LUT's that emulate the ACES workflow

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(Geoff Boyle) #1

This is a new page at CML reproduced in its entirety, hopefully the links will work!

ACES LUT’s for use in a non-ACES environment
The LUT’s attached below were developed by Geoff Boyle of CML and Nick Shaw of Antler 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 very simple data transfer and backup :slight_smile:

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.

ACES 1.0.3 LUTs for On-Set Preview normal contrast

ACES 1.0.3 LUTs for On-Set Preview lower contrast

from CML in association with Antler Post

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.

These CTLs are some custom ones created when building the CML / Antler ACES LUTs. They are provided to help you if you wish to make your own ACES LUTs within Lattice, they are not needed for Prelight.

The CTLs included in the set are:








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.

LUT's that emulate the ACES workflow (repost)
(Nick Shaw) #2

I am compiling a table of which version of the LUTs I have confirmed is appropriate for various LUT devices.

Here is my initial list:

I will update the file at the same link as I add more devices.

(Lewis Saunders) #3

I’m happy to see these since the tipping point of whether a job uses ACES can easily be which LUT is used in the monitors on-set, and in the offline media that’s created there.

The EE Alexa and Red LUTs match the native ACES implementation in Flame 2018.3, comparing R3D and Arriraw files debayered to ACES directly and the same files going via Log3G10 or LogC.

I’m curious about the video levels scaling that’s needed for Panasonic and Sony - I don’t get a match unless I apply an extra full-to-legal scale as mentioned at the end of Geoff’s post. Is it documented somewhere that these IDTs expect legal range input? In the Slog2 IDT there is clearly 64-940 maths, but for Slog3 the Sony PDF seems to imply full range.

If I debayer an F65 MXF to ACES directly using the Sony RAW controls and then apply RRT+ODT, it does not match the same file debayered to Slog3/SGamutCine followed by SONY_S-Log3_S-Gamut3Cine_ACES_709_EE.cube. To match that .cube I have to debayer to SLog, apply a full-to-legal scale, then use the IDT, RRT+ODT. This makes me wonder whether the SLog3 IDT does in fact expect legal range input… I would expect Sony’s debayer-directly-to-ACES result to match if that was the case?

(Nick Shaw) #4

If working in post software, you would indeed need to add additional range scaling for Sony, Panasonic and Canon. These LUTs are designed to work in hardware LUT boxes, not post software, as the range handling for those manufacturers is different there.

Yes, indeed it does. It’s the same as S-Log2, but the range scaling is not explicit. In post software the raw decodes effectively to legal range, i.e. matches the unscaled S-Log3 SDI code values output by the camera.

(Geoff Boyle) #5

I’ve added in camera LUTs for Sony & Varicam here


Geoff Boyle NSC

(Geoff Boyle) #6

I’ve just updated the links in the original post to include a package of LUTs with a lower contrast than normal. 0.85 which is my personal favourite.

I’ve also updated the original package to correct some errors in the Canon 2020 varieties, so many possibilities, so little time :slight_smile:


Geoff Boyle NSC

(Nick Shaw) #7

The 0.85 contrast versions can be matched in Resolve or Baselight by applying 0.85 contrast, with the default pivot setting of 445 (or 0.435) in ACEScct. It can also be replicated with an ASC-CDL adjustment with Slope: 0.85 and Offset: 0.06525.

(Nick Shaw) #8

I have tested a Teradek Bolt 3000 and an AJA LUT box today and added them to the list:

(Nick Shaw) #9

And as a bonus freebie, here is a simple drag-and-drop Automator app for OS X which will convert a 33^3 LUT to 17^3 for LUT devices which require that:

It’s not a robust universal converter, so no guarantees it will work with other LUTs, but it works with my ACES sets.

(Nick Shaw) #10

The table is updated again to add IS Mini and ATOMOS. I am working on getting other devices to test. There is also a correction to the entry for FSI monitors, due to an earlier misunderstanding over terminology.