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Contrast mask tutorial · 2
Desaturate and invert the overlay layer
On the image toolbar desaturate the layer
Layer » Colours » Desaturate (GIMP 2.2) Colours » Desaturate (GIMP 2.4 & 2.6)
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Then on the same toolbar invert the layer
Layer » Colours » Invert (GIMP 2.2) Colours » Invert (GIMP 2.4 & 2.6)
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You should notice the image is now a lot clearer.
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