[argyllcms] Re: DTP20 (Pulse) patch size error

  • From: "Philip Reed" <philipreed@xxxxxxxxxxxxx>
  • To: <argyllcms@xxxxxxxxxxxxx>
  • Date: Fri, 19 Aug 2011 03:14:28 -0400

Hi Graeme,

Thank you for the detailed explanation.  I can appreciate the many
contingencies that have to be accounted for and coding for all of them would
be almost impossible.  I'd like to add that I hope you didn't take my prior
message as a criticism...just a question because I don't understand the

The problem I'm having seems to have been solved...and of course...it's user
error!  I read a post that said it's not really possible to print the chart
in Photoshop CS5 and completely disable colour management. A solution is to
use the Adobe Color Print Utility.  However, I've found that this utility
does not seem to print the chart 1 to 1 but shrinks it a little.  I tried
other programs and ran into other scaling issues.  Printing the EPS in
Illustrator or the TIFF in Photoshop, results in no scaling issues.  I'm
pretty sure that a document without an embedded profile can be printed from
Photoshop without color management if no profile is assigned.  If I'm
wrong...please let me know.

Thanks again for a great piece of software, your patience and help!


-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Graeme Gill
Sent: Thursday, August 18, 2011 9:47 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: DTP20 (Pulse) patch size error

Philip Reed wrote:
> I'm wondering why you didn't use the same sizes and configuration as the
> charts produced by X-rite software? They have 29 patches per row and each
> patch is 6.7 x 12mm.

        I followed X-Rite's documentation on creating the charts,
and fitted it into Argyll's existing chart printing code.
The documentation specifies exactly 6.5mm, which is what the PS and TIFF
files contain. My experience was that (for instance) using 6.5 mm patches
for the TID did not work, indicating that the documentation
needed to be followed precisely, which is what I did.

I have no information at the moment on what tolerance the
device will handle in this regard, or even if this is the issue at hand.
Combine that with (apparently) printers that aren't at 100% scale,
and it's hard to know which way to go. Should I add a fudge factor
of 0.2 mm, assuming that the device can handle larger but not
smaller patches ? If I do, what happens when someone prints the chart
on a printer running at 103% scale, and the patches come out at
6.9mm ? Will the instrument read them ?

It could be something else, such as the density of the start & stop bits.
The documentation says CMY 30/30/30 or 50/50/50, which is a little
ambiguous. How critical is it that it be CMY (ie. ink limiting) ?
What about RGB printers ?

Graeme Gill.

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