Begone, purple fringing!
May 18, 2006. Photoshop.
Purple fringing rears its ugly head in high contrast situations, such as leaves against a bright sky.
In this picture of the Bow River in Calgary, there is a lot of purple fringing in the sky that will soon disappear! It's not hard to fix, but it takes some artistic skill.
With the eyedropper, sample the colour of the darker object that is being fringed. In this case it was the green leaves. Darker or more neutral colours will look more realistic.
Choose the paintbrush tool. Pick a brush with soft edges. Put it in "color" mode as shown below. Colour mode is very useful. It keeps the greyscale value of the colour you are painting over and tints everything accordingly.
Now dab over the areas with purple fringe. Dabbing will give you better control and will look more realistic. In this image I've started on the top left part of the tree.
And there you go! That's much better!
Because the colour brush goes on the value of the colour it paints over, this works best when the sky is light and neutral.
This tutorial was done in Adobe Photoshop CS2.