Layer Blending
 

Layers by default sit on top of each other hiding what lies below. There are various options that effect the way the layer below interacts. These are in the drop down on the layer palette.

Some are more useful than others and I'll only go through the common options

In the example I've duplicated the background and created a layer mask so that only the sky will be affected

Remember that in all cases you can adjust the opacity of the top layer to reduce the effect

  
 

Normal

The default, one layer sits atop the other and hides everything below it

As there is no transparency the image will stay the same

If part of the image are partially transparent multiple layers will cause the transparency to decrease.

  
 

Blends that darken

  
 

 
Original

Multiply

This darkens the colours towards black, multiplying with black produces black, multiplying with white produces no change.
 

 

Colour Burn

Darkens each colour channel by increasing the contrast.

Linear Burn

Darkens each colour channel by decreasing the brightness
 

Darken

Pixels from the darker layer will show. This has no effect when blended with itself.

  
 

Blends that lighten

    
 
Original

Screen
Imaging projecting both images from a slide onto a screen. This is very useful for blending one image into another

Colour dodge
Brightens each colour channel colours by decreasing contrast

Linear dodge
Brightens each colour channel by increasing brightness
 
 

Lighten

Only where the top image is lighter will the pixels be visible

  
 

Other blends

  
 

Hue

Uses the colour (hue) from the top layer but the brightness and saturation from the bottom layer

Filling the layer with black will produce a grayscale image or colour a tinted image

  
 

Colour

Uses the hue and saturation from the top layer but the brightness from the bottom layer.

Filling the layer with a colour will create a tinted version of an image. This is a flatter image than using the hue blend.

 
 

Saturation (not so useful)

Use the saturation from the top layer and the colour (hue) but the brightness from the bottom layer

This is not a useful example - you might use it ona partially washed out image.

  • Add a layer,
  • Fill with with a strongly saturated colour
  • Add a black mask
  • Paint the mask white/grey where you want to increase the saturatation