So, Yves, what chain of conversions will you be going through :
- From IT8 “RGB” to printer “RGB”?
First, do make sure the output of whatever Input RGB to Wolf IT8 is “good”?
Otherwise, you’ll be carrying inaccuracies down to the printer profile and
blaming errors on the printer profile. Work “modularily”.
/ Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On Behalf
Of Yves Gauvreau
Sent: Friday, March 18, 2022 5:38 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Prints to dark, how to fix this?
Tomorrow I'll do the following test, I'll use the Lab values of the Wolf IT8
target, and print them using the profile I made for this paper that give me
problem. From there we'll have data to work with and we'll see if I have
imaginary problems or not.
Yves
On 3/18/2022 4:25 PM, graxx@xxxxxxxxxxxx <mailto:graxx@xxxxxxxxxxxx> wrote:
Yves,
If you are convinced “it is the profile”, why not print a small chart with a
series of known color patches? That way, you could compare what the print gives
you relative to what you know the colors to be (Lab Input vs Lab Output).
You don’t say how much light is being reflected to your eyes from the print?
Compared to how your monitor is calibrated, Luminance wise? If you want to put
all the chances on your side, the amount of light reflected towards your eyes
from the print should not be too far off the amount of light emitted towards
your eyes by the monitor. You could use a simple photographic light meter to
compare the amount of light incident on your face from both the monitor and the
print, being illuminated by your LEDs.
Keep in mind that, having a high CRI is not a guarantee of anything.
Ultimately, your eyes tell the story. I assume the paper has no optical
brighteners.
In the “printing world”, the ISO-3664 standard provides a simple “viewing
conditions” description: if your monitor is calibrated, say, to 160 cd/m2 and
your viewing booth has an illuminance of 500 Lux, at the print level, then any
observer would be considered in a standardized viewing condition and could make
judgement of print vs monitor. Of course, to make this kind of comparison, it
is expected to be carried at a D50 level. If your monitor is calibrated to D65
and your LEDs don’t provide the same chromaticities, then you’re one strike
down. And even if both give you the same D50 chromaticities, it’s possible that
you may not still observe a satisfactory match. Colorimetry is a bitch.
How does the match look, a picture of the Munsell ColorChecker chart viewed on
your monitor vs a physical chart viewed under your LED?
Any other suggestions?
/ Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <mailto:argyllcms-bounce@xxxxxxxxxxxxx>
<mailto:argyllcms-bounce@xxxxxxxxxxxxx> <argyllcms-bounce@xxxxxxxxxxxxx> On
Behalf Of Yves Gauvreau
Sent: Friday, March 18, 2022 4:09 PM
To: argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
Subject: [argyllcms] Re: Prints to dark, how to fix this?
On 3/18/2022 12:01 PM, Alan Goldhammer (agoldhammer) wrote:
This video from Andrew Rodney is useful:
https://www.youtube.com/watch?v=iS6sjZmxjY4 ;
What happens if you print a standardized image from your printer?
I forgot to try this.
Are the colors and brightness level correct?
I use Photoshop to soft proof the image before printing and I make a copy
without soft proofing active and I try to match them as best as I can. Whatever
I do here, the print is much darker, it's unacceptable to me when I have to
tweak my image before printing, that's guess work.
What is the light source you are viewing the "too dark images" under? Perhaps
your viewing light source is not bright enough. Remember, prints are
reflective; the monitor is transmissive. Personally, I think your screen
brightness is very low. Are you using it in a dark room?
I use a high CRI > 95 5000K 800 Lumens Led bulb to view my prints and about 2
feet above the print. My screen is a BenQ SW270C that I hardware calibrated
with my I1 Pro 2 and on top of that I made another profile with DisplayCal and
I get pretty good results, nothing above 1.0 DE2000 and I view my screen in
about 30 lux of light measured at 2 feet from my screen.
I'm practically certain it's the profile but I don't know how to test this
hypothesis and if I'm right, I don't know either how to correct it so I don't
have to tweak my image all the time, I'm not convinced at all that this is the
way to go.
Yves
