Indie DI with Color, questions..
by Rick Turners
on
Aug 12, 2009 at 11:05:48 pm
Anyone here have experience doing a DI with color?
I'm not too familiar with the process of doing a film out and have a few questions..
Editorial brings in a DPX conform, color grade is done in Color with the appropriate LUT.. However your only available monitoring is say, a 24" FSI HD monitor or something like it.
Obviously its not going to be perfect using a small monitor to grade something that will be screened in a theater.
Do you schedule a once-over session with a 2k projector at the DI facility before going out to film?
Also I'm guessing the calibration will not match perfectly from home to facility... how is this dealt with?
Re: Indie DI with Color, questions.. by Patrick Inhofer on Aug 13, 2009 at 6:10:41 pm
[Rick Turners]"Editorial brings in a DPX conform, color grade is done in Color with the appropriate LUT.. However your only available monitoring is say, a 24" FSI HD monitor or something like it. "
As a rule, I turn down DPX workflows going back to film.
Who picks up the cost if the color correction monitor isn't perfectly displaying the film characteristics? Some of these high-end guys doing this stuff update their LUTs weekly to compensate for batches of chemicals. LUT generation of any sort is traditionally very expensive.
No thanks.
I'm Rec 709 and proud of it.
IF - the client doesn't have the budget then I'll offer to CC to Rec 709 and they can take it to Film-out house that has calibrated settings for moving Rec 709 to film. I'm good with that.
But this is territory where I'm careful to be completely upfront about the specifications of my setup compared to the expectations of someone making the request.
Re: Indie DI with Color, questions.. by nick hasson on Aug 14, 2009 at 12:06:53 am
oseph Owens] "My experience is that pi's estimation of a DI house updating their LUTs on a weekly basis is not quite right. Usually its daily. "
I thought so - but I definitely didn't know so and I didn't want to be accused of being melodramatic.
- pi
We only do this at the end of a show, before we film out. This is about two times a month. But we only use the same Film recorder and the same lab. The labs have gotten allot better about hitting aims the first time around. Lately on The ugly truth and fame, we got near perfect prints. But there is always a little fudging with the printer lights to get a show print.
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 13, 2009 at 6:45:43 pm
Hi Rick,
This is the deal:
You should know which LAB is doing the filmout for you up front AND if they will give you their LUT to work with--which is sensitive territory for certain houses; a lot will not give out their LUT or they will not have it in the .mga format Color uses.
If you do not use the specific LUT for the LAB that is doing the filmout, you will not be able to get an accurate filmout with a log dpx sequence. It is virtually impossible. This is because each lab has their own custom printing densities which are derived from how they run their particular chemical/processing/etc.
However, if you grade from LOG dpx in Rec 709 space and export full range LIN dpx files, then your lab should accurately be able to use an inverse LUT to create LOG files in film space that work with their own system/printing densities. Unfortunately, you lose some dynamic range values by doing this, but it is arguably not noticeable. Also, you will not be working inside of the full gamut of film so some hues might shift. But a good lab will have the LIN to LOG conversion down so it should be real close and your tape masters will be entirely accurate.
For the monitoring: There is a difference in brightness and sharpness between a 2k projector and a broadcast monitor. There is also a difference in how many colors you are seeing on an FSI monitor (which does 8 bit) vs. an E-cinema monitor (which does 10 bit) or a 2K projector. Another consideration is the signal feed--are you sending it a dual link RGB signal or converting to YCbCr?
Ideally, you would monitor the image on a broadcast monitor over dual link with a full range RGB signal--It would be better to use a 10 bit display, but a good 8 bit will work fine too. Honestly, I wouldn't even use the LAB's LUT if it were available because they are set up for their RGB projectors, so it's still not going to accurately produce color on your monitor. Instead, I would let Color do the simple Log>Lin conversion, work in Rec 709, and export full range LIN dpx files.
Then you go to the LAB who is doing the filmout and do an overall adjustment using their Inverse LUT.
This is coming from experience. But I am sure the purists out there shudder at not delivering LOG files to a LAB.
Re: Indie DI with Color, questions.. by nick hasson on Aug 14, 2009 at 12:19:30 am
[Shawn Larkin] "Instead, I would let Color do the simple Log>Lin conversion, work in Rec 709, and export full range LIN dpx files."
This is a fantastic post.
Thanks Shawn. I've got this one bookmarked.
