Sunday, July 07, 2013

Iliah Borg's MakeInputICC: A camera profiler wrapper for the Argyll engine

Nutshell summary: Iliah Borg has assimilated Argyll into a user-friendly wrapper for making input profiles; this Borged wrapper assists quality assessment by graphing the profile's curves for each of r, g and b.

Download links at the bottom of this post!

Argyll is Graeme Gill's highly respected open source profiling engine. As we all know, open source like Linux is often quite useful, but a bit —errm, awkward. Well, in the case of Argyll, very useful and very awkward. Camera profiling is already sufficiently frustrating without the need for long command-line incantations.

Sometimes, geeks do realize the failings of other geeks and write graphical interfaces. And we regularly see wrappers emerge which combine the know-how of a specialist's use of profiling workflows with Argyll's engine. Such is the case of MakeInputICC which wraps Argyll's nightmarish command line options into a menu system that a mere Ph.D might understand, while providing some feedback on profile quality.

One question which comes to mind of course is: "But where does the input data come from"? Traditionally, input profilers are interpolation engines which need two input files: A reference file for the target, which is provided here in spectral form for some industry standards; and a very clean test shot corresponding of said target. 

However, MakeInputICC expects to ingest a pre-digested CGATS file of rgb values extracted from the target. The necessary file can be supplied by Alex Tutubalin and Iliah Borg's Rawdigger which is not open source, or by any other method known to ColorGeeks;  Danny Pascale's PatchTool is one very convenient commercial utility which can help do this job, generating a CGATS file after reading in a target image Tiff generated by one's favorite Raw converter. 

I am not going to comment on profile quality, as all the authors of camera profiling software are by now personal acquaintances. However the beginner should be warned that camera profiling is something of a black art and is highly dependent on the abilities of the photographer.

But even if camera profiling is a black art, it remains a necessary evil: ICC profiles are essential for the use of any of the open-source dcraw descendants. They are also a requisite for any serious art reproduction work with an ICC-compliant commercial converter such as Capture One or Iridient's Raw Developer. In fact some color geeks consider it very unfortunate that Adobe's ACR is not compatible with ICC profiles.

Among profiling software, MakeInputICC has the advantage of creating license-free profiles; it  should find an audience among specialist photographers who may have been frightened of Argyll's steep learning curve. Said exigent experts will no doubt run their own tests in their own lighting and working conditions, with their own Raw converters, and compare the output of Argyll to those profiles created by boutique products such as Basicolor Input. 

I like Iliah's software because it is simple to use and provides instant feedback on whether a profile is clean or not.  On the other hand, the tabular output is less useful to humans than a target image would be; it seems to me that  the author might as well integrate a patch reader and target display into his software. Or maybe some other geek will revise this geek's work too — accretion seems to be the constructive process by which the open source bazaar extends its labyrinthine cathedral.

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