I made a small FAQ and package based on Argyll_V2.3.1 with examples to create so called "Well Behaved" Matrix Input Profile for camera/scanner that is specially useful for negatives invert and processing. "Well Behaved" input profile with D50 white point behave and respond in same way as normal working profile, so you can pick film base, invert and pick WB directly inside original unmodified data in linear gamma.
Dropbox links not allowed here so you can find package here in original thread https://liftgammagain.com/forum/ind...per-cineon-inversion.13714/page-6#post-167174
Based on these articles:
Some background info:
ArgyllCMS folder form ZIP archive should be placed on Desktop
Files and folders names should have no spaces
Don't use TIFF compression. Argyll can't read compressed TIFFs
is a scanned IT8.7 chart image.
Reference_File.txt (or .cie)
is a reference file for IT8.7 chart with measurements provided by chart manufacturer.
is a grid guide file for patches autodetection. It is provided by Argyll for all supported color charts. You can find it in Argyll_VX.X.X/ref folder downloaded from here https://argyllcms.com/
. I use it8.cht file which was extracted from RoughProfiler because its grid better optimized and modified for IT8.7 chart that i use.
is a file generated for visual inspection only. It helps to check if all patches where autodetected in correct places.
is a file generated by scanin that contains measured data. It is used by colprof to generate ICC profile.
Compensate for perspective distortion
different options to adjust the look of diag.tif
Gamma of Test Chart. It helps to improve patches autodetection
Internal Profile Name
Profile default intent Perceptual
Profile quality High
Profile type Matrix only
Auto adjusts Exposure of Test Chart, so white patch became 100% white
Prepare your Test Chart
Based on this tutorial https://ninedegreesbelow.com/photog...ra-profile.html#raw-process-set-white-balance
Open your Reference_File.txt in text editor and search for the most neutral LAB_A LAB_B gray patch that have LAB_L value at least 50.00. In most cases it is somewhere between GS1 to GS8 patches.
In Raw editor pick White Balance based on this patch and export Test_Chart.tif in Linear gamma with disabled color management.
Generate .ti3 data file and diag.tif file. Type this code in Terminal:
~/Desktop/ArgyllCMS/scanin -v -dipnoa -G1.0 ~/Desktop/ArgyllCMS/Test_Chart.tif ~/Desktop/ArgyllCMS/it8.cht ~/Desktop/ArgyllCMS/Reference_File.txt ~/Desktop/ArgyllCMS/diag.tif
Based on this tutorial https://ninedegreesbelow.com/photog...rofile.html#add-D50-white-black-color-patches
Open Test_Chart.ti3 in text editor and add additional lines with perfect synthetic D50 white and black color patches. Also NUMBER_OF_SETS should be changed from 288 to 290. So it should look like this:
00W 96.4200 100.000 82.4910 100.000 100.000 100.000 0.000000 0.000000 0.000000
00B 0.000000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.000000 0.000000
For matrix profiles ArgyllCMS automatically pick WB from whitest and darkest patches in the chart, but in most cases whitest patch is very far from perfect white and also have huge tint compare to other darker patches. So this "hack" helps to bypass White Balance shift of IT8.7 target. Guess it should be used only for simplest matix-based profiles that don't allow to fine tune every WB patch separately. Also perfect D50 white point makes input profile behave and respond in same way as normal working profile, so you can pick film base, invert and pick WB directly inside original unmodified data in linear gamma.
Note that simple matrix-based profile produce decent calibration results only with high CRI light sources. If your light source have low CRI or use RGB LEDs with non uniform peaks, it usually needs way more complex correction than simple matrix input. Guess in this situation it is somehow possible to create additional secondary correction LUT that will adjust colors in complex way.
Create Input Matrix ICC profile. Type this code in Terminal:
~/Desktop/ArgyllCMS/colprof -v -D"Profile Name" -Zp -qh -am -u ~/Desktop/ArgyllCMS/Test_Chart