- pi
Patrick Inhofer
Finisher-in-Chief
Fini, nyc
I think before you do something like this, you should talk to the filmout house. Here in L.A Efilm has a way to deal with lin files to film. They can give you a few guide lines on how to grade your film in lin for a film out. This is not going to be dead accurate. But can get close. You have to be careful with your color palette. Blues can become cyan real quick. And reds can go crazy on film.
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 14, 2009 at 1:44:08 pm
Today, any decent lab should be able to work with lin dpx and do an inverse LUT.
The Efilm guys use Technicolor, which has this stuff down. I use FotoKem and they are excellent. As Nick points out, there are some gamma shifts because film cannot totally reproduce rec709 space (and vice versa). But I am positive that any lab worth its weight can do a very, very accurate conversion from lin rec709 to log to filmout to print.
Of course, I would always call the lab you are working with to make sure they know what you are doing. But I'm not sure there is anything a lab would tell you to do or warn you about with this workflow.
Finally--and this is for anyone that has done a filmout before--I don't think that a film print is the "best way" to see a projected image anymore. You lose a lot of information between film scan to film recording to print--no matter how good the lab is. So I think it is better to achieve a perfect grade in rec709 space, which will be perfectly replicated on tape masters and DCI projection masters. This way any decent digital projection or display will look spot on. And your print will look really close to spot on--you probably will not be able to tell much of the differences anyway. I have a few friends that are lab and color professionals which all grade in log space and basically think the same thing--they would prefer using the rec709 workflow that I described. But the purists would prefer that you work in log space the whole way through because there is more information there and that is the "best way" to do things. IMHO that workflow doesn't matter anymore now that labs have really accurate inverse LUTs.
Re: Indie DI with Color, questions.. by Patrick Inhofer on Aug 14, 2009 at 3:23:43 pm
[Shawn Larkin]"So I think it is better to achieve a perfect grade in rec709 space, which will be perfectly replicated on tape masters and DCI projection masters. This way any decent digital projection or display will look spot on."
Veering slightly OT - I used to tell my clients the picture will never look quite as good anywhere outside of the grading room.
After seeing some of my work projected digitally off HDCam here in NYC at some of the good theaters (SVA's new 23rd Street theater, MoMA's theater) I'm happy to tell them that's not true anymore. Digital workflows combined with (well maintained) digital projection means great looking images with very little compromise.
With the explosion in complexity of source material and deliverables - digital projection has become the best news for me in a very long time.
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 14, 2009 at 3:35:33 pm
I agree completely.
Digital projection has surpassed film projection in the last few years. The good 1080p, 2k, and 4k projectors can faithfully reproduce what you would see on a high end monitor--only much bigger. Since the better projectors can reproduce amazing gamuts, like DCI, anything graded on a good rec709 monitor should easily fit into / look good on a high end projector. Even the mid-range "pro sumer" and home entertainment digital projection I've seen can look really good if they're setup right.
Re: Indie DI with Color, questions.. by Neil Sadwelkar on Aug 15, 2009 at 4:21:26 pm
I would definitely advice staying with log if you're doing DPX. Color shows log files as linear out to a broadcast monitor connected through an AJA or Blackmagic card. And log files give you way more latitude to grade than linear DPX or other files.
About the LUTs and calibration that DI houses do... Don't really bother getting too deep into all that. They often use Truelight or custom LUTs, and no one will really share that info with an 'outsider' DI outfit.
Now, I'm going to propose a more 'common-sense' approach. Since you can't afford the big gun studio DI.
Get a good colourist, who's accustomed to looking at calibrated displays - monitors and projectors - and get test charts like Marcie or Macbeth. Most any experienced colourist can take a look at a Marcie on a display and tell you if its way way off.
After that, grade with a stable output device - monitor or projector - which won't shift colours in the course of your grading. Do a small sample. Send it out for film out. Time the neg if needed, on an analyzer, to get a correct print. You'll be amazed at how close you get it, even the first time.
After the test, grade the film in Color. Render out and send it for film out. If your monitor is not very accurately calibrated, there will be an overall colour offset, which can be compensated in the lab.
Mind that I've assumed that your monitor is very close to properly calibrated and if not, you've calibrated it.
When people shot the world around them with a movie camera. And before the advent of DI, they managed to print that neg into a good print, that resembled the reality they shot, didn't they? There were no LUTs, and lab monitors used with analyzers weren't very close to film. Still aren't.
No, I'm not saying that doing DI from log DPX files in Apple Color, without LUTs, is easy. But its not that earth-shatteringly difficult either. Give it a shot. You'll be amazed at how close to perfect you can get.
-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India
PS. I work with a DI team, 5 grading suites, 2k projectors with Truelight calibration, Resolve, Lustre, iQ. 40 plus full length features every year.
