[argyllcms] Re: Crushed shadow details

  • From: "Alan Goldhammer" <agoldhammer@xxxxxxxxxxx>
  • To: <argyllcms@xxxxxxxxxxxxx>
  • Date: Sat, 10 Sep 2011 20:59:15 -0400

I wouldn't worry about the reduced contrast ration if you are using your
monitor for photographic work since the contrast ratio of inkjet printers is
slightly lower than what you have.  The key thing regarding calibration of
monitors is to insure you get a print that matches your monitor and
depending on the viewing conditions next to your monitor, a number of
different possible settings can provide a match.  A useful essay on this is
at:
http://www.luminous-landscape.com/tutorials/why_are_my_prints_too_dark.shtml
Just FYI, I have a BP of 0.35, WP of 120 and Contrast Ratio of 380:1 and I
get a good match of prints to monitor when using a Solux light source
mounted next to the printer.

 

From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of xun wang
Sent: Saturday, September 10, 2011 1:40 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Crushed shadow details

 

I'm not sure if there is a default black point for argyllcms.

The x-rite profile is quite decent actually as far as I can tell, it's just
not nearly as flexible. At 6500k(my lcd's native now is ~5k) 100cd/m2 white
point, I see black level at 2, have a contrast ratio of ~780:1. I'm not sure
what the BP is for x-rite because it doesn't say. Using ArgyllCMS and BP
adjusted to 0.3/cdm2, I see BL from 1, but with a reduced contrast ratio of
~470:1.

On a similar note, I was originally planning to calibrate my i1 display 2
off the colormunki and use the i1d2 to get better shadow details because
everyone is saying that spectro doesn't perform as well as a colorimeter in
dark patches, I understand it's because of the increased noise. But so far
I'm not seeing any real world differences when I compared ColorMunki with
i1D2+CCMX in the shadow. I checked out the B&W gradient & examined the dark
patches in the shadow and didn't notice any conclusive differences between
the 2. What exactly should I be looking for? 

 

I did however see higher dE in RGB gray balance when I did cross profile
verification using both to measure against each other, not sure they mean
anything, but here you go.

 

All settings used are the same & built using high quality setting, with only
difference in hardware. For CM I turned on Adaptive Hires & BP Drift
Compensation.

Using ColorMunki for verification:

1) CM profile: http://tinyurl.com/4yqu4km

2) i1D2 profile: http://tinyurl.com/3kgq5od

 

Using i1D2+CCMX for verification:

1) CM profile: http://tinyurl.com/3jncfnc

2) i1D2 profile: http://tinyurl.com/3fkhqz8

 

On Sat, Sep 10, 2011 at 7:50 AM, tony22p <tony22p@xxxxxxxxxxx> wrote:

But Xun, to me this raises a question. If you had to raise the black point
did you then wind up being slightly out of calibration? In other words, was
the black point setting originally where the calibration software said it
needed to be?

 

From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of xun wang
Sent: Saturday, September 10, 2011 12:40 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Crushed shadow details

 

Never mind I see what I did wrong. All I had to do is to raise the black
point a bit to get all the shadow details.

On Fri, Sep 9, 2011 at 10:22 PM, xun wang <xun911@xxxxxxxxx> wrote:

Thanks that works!

 

I did some some further testing and comparison, and noticed that with
ArgyllCMS I still get less shadow details than the profile created using
X-rite's OEM software(ICC v2). Using photoshop's curve tool, the lowest
discernible shadow details using x-rite profile is 2. With ArgyllCMS profile
it's 4. I don't see any noticeable color casts in the shadows by either
profile.

I also get less gamut volume with the ArgyllCMS: 1,114,180 vs 1,087.920

 

Below is the DispcalGUI screenshot for the settings I used, please let me
know if there're anything I haven't optimized. Because I would really love
to use ArgyllCMS for my main calibration tool for its powerful features and
flexibilty. But for now the x-rite OEM software seems to give superior
result yet taking a fraction of the time.

 

DispcalGUI setting screen shot: http://tinyurl.com/3vw7o9y

 

I also ran "Very Profile", I'm not entirely sure but it also seems to agree
that the x-rite profile is oeverall slightly more accurate?

x-rite profile verification: http://tinyurl.com/44eptzd

argyllcms profile verification: http://tinyurl.com/4yqu4km

 

Any help and inputs are greatly appreciated!

 

Xun

 

On Fri, Sep 9, 2011 at 2:54 PM, Florian Höch <lists+argyllcms@xxxxxxxxx
<mailto:lists%2Bargyllcms@xxxxxxxxx> > wrote:

Am 09.09.2011 20:28, schrieb xun wang:

 

Is there anyway I could create a "single gamma + matrix" file for
Colormunki using the existing saved calculation data without running
through the "Calibreate & profile" process again? it's painfully slow
when I use "adaptive hires" + Black Drift Compensation for the Colormunki.

 

Yes, you can use the existing ColorMunki data to create a new profile from
it. (using the commandline tools, give the existing .ti3 as last argument to
colprof. Or if you use dispcalGUI, set the desired profile type, then in the
"Options" menu -> "Create profile from measurement data...", then select the
.ti3 file)

-- 
Florian Höch

 

 

 

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