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Using ICC profiles for making digital negatives?

Using ICC profiles for making digital negatives?

2015-02-10 by sanking@...

Any ideas on how to use Roy's QTR-Create ICC to print digital negatives? I have been using QTR-Linearize-Data, which allows one to invert the Linearize/Lab values to apply to digital negatives, and then installing the .txt file. Is there any way to invert the L values in the ICC profile?


Sandy

Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-10 by Roy Harrington

Hi Sandy

I don't do digital negatives but this is the concept that I think should work.

I look at the QTR driver level all to be in the "negative" space -- i.e. fed negative values and print negative values.
As I think you get it, the Linearize is based on reading the "positive" output from whatever alt process you print with.
This is known by QTR driver curve generator because of the reverse order of L-values. The correction curve is
flipped and backwards because of being in "negative" space.

I see the ICC profile level entirely in positive space -- applied to the positive image based on the output of the positive print.
With all the steps: inversion, neg QTR driver printing, pos alt print -- looked at as one big black box.

On the Mac with Print-Tool this is simplified:
Print-Tool does these in order: applies print profile, negative/flip, QTR driver prints neg.
On a PC you need to do these manually in Photoshop and then QTRgui.

(making the ICC do the invert is a tempting idea but you still need the flip, and I'd be worried about the
inverted ICC messing up some CMS workflows)

Roy
Show quoted textHide quoted text
On Tue, Feb 10, 2015 at 8:22 AM, sanking@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


Any ideas on how to use Roy's QTR-Create ICC to print digital negatives? I have been using QTR-Linearize-Data, which allows one to invert the Linearize/Lab values to apply to digital negatives, and then installing the .txt file. Is there any way to invert the L values in the ICC profile?


Sandy






--
Roy Harrington
roy@...
www.harrington.com

Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-11 by sanking@...

Hi Roy,

I would like to follow your suggestions, but something odd is happening in Print Tool when I click on Negative to invert and flip. The image itself (a 7" size file of the 21 step tablet) is inverted as expected, from 0% to 100%, but then the entire rest of the 8.5" X 11" page is filled with 100% density?

I am using Print Tool 1.1.0, with MAC OS 10.9.5.

Sandy

Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-11 by sanking@...

I am uploading (to the Files Section, "Print Tool Invert") a screen grab of the Print Tool page, after the file has been inverted. As you can see, the image file, which is about 7" X 2", has been inverted (not flipped, but that is another story), but the rest of the 8.5" X 11" page, inside the margins, has been filled with 100% density. This also prints!!

What am I doing wrong? I can not figure out why the inversion impacts the entire page, not just the image file!!

Sandy

Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-11 by Roy Harrington

Yes, that's right. (that's what Photoshop does too).
The idea being that you'd want a white border on final print.
Maybe it could be an option I guess if I can find a place to put it.
The flip happens at output so does not show on screen.

Roy
Show quoted textHide quoted text
On Tue, Feb 10, 2015 at 7:57 PM, sanking@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:


I am uploading (to the Files Section, "Print Tool Invert") a screen grab of the Print Tool page, after the file has been inverted. As you can see, the image file, which is about 7" X 2", has been inverted (not flipped, but that is another story), but the rest of the 8.5" X 11" page, inside the margins, has been filled with 100% density. This also prints!!

What am I doing wrong? I can not figure out why the inversion impacts the entire page, not just the image file!!

Sandy




--
Roy Harrington
roy@...
www.harrington.com

Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-11 by sanking@...

OK, thanks for the explanation. I had not seen this aspect of the inversion discussed before and feared there might be some glitch in my system.

I have been able to verify that the concept you suggested works, and in a comparison test in practice produced a digital negative with very close to the density range and curve shape as when linearizing with a QTR profile.

Sandy


Re: [QuadtoneRIP] Using ICC profiles for making digital negatives?

2015-02-16 by sanking@...

i1 Profiler Version 1.5 seems to offer a good alternative to the Measure Tool for QTR grayscale measurements with post MAC OS 10.6.8 systems (I am using OS 10.9.5). I installed the i1 Profiler program and placed Scott Martin's gray scale work files in the indicated folder, and after a bit of navigating was able to calibrate the device and measure a printed QTR 21 step reference target, drop the .txt file on QTR Linearize Data and derive the Linearization data for a QTR profile. Scot suggested using Spot with the iOne Pro, but I used Line and the scan worked the same way as it does with the Measure Tool.

Sandy

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