Trust me, you can get good results with Color without all that gizmo.
Re: Indie DI with Color, questions.. by Andrew Huebscher on Aug 16, 2009 at 4:30:04 pm
Rising Sun Research/CineTal have a nice 3D LUT creation program that is compatible with Apple Color, amongst others. They will also send you test patches to run through your workflow, deliver to a lab, send back to them, and then they will create a LUT for you based on that lab's print and a profile of your display.
I've tested their LUT creation software before and it works well. We also did a side-by-side comparison of grading identical footage in a linear REC-709 colorspace (filmed out at EFILM with their linear LUT), and using a 2383 print stock colorspace (also filmed out at EFILM using that stock's LUT) and saw a noticeable difference in color and density reproduction. The 2383 version had more dynamic range and a more filmic look. Source material was Super 16mm neg. transferred dMin/dMax to HDCAM-SR. So, for workflows with LOG source material (and I would NOT put RED in this category), my experience shows staying in LOG for a filmout looks better. Linear material worked well in REC-709, and matched up nicely to what we saw on our displays.
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 17, 2009 at 3:16:40 am
I don't think Rick Turner is following this thread anymore.
However, out of experience I can say that if you are not using your lab's LUT, I would expect shifts that you won't see in Color.
I think Color is a great DI tool. But unless you actually know what you are doing and are properly monitoring your footage in a color space that is universal, I would not simply export log files thinking that the lab will figure it out and know how to match your grade to their own private LUT. Won't happen. Your grade will not be "right."
Also, using Sun Research's LUT creation software is not going to be useful if your lab that does the film-out has wildly different printing densities or other peculiarities than what are considered standard--and most do.
Re: Indie DI with Color, questions.. by nick hasson on Aug 17, 2009 at 6:55:27 pm
it is important to remember that a lin to log conversion is not all that is needed. I have a great lin to log conversion. All this does is change color space.
If you color in Lin and covert to log for a filmout, you are not taking into account the characteristics of the filmout, the recorder, the labs bath, the stock your shooting out on. Thats what the lut is doing. It's more than just a simple lin to log conversion. Now a lab might have a conversion that takes this into consideration. And if they do, you will want to look at this during color timing. Filmout a test section with that conversion and see what happens.
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 17, 2009 at 9:12:40 pm
The problem with handing any lab log files when you are not doing the color grading at that lab, is there are too many variables--especially if you have not replicated how they are set up for coloring using their specific LUT and monitoring conditions.
If you hand them files graded in a universal color space (like Rec709) that are lin, the lab can derive anything they want from them--as long as they have an inverse LUT which maps rec709 values to their processing/printing. Most have this.
What would happen is you would give them the files in lin, look at them with their lut applied to see that the conversion to their film space is right and then the lab would render out log files and do the rest. When a print is struck, you watch with a timer to tweak what is necessary.
If you hand a lab log files graded with your own standard conversion or a lut you created from another program, then their is a lot more tweaking and guesswork the lab will have to do to convert those into values that work for their own particulars.
What I keep saying is that you will lose some information if you hand in lin files, BUT you will gain time since you will not need to do all the tweaking necessary to try to derive what you were seeing without the lab's LUT in place. And the loss of information--in my opinion--is not noticeable at all.
Hell, I say spend all that time/money in the DI room trying to fix your grade because you didn't have the right LUT in place. Why come prepared with an indisputably "right" looking lin file and only have to do one conversion?
Re: Indie DI with Color, questions.. by Shawn Larkin on Aug 17, 2009 at 11:22:55 pm
Hi Rick,
If you do go with the workflow I described, which is more affordable, accurate, and accessible than typical DI, there are a few things you should keep in mind:
1) You really should be viewing everything in RGB, which means you will have to work with a dual link or 3Gb SDI card and monitor. And the monitor should be a quality broadcast monitor with good color reproduction (obviously).
2) When you bring the rec709 full range lin dpx files to the lab, you will still want to double check what they look like with the inverse LUT in a DI room. You may have to do a very basic overall change to the show for filmout, but this tweak should take minutes--not hours--to do. We're talking like pushing the mids up 1% or crushing the blacks more or something like that.
3) Lastly, as mentioned in this thread, some video colors cannot be reproduced in film space. So certain hues may shift slightly. But the same holds true if you grade for film space and go to rec709 for tape master or rec601 for DVD--some colors have to shift a bit when going from one space to the other. But this shouldn't be very noticeable unless you graded to the outermost edges of the rec709 space, which most people don't.
