Before
After
Step 1 – Auto Color
Duplicate your background layer with Ctrl/Cmd+J. In the Image menu use Auto Color to create a general adjustment and colour balance. Look closely at the results and toggle the new layer on and off with the eye icon to compare the before and after.
Step 2 – Use levels
If the colour still doesn’t appear totally neutral, add a Levels adjustment layer using the button at the bottom of the Layers palette. Click the drop-down menu that says RGB in the Levels adjustment and select Red. Move the middle grey slider to the left to add red, and to the right to subtract.
Step 3 – Green and blue adjustments
Select Green from the drop-down menu and slide the middle pointer left or right to adjust the image’s colour back to a normal tone. Repeat again for Blue. You can also select RGB and use the middle slider to lighten or darken the image without affecting colour. Look hard at neutral greys, blacks and whites to see if the colour is now neutral.
