Post Processing Tip, Colour Corecction Technique

As the ranks of this forum continue to expand with increasing usage of Pentax digital equipment how's about creating a sticky with some of the more obscure/hidden/personal techniques that we use to post process our digital images.

If I may I would like to start the ball rolling with a basic one.

I’ve been recommend to change a couple of PS defaults, here they are but I will leave it up to the reader to make their own decision whether to do this or leave well alone.

First set the Eye Dropper tool to sample 3x3 pixels, click the eye dropper tool and go to the menu bar at top left of window and pick “3 by 3 average” from the drop down menu instead of “point sample”, this ensures you sample a small area instead of a single pixel.

Second thing is to set new default values for the black, grey and white point in the curves pallet. Double click the left icon (black point) of the three icons grouped in the bottom right of the curves pallet (opens colour picker pallet) for the black point and set all the RGB values to 20, double click the middle icon for the grey point and set the RGB values to 133 then double click the third icon for the white point and set the RGB values to 244, click OK and save as defaults when prompted.

Colour Correction using Curves and a “Threshold” adjustment layer

1. From the layer pallet create a new “threshold” adjustment layer, your image will turn black and white

2. In the threshold pallet drag the marker all the way to the left, your image will turn white.

3. Now drag the marker back to the right till you see the first black pixels appear and close the threshold pallet.

4. Zoom into the black pixel area.

5. On the tools menu bar expand the eyedropper icon and select the colour sample tool” (tip, in preferences select “precise” for other cursors).

6. Click “once” on the black pixel area in the image, this will mark the pixels with a small crosshaired circle with a 1 next to it.

7. Now go to the layers pallet and double click the half filled circle on the threshold layer this will bring up the threshold pallet again.

8. Drag the marker all the way to the right, your image will turn black.

9. Now drag the marker back to the left till you see the first white pixels appear and close the threshold pallet.

10. Repeat 5 and 6, this will mark the pixels with a small crosshaired circle with a 2 next to it.

11. Delete the threshold layer, the 2 marks should still be showing in the image.

12. Open the Curves pallet.

13. In the curves pallet select the “black point” icon, move the cursor directly over the centre of the area marked “1” (this is where the precise cursor comes in, when it is directly over the marked area both the mark and the cursor will disappear, also better if you zoom into the marked area) and click once. You have now reassigned the darkest areas of the image to your default black point value.

14. In the curves pallet select the “white point” icon, move the cursor directly over the centre of the area marked “2” and click once. You have now reassigned the lightest areas of the image to your default white point value.

15. In the Curves pallet select the centre of the curve and pull bit to lighten, or down to darken the midtones.

16. To remove the two marked areas select the eyedropper tool from the tools menu a select the clear button from the top menu bar.

Hope this is of some use.