put them in layers and change the top layer mode to difference.
Thank you for your fast reply. i will look into that.
Much appreciated.
Research for a future CSI episode?
Or to have a mask ready, use image>calculations
Yes, Image > Calculations > Subtract.
Here one can choose Offset (128px) and Scale (e.g. 1).
‘Subtract’ shows the signed difference with respect
to Offset.
‘Difference’ shows only one half of the signed
difference with respect to black (more black is ignored).
Best regards –Gernot Hoffmann
The fingerprint mark is perhaps not visible
in the medium gray Subtract result. Then use
a steep curve, centered at 128.
G.H.
The explanation of ‘Difference’ was wrong.
Help text:
"Difference: Looks at the color information in each channel and subtracts either the blend color from
the base color or the base color from the blend color,
depending on which has the greater brightness value.
Blending with white inverts the base color values;
blending with black produces no change."
G.H.
Thats different that what I was thinking. I would assume white blending with black would show a change. Apparently the base has priority. Huh. Go figure.
"…I would assume white blending with black would show a change. Apparently the base has priority. Huh. Go figure…"
The Difference blend produces the absolute value of the differnce between top and bottom values. Black’s value is ZERO. Go figure.
