Layers and masks explained
Layers are what separate a real image editor from a simple photo app. They let you change one part of an image without touching the rest — and change your mind later.
Layers: sheets of glass
Think of layers as sheets of glass stacked on top of each other. Each holds part of the image: a photo, some text, a shape. Where a sheet is transparent you see through to the ones below. Reordering the sheets changes what covers what.
Opacity and blend modes
A layer's opacity makes the whole sheet see-through. Blend modes change how its colours mix with what is below: Multiply darkens (great for shadows), Screen lightens, Overlay adds contrast.
Adjustment layers: changes you can undo any time
An adjustment layer doesn't contain pixels. It changes the colours of everything below it — brightness, hue, saturation, black and white — without altering the original pixels. Hide or delete it and the original is back, untouched.
Masks: hide without erasing
A mask decides which parts of a layer are visible. Paint black on the mask to hide, white to reveal, grey for something in between. Unlike the eraser, nothing is lost: paint white again and it comes back. Masks on adjustment layers let you apply an adjustment to just one area, such as brightening only a face.
Groups
Groups collect layers into folders. Moving a group moves everything in it, and a group can have its own opacity, blend mode and mask.
Try it
- Open a photo in Picstea.
- Choose Adjustments → Black & White.
- Click the adjustment layer's mask thumbnail and paint black over one object.
- That object is in colour again; everything else stays black and white.
Read more in the layers documentation.