Overlay mode

One of the most useful blend modes in Photoshop and other image editors. When it’s applied to an image layer or adjustment layer it changes the appearance of the layer below. Tones darker than 50% make the those areas in the layer below look darker, tones lighter than 50% make them appear lighter. It’s often used for dodging and burning effects or for increasing contrast.

Layers

Best thought of as a series of transparent overlays you can place over an image to add other images, text, effects or adjustments. You can also use masks to hide or show different parts of each layer and control the areas they affect.

Color Burn

A layer blend mode found in most programs that support image layers. Using this mode produces an ultra-high contrast composite image based on the layer it’s applied to and the layer(s) underneath.

Blend mode

The way the pixels from one layer in a montage interact with those in the layer below. In ‘Normal’ blend mode, the pixels on the top layer completely cover the ones below, in ‘Multiply’ mode their values combine to produce images that are darker overall, in ‘Overlay’ mode, pixels lighter than 50% grey lighten those in the layer below while pixels darker than 50% grey darken them… there are many other blend modes besides these.

Adjustment layer

A special type of layer in image-editing software which is designed to hold adjustments rather than other image layers. It’s a way of ‘stacking’ a series of adjustments to an image without affecting the image layer itself.