You can't directly resize an adjustment layer in Photoshop in the same way you resize a regular layer containing pixels. Adjustment layers affect the pixels beneath them; they don't have pixel dimensions themselves that can be scaled. Instead, you modify the effect of the adjustment layer by adjusting its properties.
Understanding Adjustment Layers
Adjustment layers modify the appearance of the layers below without altering the original pixel data. They operate by applying various non-destructive edits like brightness/contrast, color balance, and more. Their impact is determined by their settings, not their size. Adobe Help on Adjustment Layers
Modifying the Adjustment Layer's Effect
To change how an adjustment layer affects the image:
- Select the adjustment layer: Locate the adjustment layer in the Layers panel.
- Double-click the layer thumbnail: This opens the adjustment layer's properties dialog box.
- Adjust the settings: Modify the sliders or parameters within the dialog box to achieve the desired effect. For example, adjust the contrast or saturation settings within the Levels or Hue/Saturation adjustments.
Resizing the Area of Influence (Clipping Masks)
If you want to limit an adjustment layer's effect to a specific area, use a clipping mask.
- Select the adjustment layer.
- Select the layer you want the adjustment to affect.
- Right-click: Choose "Create Clipping Mask" (or use the keyboard shortcut: Option+Command+G on Mac or Alt+Ctrl+G on Windows)
Using Transform for Gradient Fill Layers (Common Misunderstanding)
Some users might confuse gradient fill layers with adjustment layers. Gradient fill layers can be resized using the Free Transform tool (Ctrl+T on Windows or Command+T on Mac). However, this is different from resizing an adjustment layer itself, which isn't possible. StackExchange Discussion on Scaling Layers
In short: You modify the area of influence of an adjustment layer (through clipping masks) or the strength of its effect (through property adjustments), not its size itself. The Free Transform tool (Ctrl+T / Command+T) only works with pixel-based layers, not adjustment layers.
