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

OK but with making the digital negative for monochrome prints "linear" is what I want. If I want to do any tone-mapping using advanced algorithms in 32-bit HDR I'll apply that to my RAW negative in Camera Raw or perhaps the camera manufacturer will build the algorithm into the next model of Leica camera (the M10 due out in 2062) ;^) and I'll select it as an effect from a menu. That's what the technology outlined earlier in that paper is destined to be used for. It's interesting but well beyond the need of a reflected print. A transmissive positive...perhaps. (Now you've got me thinking about that Jeff Wall guy again. Maybe he's onto something. Urrrg.!) I really think it's an apples an oranges argument.


On Mon, Mar 10, 2008 at 8:29 PM, Yves Gauvreau <gauvreau-yves@cgocable.ca> wrote:
this idea of custom ICC profile is excellent, it would solve quite a few problems except one. Because prints in general have less dynamic range then your originals, someone as to decide which part or parts of the original range will have to be sacrificed or more positively which will need to be enhanced somewhere in the workflow. Basically it's tone mapping again. Suppose this profile maker exist, then with experience someone could learn how to prepare each original to get the best out of it when printed. I suspect that those using current methods do exactly that knowingly or intuitively but they attribute this to the method instead of their experience unfortunatly.
----- Original Message -----
Sent: Monday, March 10, 2008 5:00 PM
Subject: Re: curves and gum and Christopher James book

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."