Adjustment layers let you experiment with color and make tonal adjustments without permanently modifying the pixels in an image. You can think of an adjustment layer as a veil coloring the underlying layers. By default, an adjustment layer affects all layers below it, although you can change this behavior. When you create an adjustment layer, the Layers panel displays a white box representing the adjustment for that layer.
Fill layers let you fill a layer with a solid color, gradient, or pattern. Unlike adjustment layers, fill layers do not affect the layers below them. To paint on a fill layer, you must first convert it (simplify it) into a regular layer.
Adjustment and fill layers have the same opacity and blending mode options as image layers, and you can move and reposition them just as you do image layers. By default, adjustment and fill layers are named for their type (for example, Solid Color fill layer and Invert adjustment layer).
A. Fill layers B. Adjustment layers
To affect all the layers below the adjustment layer, click the Create New Fill or Adjustment Layer button in the Layers panel. Then, choose one of the following adjustment types. (The first three options in the menu are fill layers, not adjustment layers.)
Corrects tonal values in the image.
Lightens or darkens the image.
Adjusts colors in the image.
Maps pixels to the color in the selected gradient.
Adjusts the color balance and color temperature of the image.
Produces a photo negative effect by creating a negative based on the brightness values of the image.
Renders the image in monochrome with no gray, so that you can locate the lightest and darkest areas.
Gives a flat, poster-like appearance to a photo by reducing the number of brightness values (levels) in the image, thus reducing the number of colors.
Selecting Use Previous Layer to Create Clipping Mask in step 3, groups the adjustment layer with the layer immediately below it and the effect is confined to the group.
Applying a correction using the Smart Brush tool or the Detail Smart Brush tool automatically creates an adjustment layer.
Click the Create New Fill or Adjustment Layer button in the Layers panel, and choose the fill type you want to create. (The first three options listed in the panel are fill layers, the others are adjustment layers.)
Choose Layer > New Fill Layer > [fill type]. In the New Layer dialog box, click OK.
Creates a layer filled with a solid color chosen from the Color Picker.
Creates a layer filled with a gradient. You can choose a predefined gradient from the Gradient menu. To edit the gradient in the Gradient Editor, click the color gradient. You can drag within the image window to move the center of the gradient.
You can also specify the shape of the gradient (Style) and the angle at which it is applied (Angle). Select Reverse to flip its orientation, Dither to reduce banding, and Align With Layer to use the layer’s bounding box to calculate the gradient fill.
Creates a layer filled with a pattern. Click the pattern, and choose a pattern from the pop‑up panel. You can scale the pattern and choose Snap To Origin to position the origin of the pattern with that of the document window. To specify that the pattern moves with the Fill layer as it is relocated, select Link With Layer. When this option is selected, you can drag within the image to position the pattern while the Pattern Fill dialog box is open. To create a new preset pattern after editing pattern settings, click the New Preset button.
Double-click the adjustment or fill layer’s leftmost thumbnail in the Layers panel.
Select the layer in the panel and choose Layer > Layer Content Options.
You can merge an adjustment or fill layer in several ways: with the layer below it, with other selected layers, with the layers in its own group, with the layers it’s linked to, and with all other visible layers. You cannot, however, use an adjustment layer or fill layer as the base or target layer for a merge.
When you merge an adjustment layer or fill layer with the layer below it, the adjustments are simplified and permanently applied to the merged layer. The adjustment no longer affects other layers below the merged adjustment layer. You can also convert (simplify) a fill layer into an image layer without merging it.
Adjustment layers and fill layers with masks (the layer’s rightmost thumbnail in the Layers panel) that contain only white values do not add significantly to the file size, so you don’t need to merge these adjustment layers to conserve file space.
A layer mask prevents sections of a layer, or an entire layer, from being visible. You use the mask to show or hide sections of an image or an effect. When the layer mask (right thumbnail) attached to an adjustment layer is completely white, the adjustment effect is applied to all underlying layers. If you don’t want to apply the effect to certain portions of the underlying layers, paint the corresponding area of the mask with black. When attached to a fill layer, the mask defines the filled‑in area in the fill layer.
To view only the mask, Alt-click (Option-click in Mac OS) the layer mask’s thumbnail (the rightmost thumbnail). Alt-click (Option-click in Mac OS) the thumbnail again to redisplay the other layers.
To view the mask in a red masking color, hold down Alt+Shift (Option+Shift in Mac OS) and click the layer mask’s thumbnail (the rightmost thumbnail). Hold down Alt+Shift (Option+Shift in Mac OS) and click the thumbnail again to turn off the red display.
To constrain editing to part of the mask, select the corresponding pixels.
To remove areas of the adjustment effect or fill, paint the layer mask with black.
To add areas to the adjustment effect or fill, paint the layer mask with white.
To partially remove the adjustment effect or fill so that it shows in various levels of transparency, paint the layer mask with gray. (Single-click the foreground color swatch in the toolbox to choose a gray shade from the Swatches panel.) The extent to which the effect or fill is removed depends on the tones of gray you use to paint. Darker shades result in more transparency; lighter shades in more opacity.
Shift-click the mask thumbnail (the layer’s rightmost thumbnail) in the Layers panel to turn off the mask; click the thumbnail again to turn on the mask.