Digital Darkroom: Seamless composites in four easy steps

This is the first in an occasional series in which I share processing tips and tricks.

If you've got two or more photos of a bird against a plain background (usually a blue sky), there's a quick and easy way to turn them into a composite image like this one:

Bittern (composite), Grove Ferry, January 2012

As well as being fast, this method also avoids the unsightly halos often seen in composite photos where the sky colours don't quite match. The steps below apply to Photoshop, but most photo-editing programs will have similar functions.

1) Open one of the images you want to cut from, select the Magic Wand Tool (W) and click anywhere on the background sky. The "marching ants" outline will show you what's been selected.

2) From the menu, choose Select > Inverse. Now only the bird should be selected. If you find that other areas (like bright clouds) are still selected, switch to the Lasso Tool (L), click on "Subtract from Selection" on the Options bar, and simply draw a loop round the offending area to remove it.

3) Choose Select > Modify > Expand (1 pixel). This will ensure a smoother blend into the background sky. 

4) Click on Edit > Copy. You can now paste the selection into another image as a new layer, and position it with the Move Tool (V). Repeat these steps for any other images until you've built up your composite. (To save time, and to ensure consistency, I would leave any Levels or colour adjustments until after you've assembled the composite, rather than performing them on each individual image.)

Note: It's also worth pointing out that if you publish your finished work online, it's good practice to include the word "composite" somewhere in the title, lest anyone should think you really did capture four Alpine Swifts in a single shot...

Alpine Swift (composite), North Foreland, April 2010