I heard there was some discussion on a 3DLUT standard format, so here is an update on the Common LUT Format (also sometimes known as the Academy/ASC LUT format, or Academy LUT or ASC LUT, really all of the same thing, not ASC LUT II.
The ASC-CDL was a separate development although it included many of the same people )
A main goal of the committee was to provide a LUT format that could handle metadata in a fashion consistent with current practices. XML was chosen as the format to carry this metadata. This allows further information to be attached to LUTs in a consistent fashion.
<ProcessList xmlns="urn:NATAS:ASC:LUT:v1.0" id="LUT12Jul09" name="Prod
<Description> Convert to rec709 from Slog with 3D LUT </
<Description> made for Prod XYZ </Description>
<InputDescriptor> Sony F23 Slog </InputDescriptor>
<OutputDescriptor> Sony BVM CRT </OutputDescriptor>
<LUT3D id="LUT120709" name="Slog convert" interpolation="trilinear"
inBitDepth="10i" outBitDepth="10i" >
<Description> converted to rec709 primaries with D65 white </
<Array dim="17 17 17 3">
0 0 0
1 1 1
3 3 3
5 5 5
***lots of other lines*************
1023 1023 1023
One of the goals of the committee to improve adoption was to have a reference implementation to speed adoption. There are several implementation efforts underway, and there has been progress on creating an XML reader for the format. But the effort is largely volunteer, so it is taking a while to get results.
The specification is contained in :
"A Common LUT Format for Look-Up Tables", version 1.01, May 11, 2008
Ed: Jim Houston, Common LUT Format Committee, Academy of Motion Pictures Arts and Sciences
I have put this up on a temporary basis at
There have been some implementation notes that may require some revisions, but these have not yet been incorporated.
Thanks for the interest in this format. We still have regular problems with LUTs on a frequent basis many of which can be traced to lack of communication of what is in the LUT. This format was designed to help, but faces a bit of a chicken and egg problem as vendors are waiting for others to use it or request it, and users don't have it available in their most common tools so they can see how it might help.
>Just in time for this discussion of 3D LUT standardization comes the following message from David >>Reisner who is Secretary, ASC Technology Committee and DI subcommittees.
All things Color for Film and Digital Cinema
Hi everyone:Just in time for this discussion of 3D LUT standardization comes the following message from David Reisner who is Secretary, ASC Technology Committee and DI subcommittees.
To get download instructions, send an e-mail to email@example.com : Notice that this is a DIFFERENT ADDRESS than you may have used before.
Tell your friends.
Secretary, ASC Technology Committee and DI subcommittee
>>Thanks Dan. I'd just never heard it referred to as the "ASC" LUT standard.A lot of the same people were involved both the ASC CDL and the Academy LUT, but I just don't want to step on any toes by not crediting the proper overseeing organization.
Note:I was quoting Robert Monihan
I too have the LUT specification.
If anyone wants it, drop me an email.
Shouldn't we post it here on CML?
Chief Technology Officer
Band Pro Film & Digital
Dan Mulligan wrote:>>Bob Currier : Dan, can you expand on this? I'm aware of the ASC CDL and the Academy LUT standard, I too have the LUT specification.
Bob Currier : Dan, can you expand on this? I'm aware of the ASC CDL and the Academy LUT standard,
April 26 2007 : This process needs to be automated all through the pipeline,” Stump said. “I propose the ASC LUT — a standardization of the syntax in which LUTs are shipped from one machine to another. [Currently,] none of them have the same header information and syntax.”
The ASC LUT standard quite rightly evolved into the ASC CDL and Academy LUT we now have, the LUT came out of the same early discussions and was used, as I saw it, to show an evolving idea.
A Common File Format for Look-Up Tables by Jim Houston from April 2008 with AMPAS and the ASC technical committee also addresses this common standard for LUTs.
The goal is to improve the pipeline by enabling LUTs to be used in different technologies while maintaining a consistent meaning
Director of photography David Stump, co-chair of the ASC's metadata subcommittee, said that he has started to introduce this topic to various manufacturers, "It's all in the name of open source," Stump said. "The more people embrace open-source technology, the easier it is to do the work."
Of course, you can use the Light Illusion 3D LUT Builder to convert between different LUT formats, including gamma and colour space ...
