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.
On 10/3/08 20:03, "Kees Brandenburg" <email@example.com> 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:
> 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.
> 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.
>> On 10/3/08 18:44, "Michael Koch-Schulte" <firstname.lastname@example.org>
>>> 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.
>>> On Mon, Mar 10, 2008 at 6:53 AM, Henry Rattle <email@example.com
>>>> 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."