color Dodge Blend mode. In each channel, the Linear Dodge Blend mode analyzes the colors and does two things to create the result color:

Lightens the base color in relation to the tonality of the blend color. The lighter the blend color, the lighter the base layer becomes to create the result color.
Adds the blend color to the base color in relation to the tonality of the blend color. The lighter the blend color, the greater the amount of the blend color that is added to the base color to create the result color.

The main difference between the Linear Dodge Blend mode and the Color Dodge Blend mode is that the Color Dodge Blend mode decreases the contrast of the base color, as the blend color gets lighter, while the Linear Dodge Blend mode does not decrease the contrast.

If the blend color is black, the Linear Dodge Blend mode does nothing. As the blend color gets lighter, the effect of the Linear Dodge Blend mode becomes more intense.

The advantage of the Linear Dodge Blend mode is that it allows for a greater effect in the lighter parts of the image when so desired.

Figures 15 and 16 demonstrate the use of the Linear Dodge Blend mode. Again, it was desired to lighten the clouds. To start off the image editing, a curve was added to the image to add some overall contrast. However, the clouds were still too dark. Another curve could have been used to deal with the clouds, but it would have required a fair amount of finessing to lighten the clouds without affecting the dark trees. Duplicating the Background layer and setting the Blend mode to Linear Dodge quickly and easily solved the problem. Figure 15 shows the image before the Linear Dodge step, Figure 16 shows it afterwards. Figure 17 shows the Layers Palette with the Background Copy layer set to the Linear Dodge Blend mode.

Figure 15: Image before Adjustment

Figure 16: Image Adjusted with Linear Dodge Blend Mode

Figure 17: Layers Palette with Linear Dodge Blend Mode on Background Copy Layer

Table 5 summarizes the Linear Dodge Blend mode.

Table 5: Linear Dodge Blend Mode
What it does	To create the result color, in each channel, the base layer becomes lighter and picks up more of the blend color as the blend color becomes lighter.
Uses	Used for making tonal and color adjustments that are dependent on the tonality of the blend color.

Overlay Blend Mode

The Overlay Blend mode is a combination of the Multiply and Screen Blend modes. The Overlay Blend mode multiplies the dark areas and screens the light areas. However, areas where the blend color has a tonality of 50% gray are not affected by the Overlay Blend mode. The result color is a blend of the base and blend colors. The shadows and highlights of the base layer are preserved.

One of the major uses of the Overlay Blend mode is with High Pass sharpening. The sharpening layer is changed to Overlay Blend mode before the High Pass filter is run. The Overlay Blend mode can also be used for tonal and color adjustments. Another interesting use for the Overlay Blend mode is for producing glows in images. This produces surrealistic, dreamlike images. For this effect, the image is duplicated into a new layer. The new layer is blurred with the Gaussian Blur filter and set at the top of the layers. The Duplicated layer is then set to Overlay Blend mode and the Opacity adjusted to produce the desired effect.

Figures 18 and 19 demonstrate the use of the Overlay Blend mode to produce a glow effect. For this image, the image was duplicated into a new layer. This was performed twice. Each of the new layers was blurred (the layers were renamed Blur 1 and Blur 2). The blurred layers were then set to the Overlay Blend mode. Both of these blurred layers were necessary to produce the desired glow effect on this image. Figure 18 shows the image before the glow effect was created. Figure 19 shows it afterwards. Figure 20 shows the Layers Palette with the Background Copy layers set to the Overlay Blend mode.

Figure 18: Image before Adjustment

Figure 19: Image after Blur Effect with Overlay Blend Mode