QTR-Quadtone RIP

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 <ross.jarvis@...> 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