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Displays and Color Correction

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I have a 43' plasma screen I am using to correct and grade for a feature film. I'm a bit confused about Rec 709. What I think I understand is that it is a standard color gamut used across many displays, including my plasma screen. I've gone in to the color settings under display on my computer and found that I can change the display profile of my plasma screen. The display was set to HD-709-A by default it seems. Is this safe or should I choose another option like HDR HDTV Display (Rec 709) - EOTF SMPTE 2084 or HDTV Display (Rec 709) - EOTF Rec. 1886 (Gamma 2.4) OR should I calibrate the display? If so, under what parameters (white point, gamma, etc.)?


Another issue I have is that I don't know if I should grade on a Rec 709 display if the film will be largely distributed over streaming services to be viewed on home computers. Or if I should make two separate grades, one that is sRGB friendly and the other Rec 709.


Any advice on this matter is welcome and much appreciated!





Edited by Nicholas Lorini
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I do post color work, so I'll chime in here:


First, Rec/BT 709 and sRGB are practically the same thing. There is no visual difference between them.


Second, you should only grade a film on a monitor/projector that is not only RATED as capable of 100% of Rec/BT709 and/or sRGB, but you also need to get that display calibrated to ensure its actually displaying that. You can use probes for this, which run several hundred dollars.


Third, there is not really any monitor out of the box (especially consumer TV's and displays) that I would say are 100%REC/sRGB compliant without being calibrated. Just because the box says '99or 100% sRGB" does not mean you'll get that out of the box.


Fourth, No need for two separate grades. As long as your first grade is done on a properly calibrated monitor in rec709 or sRGB, you can deliver the project in that format for home video and streaming. If you're doing a DCP for cinemas, you'll need to do a LUT conversion from Rec709 to P3 color space.



Edited by Landon D. Parks
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Thank you for your input!


Only problem here is that I'm working on a no budget film so I'm not sure "several hundred dollars" for probes is in the cards. Is there any way of getting reasonably close on my own?


The film will screen in a theater for its premiere but unlikely ever after that. Though, I guess since it's been brought up, I'm not totally clear on LUTs either. I understand that they can be a reference but also a sort of preset grade as they seem to be applied to my image when I use them. They're also terribly dramatic oftentimes and I find more subtle tinkering in the curves and wheels and such to do the trick. It also may be worth noting most of the footage I'm working with is shot on a C100 without any external recording device.

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I mean you can skimp on the color-calibration, and if your project is mainly web-based it's probably fine to grade on a standard computer monitor - just keep in mind that you might not be seeing accurate colors. When this means is that what you see, and what others see might not be the same. As long as you're willing to work within this constraint, then go for it.


You don't need a setup like mine, but if you're planning to do color work at all, it's best to invest in a monitor capable of at least '99% sRGB', and then buy a $150 probe to get it as close to sRGB as possible. Once you have it as close as possible, you can deliver the project in pretty much any color format by utilizing LUTS. A LUT is simply a look-up table of colors. For example, playing a Rec 709 file on a DCP will look like crap - the colors will be slightly off and contrast will suffer. Basically, its goal is simply to keep the image looking the same in different color spaces.


If you're planning to try and sell this, or enter it into film festivals and such, then a calibrated grade WILL make a difference. It's just up to you to determine how important that is.

Edited by Landon D. Parks
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I work in DCI-P3 color space. I think with DaVinci, it's the best way to roll. Rec709 can get you in trouble for deliverables and it's super easy to convert P3 to Rec709, DaVinci will do all the work necessary in program.


With all that said, there are cheap solutions to color grading monitors. I nabbed a LG 31MU97-B on ebay for around $650 shipped. It's a great entry level 4k monitor that's super easy to calibrate. Its not perfect, but it's a great start.


Then all you really need is a faster computer, decent graphics card and maybe a color pallet. I mean color bays are very expensive to setup. I just spent a few grand tweaking mine because it needed it. Now I can do anything, period. :)

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The monitor decodes the DCI-P3 internally. So you give it the P3 color space and simply select P3 decode in the menu and you're all good to go. Also, I use a blackmagic 4k I/O card. I think it's a requirement when using DaVinci with any other output then Rec709.


I'm being forced to work in 4k, so the cheapest solution is a LCD display at the moment. Plus, home theater DLP projectors have heavy limitations in the highlights, they tear when they get near white. So you have to color way below 100% white, which isn't accurate coloring at that point. I struggled to color on my calibrated DLP projector properly. It was a great idea at first, but I always found myself annoyed by the tearing and 8 bit look of the whites. I colored on a beautiful $30,000 grading monitor recently and said, that's it... I'm investing. This monitor I got (which you should look into) is a 10 bit panel, so it doesn't have any of the issues the DLP projectors have.

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I think no monitor can be used for ANY color work without calibrating it first with a probe. calibrating with eye is not accurate enough because the eye cheats color and contrast and has "auto exposure" and edge enhancement etc.

If you can't afford even a very basic calibrating tool, then just borrow one from a friend. one can grade even with a reasonably priced computer monitor (I have done lots of indie grading with iMac displays for example and they are totally fine if properly calibrated but totally useless if not calibrated properly like any other monitor out there) . I think the gamma and brightness is more of a problem with uncalibrated monitors... the colors you can get somewhat right with gut feeling if having enough time but the gamma , contrast is very difficult to nail without tools

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I think you're in a tough spot here. But I'll try to help.


First a few questions:


What computer?

What grading software?

What is the model of Plasma?


And, you're going to need to spend a little money i think...



1. You might find that Resolve doesn't work so well on your MBP. You will almost certainly need the more expensive model with the separate video graphics card installed. I did do a quick grade for a TV pilot presentation last year on my MBP and it did work ok in 1920x1080 resolution form ProRes 4444 Alexa files. It is the top of the line (2013) model though.


2. Since you're on a mac with Resolve, you're going to need a Blackmagic Mini Monitor device. It takes video via thunderbolt to HDMI for your plasma. About $150.


3. Calibrating your display. Plasma displays are tough to calibrate using an inexpensive device such as the iOne Display probe and iOne software. ($250) There are a few issues here. First, the display will not store the calibration, it will be stored in the OS. But, this calibration will not be applied to the display through the Mini Monitor device, and you need the mini monitor device to see full screen video from Resolve.

Secondly, there is an energy saving "device" in the plasma "ABL / auto brightness level" that can not be turned off. It means that a full screen of white is not the same value of white as a small patch of white. iOne software can not deal with this at all. The calibration will fail.

So you have two choices here: Have a professional come to you and calibrate the plasma with professional tools using only the adjustments in the display (about $350), or set the plasma to it's best possible state by setting the display to REC709 (ie. not wide gamut). Set gamma to 2.4 (my panasonic plasma at home doesn't look right at 2.2 gamma). Use standard picture proifle (not cinema or THX or vivid), set the "brightness" control by looking at the pluge pattern from colorbars set from Resolve through your mini monitor, and set the "contrast" so the picture is not too bright. As for "color temp", I have no idea which setting on your display comes closest to 6500k.


To check your settings (as best as you can for no money), play a blu-ray disc of some movie that you're familiar with and see if it looks good. If it does, your work should be presentable, if not very accurate.


Since, the more I think of it, your head is probably spinning by now... Cal David Abrams 323 679 4079 to discuss calibrating your model of plasma and see what he thinks, and will charge. If he says it's not a good candidate, get yourself an FSI display which comes calibrated by the factory and get to work. ($2000+)


Good luck!

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