This means Geoff can stick to Iridas as a working environment, and then simply convert the LUT to the post house's required format.Yes, yes, I obviously have an interest in this software ... Steve Shaw
>>I am sure you must have run into some of them. I know Wolfgang and studied at Derby ?
Geoff Boyle FBKS
US +1 818 574-6134
UK +44 (0) 20 7193 3546
mobile: +44 (0)7831 562877
>ASC LUT II standard
Dan, can you expand on this?
I'm aware of the ASC CDL and the Academy LUT standard, having sat in meetings on both, but not sure what you're referring to here.
I know Dave uses LUTs extensively, but I haven't seen anything published on a unique LUT format.
Bob Currier 3349 Cahuenga Blvd West, Suite 3
CTO/Partner Los Angeles, CA 90068
Gamma & Density Co. +1 323 436-7593
This subject has been a thorny issue now for quite a while. As I’m sure you are aware Dave Stump ASC developed the ASC LUT II standard that has been adopted now for a lot of post workflows to create that standard, in fact it’s something that’s been developed for a long time and not such a new idea. Certainly white papers have been written on the subject, which I'll gladly post (with permission) on our client forum.
In fact in 2007 I had written an article on this subject for HD Magazine that’s still top of their downloads list, so this is not a new subject at all. The 3D LUT standard has been here for at least two years now the next step is to try and get a standard for digital itself and prevent all the digital banter that’s floating around.
3D LUTs, workflows, standard practices etc need to be adopted, I feel, and soon. Film language is part of everyone’s DNA it’s now time to understand a new language, and I can't believe it’s taking us so long to do it?
Dan Mulligan's two pence worth!
Elstree Studios, UK
Geoff Boyle wrote:>Yeah well you know, I’m just a simple bear.
>Geoff Boyle just repeated ("we know 1D LUTs can't do saturation"), which result from a simplistic >>application of 1D LUTs and drawing conclusions from that
Yeah well you know, I’m just a simple bear.
I deal with real world situations and real world problems.
Geoff Boyle FBKS
US +1 818 574-6134
UK +44 (0) 20 7193 3546
mobile: +44 (0)7831 562877
>>Sorry to say, not something I'm really interested in wasting time on.Steve, no where have I suggested that you spend/waste more time or change your business around making 3D LUTs. I have just pointed out some inconsistencies and misconceptions regarding 3D LUTs and 1D LUTs held by many, that for e.g., Geoff Boyle just repeated ("we know 1D LUTs can't do saturation"), which result from a simplistic application of 1D LUTs and drawing conclusions from that, while not exploring various input/output mixtures in which 1D LUTs can be configured to approximate the response of a 3D LUT.
Geoff Boyle wrote:>>Well Bill when I grade something, produce a "look" I have a choice of a huge variety of formats to store it in >>depending on which system I'm going to finish in. I was on a committee with a bunch, to create a standard file format for 3DLUTs. It was pretty good!
Rupert I'll call them Smurfs if someone will standardise them.
Hell! I'll call them any bloody thing that anyone who produces a standard wants to call them!
class="style17 style20" >> ,,,,,,I know that I'm a voice in the wilderness, after at least 10 years of asking for this I'm no closer.,,,,,
Standardization and coherence are not in the best interest of the post-production and equipment-manufacturer profit model
David Perrault, CSC
GeoffWould it not be an idea to keep LUTs for engineering purposes and
+44 7787 554801
>>Could you explain what you mean by "standardizing" 3D luts?Well Bill when I grade something, produce a "look" I have a choice of a huge variety of formats to store it in depending on which system I'm going to finish in.
If we could just get a standardised LUT format, this is for creative LUT's not engineering ones, then life would be a lot simpler.
Then instead of me getting log stills files to grade and then email back reference pics that the colourist tries to get close to I can email him a "look" file that he can load and know the he's at least staring close to the original idea.
Of course I know that I'm a voice in the wilderness, after at least 10 years of asking for this I'm no closer.
I know the monitors won't be spot on, I know that there will be variations due to room conditions, I don't care! These are creative LUT's, guides as to the look and not precise engineering ones.
The problem is that all of this is dealt with by engineers who can't cope with the imprecision we want!Geoff Boyle FBKS
Ideally we should all use the ICC color profile format (www.color.org)
It can handle 1D, 3D LUTs and much more (metadata, etc)
© copyright CML all rights reserved