Roger,
if this is right "I remain unconvinced that the same “shadow separation”
can’t be achieved though plain “M0” measurements and the use of some
curve adjustments in Photoshop", in fact I don't see any reason why this
wouldn't work. This is exactly my first idea to find a work around and
since ounce we have a global adjustment in PS that does the job, we can
save this or those adjustment as an abstract profile we can then
integrate it in the profile using Argyll tools. I don't recall which
version Photoshop save these abstract profile in, we need to know at
some point.
To me this would be a trial and error approach and I'd prefer a more
methodical approach, unfortunately I have no idea how to proceed.
Thanks Roger,
Yves
On 12/16/2019 3:50 PM, graxx@xxxxxxxxxxxx wrote:
I think I still have a Spectroscan with a polarizing filter I might be able to resuscitate to do comparative testing on a “rag” or “matte” finish paper, one of these days. I agree with you that the Roman16 “dark image” showed better shadow detail on the M3 vs M2 images (on the Luminous Landscape site). Still, call me stubborn, but I remain unconvinced that the same “shadow separation” can’t be achieved though plain “M0” measurements and the use of some curve adjustments in Photoshop…. But that’s me, Yves. I don’t know Argyll’s many profiling options enough to tell you how to achieve this “separation” through some of its profile generation options…
Maybe others would know…
/ Roger
*From:* argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> *On Behalf Of *Yves Gauvreau
*Sent:* December 16, 2019 3:37 PM
*To:* argyllcms@xxxxxxxxxxxxx
*Subject:* [argyllcms] Re: Can we control the shadows (was black point compensation)
Roger,
one of us as the wrong image, the text I have below mine is "Figure 79. 30 Neutrals PD Etching ABSCOL; Custom M2 (left) vs. OEM M3 (right)"
Yes, both" ABSCOL" but one with and one without the M3 filter.
Yves
On 12/16/2019 12:16 PM, graxx@xxxxxxxxxxxx <mailto:graxx@xxxxxxxxxxxx> wrote:
Yves,
The two graphs shown in “Figures 79” were made from the **same**
profile, one with AbsCol and the other with RelCol.
Here’s the original text:
As this is not a proofing exercise for measuring dE values, one
may implement this test using different Rendering Intents (RI) to
see what difference they make to predicted outcomes for real-world
photographs. I have chosen to use two RI – Absolute Colorimetric
(ABSCOL) to see how the printer reproduces unadjusted file values
(as in proofing) and Relative Colorimetric (RELCOL) + Black Point
Compensation (BPC) to see how the printer reproduces adjusted file
values per the standard RELCOL +BPC rendition in Photoshop.
Normally we print real photos with either Perceptual or RELCOL,
not ABSCOL, so it’s important to see what RELCOL or Perceptual
would do to the appearance of shadow detail in a printed photo. I
chose to work with RELCOL + BPC, as it does less shifting of
in-gamut values and many prefer this RI. I could rerun these tests
with Perceptual RI, but in light of my findings below, I think
perhaps not really necessary. The usual advice for printing is to
try both.
Figures 79 and 80 show the graphs for ABSCOL and RELCOL respectively.
/ Roger
*From:* argyllcms-bounce@xxxxxxxxxxxxx
<mailto:argyllcms-bounce@xxxxxxxxxxxxx>
<argyllcms-bounce@xxxxxxxxxxxxx>
<mailto:argyllcms-bounce@xxxxxxxxxxxxx> *On Behalf Of *Yves Gauvreau
*Sent:* December 16, 2019 12:13 PM
*To:* argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
*Subject:* [argyllcms] Re: Can we control the shadows (was black
point compensation)
Here a link to a copy of the page and hopefully all the images and
what have you, it's also a Mark Segal article.
(https://www.dropbox.com/s/4q4tnu4pkowhaep/test.zip?dl=0)
I guess I'm not the only one not to read every thing that is
thrown at me LOL
I agree with you that it would be instructive as I already did
read it. I just verified, and figure 79 image is in the folder so
everyone should see it.
I'll repeat how those graph where made, both have the same
original test image ( grey patches with L* values from 1 to 30),
so same input, same printer, same paper, etc. The only thing
different is the*"profile"*, the one used for the left graph was
printed with a profile done without using the M3 filter and for
the one on the right, a profile made with an M3 filter.
This kind of prove that "good" profile can be made at minimum
using an M3 filter instrument.
Can we trick a profile to give us results as if it was made with a
M3 filter? If so how to proceed with Argyll of course?
Yves
On 12/16/2019 11:27 AM, Alan Goldhammer (Redacted sender
agoldhammer for DMARC) wrote:
I think you are asking too much of the profile when you should
be focusing on image processing. I’m pretty sure I posted
this already:
https://forum.luminous-landscape.com/index.php?topic=118349.0
There are four pages of discussion about the Chromix made
profile and from users such as myself. On page three, Graeme
weighs in on the use of M3 measurements. Doug Gray and Mark
Segal (the author of the paper review) who both have done lots
of profiling also weigh in on this. It would be instructive
to read that. If you are content with the high gamut Chromix
profile, why don’t you just use it rather than trying to use
Argyll to create a profile that won’t give you the same type
of result. You won’t be able to replicate what Chromix has
done with your hardware.
