FLD Filter Compensation

[David C. Warner]

(I think my first posting got lost)

Does anyone have a set of color corrections that work for taking the green color one gets when using daylight film under flourescent light? (This is intended to be the digital equivalent of using an FLD filter when taking the photo, but I didn't have a filter available.

Thanks.

Dave Warner

[Gernot Hoffmann]

David, Gary:

Here is a strategy how to apply White Balance.
This requires two adjacent test areas of about 5x5mm size
which are in reality neutral gray, preferably above 160.
Walls, white cloth and especially a white paper background.

1. Put similar images in one folder.
2. Set color picker for averaging.
3. Rectangular Selection for test area 1.
4. Histogram. Measure mean values, e.g. R=191, G=173, B=150.
5. Choose your gray, e.g. R=G=B=170 (a little clipping for Blue).
This can be averaged across several similar images.
6. Set foreground color R=G=B=170.
7. Fill area 1 (selection).
8. Invert selection.
9. Image Adjust Curves.
10. Shift R on the RIGHT side of curve, measure test area 2
until 170 is achieved, trial and error. Info shows old/new values.
11. The same for G.
12. The same for B. Test area 1 and 2 should look equal.
13. Save Curve profile.
14. OK.
15. Load the same image.
16. Load Curve profile.
17. OK. Now we have the corrected image without gray test area 1.
18. Apply the same curve profile to other images in the same folder.

Let me know whether it can be done simpler.

Best regards --Gernot Hoffmann