ColorChecker.cht pulls up a target that fits perfect over my chart -
all the same colors, same rows, same thing so far as I can tell. It is
the bottom row, of 4 rows (rows are A, B, C, and D), that had the gray
scale - but in the drop down menu in the process tab, it has A1…D6
as the only possible selection - as if it is saying every square in
the whole ColorChecker is suitable for the grey ramp - Im guessing
that is wrong. My guess is D1…D6 should be the the correct
selection, but no such beast in the box.
@troyatlarge I had the same problem with the ColorChecker SG. In the darktable development version we changed the code to automatically detect the gray patches instead of relying a corect grey ramp definiton in the cht file.
So you either have to install the development version to get the latest darktable-chart to create a profile or wait for the release of darktable 2.6 which is normally Christmas!
Ahh - thank you! You mention “…relying a correct grey ramp
definition in the cht”. Exactly what part of the cht file defines that
grey ramp? For example, mine reads, in part;
BOXES 25
F _ _ 10.0 9.75 321.25 9.75 321.26 217 10.0 217
D ALL ALL _ _ 330 228 0 0 0 0
Y 1 6 A D 46.0 46.0 12.0 11.5 52.5 52.5
Is part of this pointing to the grey ramp, and if so - which part? I
am assuming here that part of this is building the drop down box
selection in the process tab, and in this case, is doin g so
incorrectly - like it needs to be switched to Y 16 D D or some such
thing. Am I way off base here?
No it does not look like that chart… more like the right half of that chart. It looks more like the chart seen here: ColorChecker - Wikipedia
To be exact, the chart shown is using the colors listed on the wiki page covering that color chart as seen here: ColorChecker - Wikipedia
What we did was print out, on a high quality printer up to the task, these colors on a like shaped chart and then ran a spectral analysis on the printed colors thereby being able to calculate the DE of the colors, many of which are like 0.3, 0.5, etc., save for the white which had a DE of 3.4. I now want to test the thing for issues to see if one could reasonably use it, or if I must upload its individual Lab coordinates in its own cie file and expected XYZ in a cht file.
However, at this point I feel something else is going wrong before I even get that far - the cht file, or whatever file it is that controls it, should not have the gray ramp choice as all the rows from A1 to D6, but instead should only include D1 to D6, unless I am grossly mistaken somewhere.
Andreas, can you please elaborate a bit more about differences between shooting scene specific profile and general profile? How should I shoot ColorChecker Passport for scene specific lightning conditions? Are there any differences?
I find scene specific profiles very useful especially for mixed lightning fluorescent and daylight or just for artificial lightning. Market quality fluorescent bulbs and LEDs have poor spectrum and can give specific tints or color shifts.
Thank you for the article anyway! It is a great help!
Hi, I appreciate this article, as I am a photographer who uses ColorChecker to make camera profiles to use in Lightroom, but I am exploring leaving Lightroom but still want to have my cameras profiled.
I already have darktable installed and use it at a basic level, so I thought I can do this.
But it appears to be beyond me to get darktable-chart running. I am using MacOS Mojave. I eventually found a reference (not in this article) that I have to install developer version of darktable to get a working copy of darktable-chart. If this is the instruction for how to install it, link, then it is too computer-savvy-guy for me. I am more photography guy and less computer guy. I am trying to do it, but every step needs me to do things I have never done and learn things I don’t know. My computer does not even allow me to modify files like macports.conf and variants.conf, as required in the linked page.
Did I miss something, or is it really this hard to get a copy of darktable-chart and run it on my computer?
P.S. talking about an easier way, I already have the camera profiles (in .dcp format) that I made with the ColorChecker process using Macbeth target. Is there a way for me to convert these into the format needed by Darktable? Then I don’t need to do the darktable-chart process.
I should just run away and play now, but I do want to say that it might as well have been an Easter Egg as far as I was concerned. There is no way I would have found that by myself. I searched my hard drive for “darktable-chart” and found nothing. Even now, I cannot find in Finder the folder that you reference, “/Applications/darktable.app/Contents/MacOS/”. Why can’t I find the executable for darktable-chart, even though I am now running it with your command?
Might I suggest @asn that you add to the OP a few words on how to start darktable-chart, please? And also the Darktable User Manual p219, starting darktable-chart is taken as a given when, to me, it is worth mentioning how one does that.
