QTR-Quadtone RIP

David

No, the calibration process should be done for each printer/ink/paper 
combination. Different papers can take different amounts of ink and the 
main purpose of the calibration is to guage the level of black ink which 
provides the best dmax as well as the 'crossover' points for the black & 
grey inks.

Printing the initial 100% calibration will give you the full range from 
5%-100% coverage. Dmax can actually decline with overinking and the best 
dmax patch will almost certainly not be the 100% one.

My experience shows that, even using the Media Type of Matte Paper, 
there are no papers, matt or gloss, that can take anything like the 
amount of ink deposited in the 100% patch at the 100% calibration limit 
at 2880dpi. The Matte paper setting therefore provides more than enough 
latitude in terms of quantity of ink deposited.

Media Type may determine other factors (?platen gap ?drop size) that 
might be factors but the evidence is inconclusive. Hopefully more people 
will reply to the other David's thread in this regard.

regards
Howard

--
Howard Shaw
www.howardshaw.org

dmwket wrote:
> Howard,
> It is my understanding from reading the material that the Ink Separation calibration is a 
> printer specific, not paper specific calibration.
> 
> I did that calibration before starting the per paper profiling I described.
> 
> It is important to remember that that has to be accomplished as well. Thanks for pointing 
> it out.
> 
> What drove me to doing the detailed profiling I described here is the lack of Dmax with 
> the default matte paper selection even after doing the Separation calibration.
> 
> Regards,
> David
> 
> 
> --- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:
>>
>> This method may work if the best black ink density for the new paper 
>> matches that of the paper whose existing profile you use.
>> 
>> However a better way to optimise dmax and take out some of the guesswork 
>> is to standardise on one paper setting & resolution and print one of the 
>> ink separation tifs in calibration mode. See the file 'QuadToneRIP User 
>> Guide.pdf' in the qtr folder for more details.
>> 
>> Howard
>> 
>> 
>> dmwket wrote:
>> > Alan,
>> > Linearization is done on a per paper basis.
>> > 
>> > It is the profile used by QTR for that paper.
>> > 
>> > Based on experimentation and reading here on this forum I arrived at the following 
>> > process;
>> > 
>> > 1) Select an existing profile text file that approximates the paper you want to profile 
> and 
>> > delete the Linearization line at the end of the file and save with a unique name.
>> > 
>> > 2) find the best Dmax by printing 100% black squares with several paper settings i.e. 
>> > Premium Gloss Photo Paper, Premium Luster Photo Paper, etc. at 1440 as well as 
> 2880 
>> > using the file you created in 1 for the curve.
>> > 
>> > I positioned the ink swatch on the paper by clicking center image off and then setting 
> a 
>> > margin to create a row of swatches at the various setting.
>> > 
>> > These samples are all printed with No Color Management set in the printer dialog.
>> > 
>> > This is tedious but important. I let the samples dry for about 2 hours before reading 
> them 
>> > with my Spyder Spectrometer.
>> > 
>> > 3) Once the best Dmax paper, resolution setting is found. use that paper and 
> resolution to 
>> > print the 21 X 4 step wedge using the curve created in 1.
>> > 
>> > 4) Let the test print dry for a minimum 2 hours, over night is optimum, then read it 
> and do 
>> > the linearization.
>> > 
>> > 5) Copy the Linearization line from the text file and paste it into the file you made in 
> 1 
>> > above and save the file as your curve file for the paper.
>> > 
>> > 6) Copy the file into the printer profiles folder and "install the printer".
>> > 
>> > 7) Once the curve is installed I save a preset for QTR that has the paper selection, 
>> > resolution setting and curve. I name the preset to reflect what paper it is to simplify 
> my 
>> > printing.
>> > 
>> > 
>> > Trust this helps.
>> > 
>> > There may be a better way to do this that someone more experienced can offer.
>> > 
>> > Have fun learning QTR --- the B&W prints it produces are great.
>> > 
>> > Regards,
>> > David
>> > 
>> > --- In QuadtoneRIP@yahoogroups.com, "handyman856" <avr@> wrote:
>> >>
>> >> Is linearization done on a 'per printer' basis, done once with any
>> >> paper for a given printer, or is done 'per paper', and part of the
>> >> profiling process of each paper?
>> >> 
>> >> =Alan R.
>> >>