U of S | Mailing List Archive | alt-photo-process-l | Re: curves and gum and Christopher James book

Re: curves and gum and Christopher James book

  • To: alt-photo-process-l@usask.ca
  • Subject: Re: curves and gum and Christopher James book
  • From: Michael Koch-Schulte <mkochsch@gmail.com>
  • Date: Mon, 10 Mar 2008 16:00:46 -0600
  • Comments: "alt-photo-process mailing list"
  • Delivered-to: alt-photo-process-l-archive@www.usask.ca
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  • In-reply-to: <C3FB37CD.C46E%henry.rattle@ntlworld.com>
  • List-id: alt-photo-process mailing list <alt-photo-process-l@sask.usask.ca>
  • References: <dfe71130803101144i5df6db2drd9097d1d2417ee12@mail.gmail.com><C3FB37CD.C46E%henry.rattle@ntlworld.com>
  • Reply-to: alt-photo-process-l@usask.ca

Yes. It should be inverted. But you have to note which "mode" the curve window is in. If you give a handful of curves a quick glance they may look the same. You have to REALLY pay attention to the curve mode being used to display the curve. A curve calculated for graphic mode (applied to a positive) will, on the surface, look exactly the same as a curve applied to a negative -- BUT since PDN users generally work in binary mode it is this change of mode which functions to invert the curve.
  In the end the effect is generally the same. Ink (read: density) is diverted via the curve toward the dark-mid tones and print shadows in the negative to compensate for printer's ink profile. When someone figures out how to take a curve and programmatically graft it onto a custom ICC profile life will becomes much simpler for digital negative "curvers" because it'll become as simple as selecting a paper in the print dialogue.

On Mon, Mar 10, 2008 at 1:09 PM, Henry Rattle <henry.rattle@ntlworld.com> wrote:
Michael you are right, of course. But my question was more about shouldn't a curve that you apply to a positive, curve in the opposite direction from one you app ly to a negative?

David's curve, like mine, has the shadows in the bottom left corner.


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 curv es 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 t hing 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 <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."