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I use ACES because I don't trust post....

Geoff Boyle
 

OK, a provocative title for my first post of the year.


It was incomplete and should have said...I use ACES because I don't trust post guys I don't know. Just like I don't trust gaffers, operators, grips, AC's who I don't know.

I've been experimenting a lot over the last few weeks/months with generating LUT's that are meant to help the shoot, not to dominate post or impose a "look" onto the final film but to give a level of control and predictability to images onset.

The thing is that "technical LUT's" do a great job in the hands of people I know and trust but more and more we are having to work with people and workflows that we don't know and trust and when things go wrong it's inevitably the fault of the person not in the room.

This is where ACES comes in to play, it gives us a fixed, international , independent reference. Just take the rushes and apply the Image Transform (IDT) and the Output Transform (ODT) and we can see what we shot without any outside help or interference. If with a standard IDT and ODT the image looks OK then the rushes are OK and anything wrong is further down the chain.

That's it, well for the Cinematographer anyway, there are other advantages for producers but this is a cinematography rant!

Now the problem with this is that we don't have an ACES onset workflow established, Oh there are all kinds of ways that with DIT's and shedloads of money we can do anything but I want something very very simple.
What we need are very simple LUT's to use onset (via LUT boxes or wireless links that will accept LUT's or via monitors that accept LUT's) that will show us on a standard 709 onset monitor what the image will look like after going through the ACES post pipeline.

Thanks to Prelight from Filmlight this is now easy to do. I've generated LUT's for Alexa, Canon, Panasonic & Sony cameras that integrate the ACES pipeline and can be used during a shoot in a very simple way. I've also generated for Alexa and Canon LUT's that incorporate the ACES pipeline with a reduction in contrast to 0.85 because that's how I like to see my rushes!

I've generated these LUT's from both captured footage and live camera input. In the latter case it's possible to add a "look" to the output as well.
I'm testing these with the NSC at the moment and we'll be going live with all of this on the 24th of January and after that I may well post some of these LUT's to the CML website. That is after they have been tested and torn apart by a lot of Cinematographers and DIT's!!


Cheers
Geoff Boyle
Cinematographer
EU Based
www.gboyle.co.uk
+31 (0) 637 155 076

Nick Shaw
 

On 1 Jan 2018, at 08:49, Geoff Boyle <geoff@...> wrote:

I've also generated for Alexa and Canon LUT's that incorporate the ACES pipeline with a reduction in contrast to 0.85 because that's how I like to see my rushes!

Baking ACES into LUTs for on set use is definitely a good idea. I've made similar LUTs myself in the past, and posted on ACES Central how to create them.

One thing to be aware of is that different LUT boxes apply LUTs in different ways with respect to the range of the data. Some devices (such as the FSI BoxIO and the Convergent Design Odyssey, both of which I consulted on, and advised them to make it work this way) allow you to choose the range that the LUT is applied in. But others are locked to one particular approach. Always test, to make sure the LUT you have created works in the way you expect with the LUT box you are using. I have suggested to Filmlight that they add range options (which exist almost everywhere else in Baselight) to the LUT export from Prelight. But I don't think it is there in the current version.

If the contrast adjustment is baked into a LUT it should be the same in all implementations, but it is worth noting that "contrast" is not a standard operation which is guaranteed to work the same way in all systems. It is also necessary to specify the pivot point, and whether it is applied in ACEScc or ACEScct, as the results will differ. I would suggest that ACEScct should now be the default (although that is not compatible with ACESproxy, as ACEScc is). It may also be worth converting the 0.85 contrast you use to ASC CDL, which means it is defined in a standard platform independent way.

Geoff, if you want to contact me off list, I would be happy to work with you on creating the set of LUTs you propose publishing.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)20 8892 3377
+44 (0)7778 217 555

Geoff Boyle
 

I think they’ve listened to you as they seem to be in my current Beta of 5.

I’ll certainly contact you off list as this seems like something that could be very useful.

I’m working on the basis that we’ll be using act in all cases.

The reduced contrast is really just a personal obsession! I want to get bog standard ones out first.

Cheers
Geoff Boyle
Cinematographer
EU Based
www.gboyle.co.uk
+31 (0) 637 155 076



On 2 Jan 2018, at 13:23, Nick Shaw <nick@...> wrote:

I have suggested to Filmlight that they add range options 

Steve Shaw
 

Hi Geoff - I'm happy to help with any LUT generation...
Feel free to mail me directly with needs, etc.

Steve