original files vs. a rendered file
The first thing to keep in mind is that sending the original footage is sometimes not optional, depending on the project.
Using the original files or a render can both be very beneficial or make life very complicated. Which one is true varies per project and there is no one-size-fits-all solution.
This page gives you a generic pros and cons list, but every project would ideally be analysed by a professional before this decision is made.
8-bit vs. 10-bit
Regardless of the workflow, you need to make sure you deliver (at least) 10-bit files to us.
The codecs mentioned below are all 10-bit, so if you stick to them, you should be good to go.
However, if you lowered the quality of the files (ie.: by making proxies) on Premiere Pro or AVID to make editing smoother, the video gets compressed and the color information brought down to 8 bits.
If you then export a 10-bit file for grading, the software will still use 8-bit source files. This means you may deliver us a 10-bit file, but the images contained within this file are still 8-bit.
8-bit color makes smooth color gradients look quite ugly. Blue skies and bokeh suddenly look very low quality.
It is very hard to notice that a video is 8-bit when looking at ungraded footage. The ugly artefacts only show up once the colorist starts pulling the colors back.
At Color Space we usually refuse source material that is 8-bit (or 10-bit that looks like 8-bit), unless the actual camera files were originally recorded in 8-bit. In that case there's nothing to be done and the grading possibilities will be limited.
Sending a ProRes or DNxHD/HR "mixdown" file:
If you shot compressed video (like log footage in XAVC, ProRes or DNxHD/HR):
1080p or lower: a 10-bit codec such as ProRes422 HQ or DNxHD 185x.
Resolutions higher than 1080p: ProRes422 HQ or DNxHR HQX 10-bit are good choices.
Higher flavors of ProRes are usually overkill for most cameras, generating big files. But further not a problem.
If your original footage is 444, then you can make a ProRes 4444 or DNxHR 444 10-bit file and still retain the quality.
If you shoot compressed (not RAW) using ARRI cameras, you have to disable the built-in LUT which comes in each video file before making the export for color. You can do that easily in the editing software.
Using the original files:
If you shoot RAW formats (like RED, ARRI or Blackmagic RAW), you can’t make an export without losing important color data. In that case we need the originals. It can be a bit inconvenient, but it may offer more flexibility/quality in grading.
If you shoot compressed (not RAW) using Arri cameras AND using an embedded (NOT burned into the footage) LUT, then we can only access that LUT during grading if we receive the original camera files.
How to decide in case of ARRI footage:
As you see above, with compressed ARRI video, you have the option of either a render or original files.
The easiest way to decide whether to send a ProRes file or the originals, is by asking yourself (or the DP) if the colorist should take the embedded LUT into account.
If that LUT is an important part of building the look, then it’s better to send the originals.
If you believe the colorist will be fine building his own look based on your input, then disable the LUT in Avid/Premiere/FCP and send us a mixdown file.