Digital BW, The Print

"fogmarco" <marco.fogarolo@...> wrote:
>
> I'm printing ... UT14 and icc profiles 
>(i find very good ... with Photo Rag and Epson archival matte ...

> ... on Ilford Gold Silk ... glossy paper 
> ... I'm tring to understand how I have to use this kind of papers.



> ... if I read a 21 step printed with this acv curve 
> I obtain these values:

> 4,05	-7,13	-9,53

> 96,70	2,17	-3,34
> 91,57	2,16	-3,12
> 85,44	2,22	-2,95
> 80,36	2,50	-2,40
> 74,96	2,63	-1,86
> 69,55	2,83	-1,31
> 64,16	2,95	-0,87
> 59,14	3,14	-0,27
> 54,04	3,40	0,27
> 49,73	3,56	0,94
> 45,46	3,96	1,32
> 41,57	4,04	2,11
> 36,61	4,09	2,85
> 31,31	4,69	3,49
> 25,71	4,85	3,17
> 21,65	4,98	2,50
> 17,78	4,59	1,61
> 13,64	4,45	0,53
> 11,18	4,65	0,70
> 11,08	3,57	2,37
> 
> I think that the numbers on first line are not correct.

I agree.  I'm not sure where they are from.  The Lab L for the paper would be about 96.

What can occassionally happen is that if the paper is brighter than the calibration tile, the system gives some odd results.  Sometimes ink from the papers or other cause can affect the tile.  I think it can be cleaned, but C. David Tobie is the one who can best answer this issue.

 
> I have another little question: for making icc profiles 
> I start with a 21 step file in RGB mode. 

And RGB space set to Adobe RGB (1998) hopefully ...


> This mode I need for the color separation acv curve.

> The ICC profile that i obtain from this file can be 
> used also for printing gray scale file or only RGB files?

I use aRGB to make the ICC using Create ICC-RGB (QTR download), but I print my grayscale files with the resulting ICCs.  I believe the first thing the ICC will do is convert an RGB file into a grayscale file.

By the way, be sure with glossy papers and UT14 to turn off the Eboni by having one of the curves totally off at 100% black.  You can use any combination of the UT14-C and UT-14-M (PKn and PK, controlled by the red and green PS curves, respectively).  If you use both, then be sure the blue curve (Y position glop) is totally turned off at 100% black).  If any Eboni is released at all, the dmax will probably decrease.  I believe you'll get some gray substitution if any amount of a third ink/curve is used.  This gray substitution would be injection of Eboni MK -- to be avoided with glossy papers.

Paul
www.PaulRoark.com