Curve Flipping
A correction curve for digital negatives that is meant to be used on a positive image before inverting to a negative should not be confused with a curve that has to be applied to an allready inverted image. There are two ‘schools’ of curving for digital negatives. It’s like driving left or ride side of the road. In both cases you will arrive from A to B but you should never mix the method.
Anyway, sometimes it comes handy to change a ‘use before inverting’ curve into an ‘use after inverting’ curve. For example when you want to build your curve into a QuadTone Rip profile.
This can be done with the Curve Merging technique and photoshop raw file method described here.
To flip a curve you open the basic photoshop raw file described in the curve merging article and do the folowing:
1. add an adjustment layer/invert to this file
2. add an adjustment layer/curves and load the curve you want to flip
3. add another adjustment layer/invert on top of the two other adjustment layers
4. flatten the layers
5. save as: flipped_curve.amp or any name you like
6. open a file and load your curve
7. to change from .amp to .acv click on the pencil symbol in the curves palette and save the curve again
