QTR-Quadtone RIP

Thank you Roy

This highlights another issue which is confusing me.

My understanding is that the ink separation. tif needs to be printed without colour management, so is in a way an "absolute" test.  For this I use QTR print tool.  However I thought that the step wedges were "subjective" and prints for linearisation were to be done through the process most like that of my normal workflow, so I've been doing these through Elements.  As you mention "No Color Management" appears not to be an option through Elements 11 on a Mac.

Should I be printing step wedges for linearisation through QTR Print Tool?  

As mentioned earlier, I am not yet happy with the printing of shadows/blacks, particularly at the 90%+ values, and also the linearisation "bulls eyes" show rings and unevenness.

Might I be getting too involved in the detail here?
Do these tests show some of the limitations of UT14, particularly with profiles only using 2 inks?

regards

Ross

--- In QuadtoneRIP@yahoogroups.com, Roy Harrington  wrote:
>
> The Info palette can be deceiving if you are not careful.   It only
> reports the contents of the file
> where the file type matches.  In other words grayscale file => look at
> K, RGB file => look at RGB.
> The others are all color managed conversions based on the default
> working profile set in Color Settings...
> 
> So what you are seeing in the RGB values is the conversion of working
> gray to working RGB.
> And the Lab values I think you are looking at are based on the working gray.
> 
> All step wedges ought to be untagged and evenly spaced.  (and I'd bet
> any you find on major site are).
> If you are on a Mac, printing targets with No color management is a
> bit tricky unless you use Print-Tool.
> 
> Roy
> 
> 
> On Tue, Feb 12, 2013 at 9:46 AM, rossfmj  wrote:
> > I am still having problems profiling UT14 to Epson Premium Glossy Photo Paper, particularly with setting the default ink limit and getting blocking up in the blacks.  I'm thinking I may be having a problem linearising the profiles.  In order to get my head round what is going on I have been checking the 21 Step Wedges I was using, one is a tif in the Eye One folder, and the other was from Paul Roark's website; http://home1.gte.net/res09aij/21-Step_GG22_L5.tif (marked for Gloss Paper).
> >
> > Both of these show to not be linear in values for the graduations.  Values I get (% and on 255 8Bit Luminance Scale) are;
> >
> > Black 100% is 100% (0), 95% is 98% (5), 90% is 92% (19),  85% is 87% (33),  80% is 81% (48), 75% is 76% ((62).  The Luminance values do not match the figures on Paul's test strip.
> >
> > I have also checked a 21 step wedge from Keith Cooper's site, this does match the % values.
> >
> > Have these wedges been created with a conversion factor to open up the blacks in linearisation?
> > Have I been using the wrong wedges?
> > Which wedge should I use for linearisation?
> > Is there a problem occurring in Elements when I open the images?
> > Might there be something else I am doing wrong?
> > Should I get my camera, enlarger and darkroom kit back from whom I gave it to?
> >
> > regards
> >
> > Ross
> >
> >
> 
> 
> -- 
> Roy Harrington
> roy@...
> www.harrington.com
>