Have you compared the “extremes” of each print?
To my knowledge, the DeltaEcube are a common way of expressing gamut size
(volume).
So what could account for the difference?
You need to compare the cyan, magenta, yellow, black,m red, green and blue of
both prints.
Then, you’ll know because the gamut size is determined by the extent of those
CMYKRGB Lab colors.
/ Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On Behalf
Of David Lewis
Sent: Friday, June 28, 2019 5:08 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Vastly different Gamut for similar process
As a follow up to this email - we went back and repeated the test on the same
two prints.
Sheet 1 Test 1
Total volume of gamut is 657672.991146 cubic colorspace units
Sheet 1 Test 2
Total volume of gamut is 222273.910551 cubic colorspace units
Sheet 2 Test 1
Total volume of gamut is 235795.488083 cubic colorspace units
Sheet 2 Test 2
Total volume of gamut is 254107.037880 cubic colorspace units
What might have happened in the first test that it is so out of whack, and how
would a person know this in the normal course of measuring?
Are these second round tests within what could be considered a similar result
basis? In other words is 31,834 cubic colorspace units a minimal value? (In
which case why does this number have 6 decimal places)
Lastly - I am still very interested in opinions about my original questions
below...
David Lewis
On Fri, Jun 28, 2019 at 3:15 PM David Lewis <david@xxxxxxxxxxxxxx
<mailto:david@xxxxxxxxxxxxxx> > wrote:
Hi,
I created a set of patches that covered a letter size sheet for a printing
process, I produced two different prints from this patch TIFF file and they
visually look quite identical. I then read them using a new I1Pro....
Using these commands:
chartread Color-Print
colprof -v -D"Color-Print" -qm -S AdobeRGB1998.icc -cmt -dpp Color-Print
iccgamut -v -w Color-Print.icm >Color-Print-iccgamut.log
I get two VERY different gamut sizes...
Total volume of gamut is 657672.991146 cubic colorspace units
Total volume of gamut is 235795.488083 cubic colorspace units
I was expecting these to be very similar and to then represent a number that I
could compare against other prints as a quick way of determining "the potential
amount of color range difference" between two or more prints.
Am I correct that "cubic colorspace units" represents a volume of visible
colors such that a larger number represents more visible color potential?
What might cause these two tests to end with such vastly different results, and
where do I go looking for that cause?
Here is the ti2 header info...
CTI2
DESCRIPTOR "Argyll Calibration Target chart information 2"
ORIGINATOR "Argyll printtarg"
CREATED "Tue May 21 13:22:24 2019"
TARGET_INSTRUMENT "GretagMacbeth i1 Pro"
COMP_GREY_STEPS "128"
APPROX_WHITE_POINT "95.106486 100.000000 108.844025"
COLOR_REP "iRGB"
PAPER_SIZE "215.9x279.4"
RANDOM_START "48"
STEPS_IN_PASS "27"
PASSES_IN_STRIPS2 "27,4"
STRIP_INDEX_PATTERN "A-Z, A-Z"
PATCH_INDEX_PATTERN "0-9,@-9,@-9;1-999"
INDEX_ORDER "STRIP_THEN_PATCH"
NUMBER_OF_FIELDS 8
BEGIN_DATA_FORMAT
SAMPLE_ID SAMPLE_LOC RGB_R RGB_G RGB_B XYZ_X XYZ_Y XYZ_Z
END_DATA_FORMAT
NUMBER_OF_SETS 837
BEGIN_DATA
Here is the gamut header info
Header:
size = 497748 bytes
CMM = 'argl'
Version = 2.2.0
Device Class = Output
Color Space = RGB
Conn. Space = Lab
Date, Time = 28 Jun 2019, 14:44:39
Platform = Microsoft
Flags = Not Embedded Profile, Use anywhere
Dev. Mnfctr. = 0x0
Dev. Model = 0x0
Dev. Attrbts = Reflective, Glossy, Positive, Color
Rndrng Intnt = Relative Colorimetric
Illuminant = 0.96420288, 1.00000000, 0.82490540 [Lab 100.000000,
0.000000, 0.000000]
Creator = 'argl'
Total volume of gamut is 235795.488083 cubic colorspace units
vs
Header:
size = 497748 bytes
CMM = 'argl'
Version = 2.2.0
Device Class = Output
Color Space = RGB
Conn. Space = Lab
Date, Time = 28 Jun 2019, 14:11:50
Platform = Microsoft
Flags = Not Embedded Profile, Use anywhere
Dev. Mnfctr. = 0x0
Dev. Model = 0x0
Dev. Attrbts = Reflective, Glossy, Positive, Color
Rndrng Intnt = Relative Colorimetric
Illuminant = 0.96420288, 1.00000000, 0.82490540 [Lab 100.000000,
0.000000, 0.000000]
Creator = 'argl'
Total volume of gamut is 657672.991146 cubic colorspace units
