Ok, so I have found a part of the answer…
Gretag_Macbeth use some files for “Light sources” (ProfileMaker5 Measure Tool uses these) which look very like an IT8.7 target file.
The data is spectral data 380nm to 730nm (as measured by Eye-One Pro). These files can be found (PM4 or PM5 users - Windows OS) in C:\Program Files\GretagMacbeth\ProfileMaker Professional 5.0.5\Measurement Files\Light Sources.
PM5 accepts multiple “sets”, but ColorThinkPro (v3.0) will only read the first set (it appears to ignore the others, which is fine for me).
So I have constructed single illuminant files for the light sources that I needed by:
1 Measuring the light source using Eye-One share and saving the data as a “.cxf” file
2 Using Excel to open the “.cxf” file and copying the spectral intensity values
3 Pasting (using “paste_special/transpose”) into a text file (in Excel).
4 Saving the file from Excel as text (".txt")
5 Opening the text file with Notepad (text editor)
6 Copy/paste into the “template” text file with a similar format to the GretagMacbeth “Light Source” files.
The reason that I dont do the whole thing in Excel is because Excel (not very helpfully) when reading the text file strips out the Quotation ( " ")marks which appear to be an integral part of the CGATS spec.
“MEASUREMENT_SOURCE…”, “SAMPLEID…” and “1 10D_Flash…” should be all on a single line (HTML will put phantom line breaks in when you read this).
A workable file format seems to be as follows:
CREATED “02/03/2006” # Time: 18:10
INSTRUMENTATION “Eye-One Pro”
MEASUREMENT_SOURCE “Illumination=Unknown ObserverAngle=Unknown WhiteBase=Abs Filter=Unknown”
SampleID SAMPLE_NAME nm380 nm390 nm400 nm410 nm420 nm430 nm440 nm450 nm460 nm470 nm480 nm490 nm500 nm510 nm520 nm530 nm540 nm550 nm560 nm570 nm580 nm590 nm600 nm610 nm620 nm630 nm640 nm650 nm660 nm670 nm680 nm690 nm700 nm710 nm720 nm730
1 10D_Flash 0.000929975 -0.0235814 0.147943 0.421343 0.536534 0.604945 0.660189 0.684064 0.766526 0.750329 0.751998 0.729285 0.6534 0.593494 0.617933 0.636181 0.634857 0.608826 0.586445 0.544186 0.567587 0.591566 0.538842 0.555021 0.504815 0.48403 0.442343 0.546393 0.547209 0.431345 0.384908 0.462377 0.465281 0.580814 0.328768 0.351967
What I don’t yet know - ("…part of the answer…") is what to do about scaling the values to avoid arithmetic errors. My data above corresponds to a light level (reported by Eye-one Share) of 43lux. Gretag Macbeth files appear to be 2,500 to 7,000 lux.
I also found that the Argyll site (LCMS) referred to, but did not define, a CGATS (style) format text file.
CGATS17-2005 (ANSI spec) hints at illumination capability (in the context of a user defined field) but does not define this particular format either in text or XML.