xyz color space in Premiere Pro and After Effects

[Bryce W.]

I am trying to make my first DCDM and realize that one of the specifications is xyz color space. The only thing I found in the two programs mentioned was a X'Y'Z' (Gamma 2.6) 5900K in After Effects. I don't know if this is correct with the Kelvin setting.

I've been reading up some places how people will used matrices to do color conversion...do you need a specific program to do this?

The other problem I'm having is that on my imac (xyz) isn't an option for the monitor's color space.

[Danko Dolch]

Hi Bryce,

good question about the white point - the X'Y'Z' profile is used in AE to do a DCI compliant color space transformation.
In combination with the free Fnord J2C plugin for AF and Premiere you could also export DCI compliant JPEG2000 code stream files...

RedGiant LUT Buddy would be a good starting point to further investigate custom LUT's. (currently doesn't work with Premiere CS6)

XYZ never will be a monitoring color space but an universal mastering color space to store digital cinema images. You have to transform back from XYZ to monitor RGB using a propriate display LUT.

Best Option would be to use a Display supporting DCI P3 RGB monitoring.

[Danko Dolch]

regarding white point:

"...the white point in the DCI spec was designed to favor lumens by using a color temp closer to the natural Xenon spectrum. I think it's somewhere around 5500K..."

source: http://www.avsforum.com/t/1126589/sm...n-in-hollywood

[Bryce W.]

Danko, if you are using a monitor that has an srgb color space, is it only possible for that monitor to guess at what the DCI-P3 color profile might look like?

I ask this because I am using an imac. I don't understand why it would have a 'wide-gamut rgb' option for a color profile if imacs are supposed to be near srgb.

Hi Bryce,

good question about the white point - the X'Y'Z' profile is used in AE to do a DCI compliant color space transformation.
In combination with the free Fnord J2C plugin for AF and Premiere you could also export DCI compliant JPEG2000 code stream files...

RedGiant LUT Buddy would be a good starting point to further investigate custom LUT's. (currently doesn't work with Premiere CS6)

XYZ never will be a monitoring color space but an universal mastering color space to store digital cinema images. You have to transform back from XYZ to monitor RGB using a propriate display LUT.

Best Option would be to use a Display supporting DCI P3 RGB monitoring.

[Angelo Lorenzo]

If you've never created a DCP then understand that it's an involved process and you should either 1) let a mastering house do it or 2) have access to a theater with digital projection to test.

It is my understanding that some of the open source DCP tools will convert RGB representation of P3 to the XYZ representation. It's also my understanding that many of these tools will also do a Rec 709 to a P3 conversion.

P3 is just the cinema color space, it has a wider gamut and allows for more saturated colors. Rec 709 (standard HD), if it was color graded on a Rec 709 monitor should look fine after the conversion, you just don't have the ability to take advantage of some of the subtleties P3 can afford you if you aren't grading with a P3 monitor.

If it looks good on a Rec 709 monitor then it's "in" the Rec 709 space, if it looks good on a P3 monitor/system then it's "in" the P3 space. Rec 709 to P3 conversions (usually through a LUT transform) work because it's a smaller colorspace being mapped onto a larger one. The XYZ conversion is just "future proofing" things. http://thepostlab.com/pitch-perfect-...olor-workflow/ for a bit further detail.

[Bryce W.]

If you've never created a DCP then understand that it's an involved process and you should either 1) let a mastering house do it or 2) have access to a theater with digital projection to test.

It is my understanding that some of the open source DCP tools will convert RGB representation of P3 to the XYZ representation. It's also my understanding that many of these tools will also do a Rec 709 to a P3 conversion.

P3 is just the cinema color space, it has a wider gamut and allows for more saturated colors. Rec 709 (standard HD), if it was color graded on a Rec 709 monitor should look fine after the conversion, you just don't have the ability to take advantage of some of the subtleties P3 can afford you if you aren't grading with a P3 monitor.

If it looks good on a Rec 709 monitor then it's "in" the Rec 709 space, if it looks good on a P3 monitor/system then it's "in" the P3 space. Rec 709 to P3 conversions (usually through a LUT transform) work because it's a smaller colorspace being mapped onto a larger one. The XYZ conversion is just "future proofing" things. http://thepostlab.com/pitch-perfect-...olor-workflow/ for a bit further detail.

In your opinion how big are the subtleties with regards to Rec 709 and P3, and the look of the film? If I remember correctly, P3 has more saturated greens so does that mean the look of your picture will change significantly if, for example, you are shooting in a rainforest?

I am not very familiar with LUTs but I do have one question concerning them:

If you have an srgb monitor and have footage in srgb but want to color grade it to a color space larger than srgb, is it possible to use an LUT to convert an srgb color grade to that larger color space? I mean, if the software knew the values of the larger color space it could make a conversion...is this possible?

[Angelo Lorenzo]

In your opinion how big are the subtleties with regards to Rec 709 and P3, and the look of the film? If I remember correctly, P3 has more saturated greens so does that mean the look of your picture will change significantly if, for example, you are shooting in a rainforest?

I am not very familiar with LUTs but I do have one question concerning them:

If you have an srgb monitor and have footage in srgb but want to color grade it to a color space larger than srgb, is it possible to use an LUT to convert an srgb color grade to that larger color space? I mean, if the software knew the values of the larger color space it could make a conversion...is this possible?

The ability to grade in P3 is nice but if you don't have the budget to facilitate it, it's not the end of the world. It's the sprinkles on the cake but P3 won't rescue a poorly exposed shot much more than grading that same shot in Rec. 709.

In terms of a LUT, you have to colorgrade within the color space you can actually see otherwise you're making some serious guesses. Yes you can transform Rec 709 to P3 because, mathematically you're mapping it to the colors that are equal on a P3 screen. A P3 image will look brighter and more green on a Rec 709 monitor. If you have the budget, some people like doing this conversion and then spot checking on a P3 screen to allow them to adjust some scenes if needed. It's generally a very accurate conversion and many low budget productions who never planned for projection end up doing it this way.