ACES LUT's for use in a non-ACES environment November 2017
The LUT's attached below were developed by Geoff Boyle of CML and Nick Shaw of Anler Post with the cooperation of the NSC and Netherlands Film Academy.
The reason for these LUT's is to enable low budget and very fast paced productions to have the advantages of an ACES workflow whilst shooting with their "normal"kit.
The LUT's are designed to take the log output of many commonly used cameras and enable you to use a standard rec 709 monitor and reproduce the "look"of having gone through a complete ACES workflow. IE they contain the effect of the relevant IDT, RRT & ODT.
If you use these LUT's when shooting you should be able to use "standard"IDT's & ODT's in post with no LUT and get exactly what you saw when you were shooting.
We are currently working on versions of these LUT's that will load directly into the monitoring of the cameras that are capable of this. Currently you will need to use an external LUT box between the camera and the monitor. I have personally done this with an Odyssey and a Terradeck Bolt, we are testing and talking to manufacturers to establish what their systems need.
Working this way enables you to use a conventional film style workflow, ie no grading onset, no DIT, just a simple data transfer and backup:-)
It is easy using Prelight to generate this type of file incorporating a "look" if you follow this route you will need to generate 2 LUT's in Prelight, one incorporating the ACES "look"and one without. This is simply clicking 2 buttons withing Prelight.
There are two versions of these LUT's, one with normal contrast and one with contrast reduced to 0.85, this lower contrast is my personal choice.
These LUTs are designed only for use in LUT boxes or LUT capable monitors to preview the "base look" of ACES when shooting. They should not be used in post production. Use software which supports ACES directly.
Each LUT comes in two versions, designated EE or LL in the file name, folowing the convention used by the ARRI LUT Generator. Both versions are designed to achieve the same result, but you need to choose the appropriate one, depending on the way your LUT box works, or has been set up. EE means Extended range in and Extended range out, and is designed for LUT boxes which take the 64-940 SDI range (0-100%) and scale it to 0-1 before applying the LUT, then scale the result back to 64-940. LL means Legal range in and Legal range out, and is designed for LUT boxes which apply the LUT directly to the un-scaled SDI code values. A good double-check of whether you are using the correct version of the LUT is to overexpose an image and look at it through the LUT on a waveform. ACES ODTs roll off to 100%, so if you see "super-whites" in the image, or if the whites peak below 100%, it is likely that you are using the wrong version of the LUT.
The LUTs included in the set are:
PANASONIC_V-Log_V-Gamut_ACES_709_LL.vlt (for in camera use)
SONY_S-Log3_S-Gamut3Cine_ACES_709_MLUT.cube (for in camera use)
These LUTs are built from the CTL IDTs provided by the various manufacturers, as well as CTL transforms from A.M.P.A.S. This should not be taken as an endorsement by either the camera manufacturers or A.M.P.A.S. The LUTs are provided "as is" and you should test that they are suitable for your purposes. Neither CML nor Antler Post can be held responsible, legally or otherwise, for any damages or losses which may arise from their use.
The LUT's were created with both Prelight and Lattice. Prelight being a WISWYG system with Lattice being a more technical but contriollable approach.
They can be used in combination with manufacturer supplied ACES IDT CTLs, and the transform CTLs published by A.M.P.A.S. This should not be taken as an endorsement by A.M.P.A.S. of the CML / Antler CTL files.
Multiple CTL files can be combined in software such as Lattice, LightSpace or CTLrender to produce a transform which may then be saved as a LUT. The order of operations is important. The exposure adjustment operators should be used in a linear space, e.g. ACES 2065-1, and the contrast operator should be used in a logarithmic space, e.g. ACEScct.
The following example sequence of CTL files will produce a legal-to-legal LUT (i.e. one which operates on un-scaled SDI code values) for a Rec.709 / BT.1886 display. It is for an ALEXA LogC signal, reduces exposure by one stop, and contrast to 85%:
The legal to full conversion is applied at the start because the ALEXA IDT expects full range (i.e. with 0-1 representing 0-100% 'IRE') input. Some IDTs (e.g. those from Canon, Panasonic and Sony) expect legal range input (i.e. 0-1 represents the un-scaled 0-1023 SDI code values) in which case no input scaling operation is needed for a legal-to-legal LUT. They would however need a full to legal input scale for a full-to-full LUT.
These CTLs are provided "as is" and you should test that they are suitable for your purposes. Neither CML nor Antler Post can be held responsible, legally or otherwise, for any damages or losses which may arise from their use.