CA or Chromatic Aberration is “fringes” of colour along boundaries that separate dark and bright parts of an image. There are a few ways you can get rid of CA but here is an easy one for Photoshop. You can see a sample of it here in this section of a picture I took with a canon 85mm 1.2 L, a lens that often has problems with CA. You can see along with the green fringing there is also purple fringing along the edges of his white shirt.
First take a soft paintbrush and set the Mode to Color and the Opacity to 60%
Use the dropper tool and choose a colour from the side the CA is worst. Then paint along the boundry and you will see the CA disappear. Play around with the opacity of the brush and the colour you have chosen to suit your image.
Final image with CA corrected.
