Downres Raw files without losing information

[Jeremy Haccoun]

Hello,

I'm working on a film that has been shot in RED RAW 5k and since I'm finishing in 2k, I need to downres everything to 2k before color grading to make my workflow smoother.

However I don't want to lose any of the information of my original 5K RAW footage. Is it possible to downres Red raw footage without losing any of the information/color range? How about DPX files?

Thanks

 

[egon touste]

Hello,

I'm working on a film that has been shot in RED RAW 5k and since I'm finishing in 2k, I need to downres everything to 2k before color grading to make my workflow smoother.

However I don't want to lose any of the information of my original 5K RAW footage. Is it possible to downres Red raw footage without losing any of the information/color range? How about DPX files?

Thanks

jeremy, the scientific answer is no ..but thats not the answer you want

the answer you want is .. pretty much.. tiff or dpx will do the job .. but make sure whichever you choose is using 48bit (ie 16bits per red /green/blue sample), and make sure you preserve as much range for the grade (use your histograms and such)

dpx often come in 10bit log sample form.. but you may want 16bit samples, or 16bit log samples perhaps .. if you want to maximise your grading range

 

[Christoffer Glans]

Hello,

I'm working on a film that has been shot in RED RAW 5k and since I'm finishing in 2k, I need to downres everything to 2k before color grading to make my workflow smoother.

However I don't want to lose any of the information of my original 5K RAW footage. Is it possible to downres Red raw footage without losing any of the information/color range? How about DPX files?

Thanks

In what software will you do the grading? If resolve, don't bother with DPX's, just work with the RAW files and if you need speed, render the first node cache after you set a one-light and RAW settings for each clip. After that, grading will work without a slow process.

 

[Marc Wielage]

I'm working on a film that has been shot in RED RAW 5k and since I'm finishing in 2k, I need to downres everything to 2k before color grading to make my workflow smoother.

If you get a better computer, you can use the original 5K files and downres them on the fly. It'll work fine on a trashcan Mac in HD.

You could theoretically debayer and convert to ProRes 444 with RedColor4 or DragonColor and RedLogFilm, and that can work provided you adjust the ISO and color temperature correctly in the debayer. It's done all the time for TV. But you really have to stay on top of the exposure and color temperature.

 

[Jeremy Haccoun]

Many thanks for your answers - My whole workflow is Adobe and I'm color correcting in Speedgrade.


At the moment I am testing with the 5k RAW files in Speedgrade and it's okay, but I can tell that exporting the whole timeline will be too heavy. Also I'd like to get real-time playback in Speedgrade, which I don't have in 5k.


I don't need to compress the files, my computer will handle and play uncompressed 2k files, but I will only do it if I'm 100% sure I'm not losing anything in the process. So my best bet is DPX at max depth?

 

[Stefan Scherperel]

If you are working for a 2K final, I suggest setting up a 2K timeline and then selecting the clips, right clicking and press scale to frame size. This should copy over to speed grade and allow for much better performance.

 

[Dr. Sassi]

Raw is the representation of the Bayer-Pattern, as mentioned above. As others said, there is no downscaling and keep a R3D. That would require a "de-bayer, scale, re-bayer" process, not available, nor suggested.

If you really want to get all information (while avoiding working in R3D) and have the most precise representation of your de-bayer setting: Open EXR.
It has 1024 steps per stop in half float already (that is more per stop than you can use in 10bit-log files normally completely [95/685], the suggestion would be different for distribution here perhaps). I asked Graeme a while ago, and he confirmed that you get from RedCineX a clean linear file out with Open EXR.

I would certainly avoid anything that has REC 709 as color space, as it is more like sRGB, which means the smallest possible color space, for intermediate files. As delivery colorspace -- again: different story.
(Yes I'm aware it is not the same, REC 709 has in the darks a linear "curve" and sRGB has not, besides that the gamma curve is slightly different as well, ;o)

DPX, was good -- see ACIS for example, I avoid it -- if possible, but as final delivery format for a print I have used it.

 

[Marc Wielage]

I would certainly avoid anything that has REC 709 as color space, as it is more like sRGB, which means the smallest possible color space, for intermediate files. As delivery colorspace -- again: different story.

ProRes Log works fine. It's done every single day of the week on television and does hold all the information you would ever need. I'd still rather have the raw file, but ProRes Log can suffice in many (if not most) situations. Ditto with DPX log.

 

[Jeremy Haccoun]

Perfect! Thank you for your detailed answer. Does it matter whether the conversion to OpenEXR is being done from After FX or RedCine, and are there any specific settings to select in the OpenEXR export options?

 

[egon touste]

Perfect! Thank you for your detailed answer. Does it matter whether the conversion to OpenEXR is being done from After FX or RedCine, and are there any specific settings to select in the OpenEXR export options?

well.. you're thanking someone for pointing you to EXR files.. so..

whether EXR is better, or worse than tiff depends on the sample depth. EXR can use 16 or 32bit colour samples. 32bit will make your files twice as big, 16bit IEEE is..not really any better than 16bit integer samples..

if you are using Adobe, the question is simpler..you are able to simply use your original R3Ds throughout .. which is the one format that will provide you with everything that was recorded, and better than DPX, TIFF, or EXR

USE R3D.. DO NOT USE EXR!!!

 

[Jeremy Haccoun]

Hi Egon, thanks can you tell me a bit more ? Where would the downres happen? When I send my R3D 5k Premiere timeline to Speedgrade, Premiere writes 5k DPX files for each clip, correct?