Re: curves and gum and Christopher James book
Kees - Thank you. What I found puzzling was how similar the shape of David's "before inverting" curve is to my "after inverting" curve. I somehow felt they should be different, so that one curve would look something like the inverse of the other. H On 10/3/08 20:03, "Kees Brandenburg" <ctb@zeelandnet.nl> wrote: > Hello Henry, > > A correction curve 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 a bit 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 methods. > > Anyway, sometimes it comes handy to change a 'before inverting' curve > into an '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 described here: > http://polychrome.nl/weblog/curve-merging > Actually you will not merge two curves here but you 'wrap' a curve > layer with your curve loaded between two invert layers. Then you have > to flatten this package and save the .raw file as a .amp curve. When > you load that curve you can change it to a regular .acv by clicking on > the pencil symbol in the curves palette. When I find some time this > week I'll write an article about this on my site. > > Kees > > > On 10 mrt 2008, at 20:09, Henry Rattle wrote: > >> Michael you are right, of course. But my question was more about >> shouldnąt a curve that you apply to a positive, curve in the >> opposite direction from one you apply to a negative? >> >> Davidąs curve, like mine, has the shadows in the bottom left corner. >> >> H. >> >> >> On 10/3/08 18:44, "Michael Koch-Schulte" <michael@mondotrasho.ca> >> wrote: >> >>> Henry, it all depends how the curve data was gathered in the first >>> place. Neither is right or wrong it's more a matter of workflow. I >>> choose to apply my curves to the positive because I'm taking my >>> readings from a developed positive. I also like to work in PS with >>> the curve putting my highlights in the bottom left corner using the >>> graphic scale of 0-100 rather than the binary scale of 0-255. The >>> important thing is that you apply the curve to the image at the >>> correct stage of the procedure. Dan Burkholder started doing it >>> this, I also do it this way. It intuitive for me. Others apply the >>> curve to the negative. >>> ~m >>> >>> >>> On Mon, Mar 10, 2008 at 6:53 AM, Henry Rattle <henry.rattle@ntlworld.com >>>> wrote: >>>> However one thing puzzles me - there's a note alongside the curve >>>> which says >>>> "Note from David: The curve is applied before inversion to a >>>> negative and >>>> the image should be RGB." >>>> >>>> >>>> Henry >>>> >>>> >>>> >>>> >>> >>> >> >
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