[argyllcms] Re: Silly questions about making a printer profile, more questions.

  • From: "Derek Wells" <sigma3@xxxxxxxxxxxxx>
  • To: <argyllcms@xxxxxxxxxxxxx>
  • Date: Sat, 5 Mar 2011 23:58:31 -0000

Hi Leonard,
Depending on the printer you're attempting to profile, you only need to make
one target with targen.
Use targen option -d2 if your printer is presented as an RGB device by its
driver, and option -d4 if it's presented as a CMYK device. 
Since you mention Epson, it's most likely that you'd need to use -d2.
The number of patches you'll need to print (and measure) to get a "good"
profile depends on your own quality requirements and how "well behaved" and
repeatable the printer is with the settings you intend to operate it with. 
(For most desktop printers, that means picking, then setting and recording
the driver's media type, print quality, and colour management options to be
used when printing the profiling targets so that the driver and printer can
be set up in the same way when using the profile.)
Most of the time, the only way to find out how well behaved the printer is
with any given set of settings is to print the targets, measure them, and
look at the profile and prints produced using the profile.
From personal experience, I'd suggest starting with around 1000 patches.
With regard to paper sizes, differences in the paper size used to print the
profiling targets and the final print shouldn't have any effect, so long as
the paper used to print the targets is the same as the paper used to make
the final prints. (In the ideal world, both paper sizes would come from the
same manufacturing batch, but that's frequently not the case).
Where paper sizes will make a difference is in the scanning of the targets;
the ruler supplied with the i1 pro has a fixed size, which sets the width of
the targets. 
You could always produce a suitably sized target file:
targen -d2 -f1000 rgb-printer
printtarg -v4 -ii1 -t -pa2 rgb-printer 
this will produce a profiling target with 1000 patches spread over one A2
sized page; with a little application, that should be printable on one 16 x
20 sheet . (The target will be in tiff format: omit the -t from printtarg if
you need a postscript version.)
After printing, remember to give the target time to dry and cure; I'd
suggest leaving it for a day.
I hope this is helpful.

Derek

-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Leonard Evens
Sent: 05 March 2011 20:13
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Silly questions about making a printer profile,
more questions.

On Sat, 2011-03-05 at 11:59 -0600, Leonard Evens wrote:
> I have done this before, but it was a while back.  
> 
> The instructions for making a printer profile start off with two
> examples using targen
> 
> targen -v  -d3 -f1053 PrinterA
> targen -v  -d4 -l260 -f1053 PrinterB
> 
> Looking at what I did the last time, I did run both of them (withy
> parameters I chose).
> 
> Is it correct that I only need to do one,  or are both needed for later
> steps?   Looking ahead at the instructions,  I don't see anything
> suggesting both are needed, but I am not sure.
> 
> Also,  I have an example of a profile provided by Epson for the printer
> and paper I am going to use.  Is there some way to tell from looking at
> the profile how many samples I need to ask for in targen?   Is it going
> to be the same as the number of entries in a LUT in the Epson profile?

Targen gives recommendations for the number of patches dependent on the
paper size and includes a multiplier.   Can I assume that the 
4 x Letter recommendation would be a appropriate for a profile to  use
when making 16 x 20 prints?  Do I then  use 16 x 20 (actually 17 x 22)
sheets to make the profile?  I am using an Eye-One_Pro which allows me
to scan strips.  I don't remember how it worked, but I don't want to use
any more paper than I have to.

How much do I lose by using a profile made with letter size paper with
large prints?

-- 
Leonard Evens len@xxxxxxxxxxxxxxxxxxxxx
Professor Emeritus, Department of Mathematics, Northwestern University




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