User:Dschwen/PDRI

A little test at salvaging a lost cause...

...or: how to increase perceived dynamic range.

Original. Difficult lighting conditions.

Increase of the perceived dynamic range

1. Open the image and duplicate the original layer to have it three times
2. Leave the bottom layer untouched
3. For the second layer create a layer alpha mask from a grayscale copy of the layer
4. For the third layer create a layer alpha mask from a grayscale copy of the layer, but invert the mask
5. Gaussian Blur both layermasks (r=25px)
6. Use the curve tool the increase the contrast of the masks. Keep only bright parts.
7. Gaussian Blur both layermasks (r=25px) again
8. In the second layer (image, not mask) increase the contrast in the bright part of the histogram.
9. In the third layer (image, not mask) increase the contrast in the dark part of the histogram.
10. flatten image
11. done

Drawback is a noise increase depending on the amount you pull up the contrast in the two additional layers. Use good judgement. (Not like in the extreme example above).

Examples

• 
  Opera House, Hannover. Darkend sky, lightened foreground
• 
  Landscape Arch, Utah. Darkend sky, lightened foreground