QTR-Quadtone RIP

chiaro2112 wrote:
> Hi Everybody Im a newbie in here, 
> Sorry if my english is not very good, im also have question about QTR Create ICC/ICC RGB. I 
> love this feature because finally im able to Soft Proofing Epson ABW.
> If im not wrong (please correct me if im wrong), the function of QTR create ICC is to Linearize 
> data and then make icc Profile based on linearize data. How if i want to make ICC profile 
> without Linearized the data , so i can softproofing Before and after Linearize result in 
> Photoshop? if it not posibble, There is another method for doing it?
> 
> Thanks Everybody,


No, the QTR create ICC is to represent your printer output 
in PS and adapt your image tone range to the tone range 
possible between the Dmax and paper white of the paper you 
made the profile for. You have to make or find a linear 
output of your printer first.

Find an ABW driver setting that will deliver a linear 
output. You can test that with the 21 or 51 step greyscale 
targets. You have to check whether the Dmax doesn't run back 
on the 100% patch compared to a lower one as that sometimes 
happens. If the driver allows some ink limiting like my HP 
Z3100 you can use that to bring the highest Dmax on the 100% 
patch. Otherwise you could use the gamma function of 
lighter/darker in the driver to make the output more linear, 
a clumsy approach but there's no alternative. You have to 
keep that setting then when printing later on.

When the printer's output is linear you can make the profile 
with the same target.

For consistency in time you can not go back to a new 
linearisation of the printer output like possible with QTR 
or the internal calibration of the HP Z3100.  There's 
Colorbase for calibrating some Epson wide formats but you 
didn't mention the model.

If it is difficult to get the printer linearised you better 
use the QTRip itself. A profile based on a non linear 
printer output doesn't really help to get your shadows 
correct etc. In that case you probably have more help from a 
correction curve in PS if you want to stay with ABW.


-- 
Met vriendelijke groeten,  Ernst


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