Coloring effects

Retouching with overlays

Let’s look at more ways these and other overlay blending modes can be applied when retouching a photograph. Suppose you have a landscape picture and are looking for a simple method to remove the clouds from the sky. Cloning with the clone stamp tool or cutting and pasting feathered selections could possibly work, but you would have to be very careful to prevent your repairs from showing. For example, how will you manage to clone in the sky around the branches and leaves?

The sky is graduated from dark blue at the top to a lighter blue on the horizon. The easiest way to approach this task is to fill the sky using a gradient set to the Darken blending mode. The foreground and background colors used in the gradient are sampled from the sky image. Darken mode checks the pixel densities in each color channel. If the pixel value is lighter than the blend color it gets replaced with the blend color. In the accompanying example, the clouds (which are lighter than the fill colors) are removed by a linear gradient fill. The trees, which are darker than the fill colors, are left almost completely unaltered. To apply a gradient fill, I clicked the fill layer button at the bottom of the Layers palette and chose Gradient. The Gradient type was Foreground to Background, and I changed the fill layer blending mode to Darken. Before I did this, I loaded the blue channel as a selection. The Blue channel contains the most contrast between the sky and the trees. When a selection is active and you add a new fill or adjustment layer, or you click on the Add layer mask button, a layer mask is automatically added which reveals the selected areas only. As with adjustment layers, fill layers can be adjusted on-the-fly while retaining the layer masking.

Color mode: The hue and saturation values of the blend layer are combined with the luminosity of the underlying layers. The effect is to colorize the layers below.

Hue mode: Only the hue values of the blend layer are combined with the underlying saturation and luminosity values. The layers beneath are colorized, but the saturation of the base image is retained.

Saturation mode: The saturation values of the blend layer replace those of the underlying layer. A pastel colored overlay layer will cause the underlying layers to become desaturated, but not alter the hue or luminosity values.

Luminosity mode: The brightness values of the blend layer replace those of the underlying, but do not effect the hue and saturation.

Adobe Photoshop 7.0 for Photographers

1The before picture contains a cloudy sky. Sample colors from the top of the sky and from the horizon to set the foreground and background colors.

2 Load the blue channel as a selection and click on the Create new fill button at the bottom of the Layers palette to add a new gradient fill layer. The Gradient Fill dialog opens. Click OK to add a new layer using the Foreground to Background gradient at the angle shown.Then set the fill layer to Darken blending mode.The pre-loaded selection will have added a layer mask to hide the tree branch outlines.