Remove Color Cast: Levels & Curves Tools

Step 3: Select The White Point

We will do the same operations for the white (bright) point:

1. Duplicate the background layer;
2. Select the Background copy layer;
3. Open the Threshold tool;
4. Make sure the Preview is checked;
5. Move both sliders to 255 (to the right, or enter 255 in both text boxes);
6. Move the black slider to the left until a useful amount of white pixels are displayed in the image (in this case are enough pixels at 255, no move is needed);
7. Click OK to apply and close the threshold tool;
8. Choose a white point and drag horizontal and vertical guide lines from rules which should intersect over that point.
9. Place a sample point (keep Ctrl pressed while clicking on the ruler, than drag the sample point over the guide lines intersection);
10. Delete or hide the copy layer.