Painting With Colour Using LAB Colour Space

  1. Open an image that needs its color punched up a bit.  We will call this the RGB Copy
  2. In Photoshop create a duplicate image.  Change the mode of the duplicate image to LAB.  Call this the LAB copy.
  3. In the channels pallet select the b (yellow - blue) channel.
  4. Equalize the b channel.
  5. In the channels pallet select the LAB image.  This image will have the yellows made greatly more yellow and the blues greatly more blue.
  6. Copy this image in the LAB copy.
  7. Paste this image to the RGB copy.  This will be a new layer which you should name Equalized b.
  8. Add an opaque (black) mask to the Equalized b channel.
  9. Select the paint brush tool, make the brush soft and the opacity somewhere between 5% and 10% and let the foreground color be white.
  10. Paint white on the Equalized b layer mask where you wish to increase the yellows or where you want deeper blues.

  11. Go back to the LAB copy to repeat the above steps with the a channel.
  12. Undo all steps previously taken in the LAB copy (multiple ctrl Z's or undo all steps with the history pallet)
  13. Select the a (magenta - green) channel then equalize the a channel.
  14. Select the LAB image then copy and paste this image to the RGB copy.  Name the new layer Equalized a.
  15. Paint white at 5% to 10% on the equalized a channel where you want more magenta or more green.

  16. We can add contrast to the original.  Go back to the LAB copy, undo all steps and select the lightness channel then equalize.
  17. Select the LAB image then copy and paste the image back to the RGB copy.  Name the new layer Equalized lightness.
  18. Change the blending mode to something in the from overlay to hard mix in the blending mode drop down menu.


Resources for Photoshop and Lightroom tutorials
  1. Kelbytraining.com -- subscription site
  2. Lynda.com -- subscription site
  3. AdobeTV -- free tutorials from Adobe
  4. Jullianne Kost --  Principal Digital Imaging Evangelist  from  Adobe
  5. The Russell Brown Show 
  6. YouTube