I let my subscription to Luminous Landscape lapse as I no
longer found the new articles of any interest so I cannot
access the figure you mentioned.
Alan
*From:* argyllcms-bounce@xxxxxxxxxxxxx
<mailto:argyllcms-bounce@xxxxxxxxxxxxx>
[mailto:argyllcms-bounce@xxxxxxxxxxxxx] *On Behalf Of *Yves
Gauvreau
*Sent:* Monday, December 16, 2019 10:09 AM
*To:* argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
*Subject:* [argyllcms] Re: Can we control the shadows (was
black point compensation)
I'm not trying to print darker blacks, on whatever paper. This
would be a humongous waste of time and resources.
I obviously don't use the same language as you guys it would seem.
On figure 79 on the left side in particular, for any input
below L* 12 the output or print value I get is the almost the
same at L* just above 16 (that's bad, a waste, etc). What I
want is a way to make a profile that would print for the same
input as on the left side, a response or a print value that
increase as much as possible relative to increases in input
values, just like on the graph on the right side of figure 79.
Regards,
Yves
On 12/16/2019 9:41 AM, Alan Goldhammer (Redacted sender
agoldhammer for DMARC) wrote:
Printer manufacturers write drivers tailored to the papers
they sell. In many cases the papers are re-branded from
major suppliers. Unless you purchase a RIP, you are
hostage to what the printer manufacturer provides.
Sometimes they will update firmware and drivers as Canon
recently did for Barayta papers, providing a new setting
that can be used. With my old Epson 3880 there were
driver tools to adjust ink density within some limits.
I’ve not looked at my Canon Pro-1000 to see if the same
feature is available. Even with the Epson settings, I
never found that I had to do any adjusting and of course
one will have to reprofile everytime ink densities are
changed to deal with potential color shifts.
Some years ago, Scott Martin provided a nice test chart
that allows one to look at various paper settings and pick
the best setting. As he says, “Compare the final prints
for maximum black density (DMax), color gamut, shadow
detail and dot smoothness. You’ll want to choose the media
selection that delivers the best DMax without losing a
significant amount of shadow detail (loosing 5% or less is
OK), or without a course dot pattern caused by what I call
“micro pooling” (where dots touch due to excessive ink).”
You can find the print chart and further information here:
https://www.on-sight.com/how-to-determine-the-optimal-media-selection-for-any-paper/
this does what Greg describes in his email response to
Yves. I’ve used this chart over the years every time I
try out a new paper. In all but one case, I found the
paper manufacturer’s suggested settings to be the best one.
Ultimately, bringing out shadow detail is really a
function of the digital image processing. As I noted
earlier and provided some good references, soft proofing
is a key part of this process. What you see on your
computer screen in the absence of soft proofing is
misleading as the screen gamut can be quite different from
the paper’s.
Alan
*From:* argyllcms-bounce@xxxxxxxxxxxxx
<mailto:argyllcms-bounce@xxxxxxxxxxxxx>
[mailto:argyllcms-bounce@xxxxxxxxxxxxx] *On Behalf Of
*graxx@xxxxxxxxxxxx <mailto:graxx@xxxxxxxxxxxx>
*Sent:* Monday, December 16, 2019 8:43 AM
*To:* argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
*Subject:* [argyllcms] Re: Can we control the shadows (was
black point compensation)
Thank you Greg. That’s the point I was trying to drive.
I know that “more ink volume” does not “necessarily”
translate into “higher dmax”, I know. There is a point of
“diminishing returns”, just as in micro-economics. Your
suggestion to use a small chart is right on the money.
/ Roger
*From:* argyllcms-bounce@xxxxxxxxxxxxx
<mailto:argyllcms-bounce@xxxxxxxxxxxxx>
<argyllcms-bounce@xxxxxxxxxxxxx
<mailto:argyllcms-bounce@xxxxxxxxxxxxx>> *On Behalf Of *Greg E
*Sent:* December 16, 2019 8:38 AM
*To:* argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
*Subject:* [argyllcms] Re: Can we control the shadows (was
black point compensation)
In the past I ran a printer on a real RIP, had control way
past normal ink volumes. More ink does not equate to
darker dmax. In reality once you go too far, the dmax
starts to get lighter again. Doesn't really answer the
question of what the Canon driver will let you send.
Also in the past, helping other people with their
profiling, we would have them print a small chart using
several different printer settings, selecting different
types of paper in the driver. Then you measure all the
samples to find the one that gave the best results and
print the larger profile target. Since we don't have
control over ink limits, this is about the only way to
vary the amount if maximum ink on paper.
