Luminosity painting is a convenient and controllable method to adjust brightness and contrast by painting on a layer in Photoshop. As its name implies, it uses the luminosity masks discussed in the Luminosity Masks tutorial to achieve its end result. The painting occurs on a pixel-containing layer, which is a relatively straightforward process in Photoshop. The pixel-containing layer is called a Burn/Dodge layer. It’s created in the following manner:
1. Create a new, empty layer as the topmost layer in the layer stack (Shift-Opt-Cmd+N).
2. Change the blending mode at the top of the Layers palette to Soft Light.
3. Fill the layer with 50% gray (Edit > Fill > Use: 50% Gray, Mode: Normal, Opacity: 100%).
4. Rename the layer “Burn/Dodge.”
Soft Light mode darkens or lightens the color below it in proportion to how much darker or lighter the color is than 50% gray. The fill color of 50% gray is totally neutral. It neither lightens nor darkens the colors below it, so when the layer is filled with 50% gray, it has no effect on how the image looks. Painting black or white on this layer, however, will have an effect. White is lighter than 50% gray, so anything beneath the white paint will be lightened. In the darkroom, this procedure is called “dodging.” Painting black on the Burn/Dodge layer causes all colors below the paint to darken. This is called “burning.” So simply painting white and black on the Burn/Dodge layer allows brightness or darkness to be painted into specific areas of the image.
When burning and dodging by painting on a Burn/Dodge layer, a feathered brush is generally used with the brush size scaled appropriately for the area being painted. The brush’s opacity is usually set to less than 10%. Even small amounts of paint applied to the Burn/Dodge layer can produce significant changes, so using a low-opacity brush insures that it’s not carried too far too fast. It’s ideal to make several passes with the brush to slowly build up the effect. If burning or dodging does go too far, simply use the opposite color to paint over the area. This moves the color back toward 50% grays and reverses the effect.
Luminosity painting is a specialized form of burning and dodging. While it utilizes the Burn/Dodge layer, it does so by painting black and white through an active luminosity mask selection. The selection controls how much paint is deposited on each pixel, and, because the selection is based on an image’s tonal values, painting trough a luminosity selection confines the paint to specific tones in the image. In this way, not only is image brightness controllable with luminosity painting, so is contrast. The contrast control is particularly exciting. Properly used, luminosity painting creates a contrast brush. It’s possible to use it to add or remove contrast simply by painting on the Burn/Dodge layer. While adjustment layers are probably the best way to change global brightness and contrast, luminosity painting is an excellent method for managing it in specific areas of an image.
- Create a Burn/Dodge layer.
- Create the desired luminosity mask selection. The Luminosity Masks tutorial explains how to do this. It’s often useful to make selections of several similar masks and save them on the Channels palette in order to experiment with which works best.
- Type Cmd+H to hide the marching ants that define the selection. Hiding the marching ants makes it easier to see what’s happening as painting occurs on the Burn/Dodge layer. It’s important to understand that after typing Cmd+H the selection is still active and is controlling how much paint gets applied to each pixel.
- Paint the appropriate color (black to burn, white to dodge) onto the Burn/Dodge layer until the desired level of brightness and contrast is achieved. The opacity of the brush may need to be set considerably higher than what is needed for regular burning and dodging. All luminosity selections will block the paint from being deposited on the Burn/Dodge layer to some degree. Higher opacity settings for the brush are often needed to force enough paint through the selection to have the desired effect. A stroke or two of the brush will provide quick visual feedback for adjusting the brush’s opacity. Don’t forget that it’s best to build the effect gradually with multiple strokes instead of trying to paint in the effect in just one pass and be sure to use a feathered brush.
- Deselect (Cmd+D). The absence of the marching ants can make it easy to forget that there is an active selection. After painting, deselecting turns off the hidden selection so that it won’t influence subsequent steps in the workflow of the image
Which mask and whether to dodge or burn? To answer this ask two questions. Start with “Does the area need to be lightened or darkened?” This determines which color to choose for painting. Choose white to lighten and black to darken. The second question to ask is “Does the area need more contrast or less contrast?” If it needs more contrast, choose a luminosity selection to paint through that reveals tones of the painting color, e.g. one of the “Lights” selections if painting with white. This is what was done in the example of opening up the shadows (white paint through the Lights selection increased contrast). If less contrast is need, choose a selection to paint through that conceals tones of the painting color, e.g. one of the “Lights” selections if painting with black. This is what was done in the example of darkening the highlights (black paint through the Bright Lights selection decreased contrast). The table below summarizes the different combinations, but after working it out a couple of times with actual images, the right combo is quickly obvious.
|If you want …||And…||Paint…||Through a…|
|Increase brightness||Increase contrast||White||“Lights” selection|
|Increase brightness||Decrease contrast||White||“Darks” selection|
|Decrease brightness||Increase contrast||Black||“Darks” selection|
|Decrease brightness||Decrease contrast||Black||“Lights” selection|
Experiment with Luminosity paint on several different images. Post Labeled before/after images on your digital portfolio under TE.