Beginners Guide to Colour Grading

[alexpeden2000]

Ah so you could just convert the old source to TIFF, make a LUT for each scene in the Dre tool and then go into Resolve and apply the LUT to the corresponding scene in the newer source?

[DoomBot]

The way i do it is have the source video used for color on one line and the video you want to regrade underneath. In my case i use Adobe Premiere. Like PDB said, cut up the file you want regraded into shots, once you have the 2 videos lined up. Then it's a matter of going through each shot and grabbing one PNG or TIFF frame from both sources, then using Dre's tool to match and create a lut for each to be used.

[PDB]

The way i do it is have the source video used for color on one line and the video you want to regrade underneath. In my case i use Adobe Premiere. Like PDB said cut up the file you want regraded into shots, once you have the 2 videos lined up. Then it's a matter of going through each shot and grabbing one PNG or TIFF frame from both sources, then using Dre's tool to match and create a lut for each to be used.

I concur with what Doombot said.

[alexpeden2000]

Yeah think I’ve got it now, I didn’t realise that VirtualDub can also export frames as TIFFs so I’ll probably just use that for lining up the sources and getting the files for the Dre tool.

I know it’s likely to vary but how many LUTs are you likely to need for a 2 hour film for example?

[PDB]

Yeah think I’ve got it now, I didn’t realise that VirtualDub can also export frames as TIFFs so I’ll probably just use that for lining up the sources and getting the files for the Dre tool.

I know it’s likely to vary but how many LUTs are you likely to need for a 2 hour film for example?

If you go shot-by-shot its likely to be in the thousands depending on the the length and editing style. If you go scene-by-scene it can be in the hundreds.

[alleycat]

Something else to consider is the way the two sources are framed as with Dre they need to be the same or very similar. If one source has more image top and bottom you need to crop it off so the two match. You could manually crop each image but that adds to the time taken or you can pre crop in avisynth or Vdub etc. Just keep an eye on it if you do that as the amount of crop required could change in different scenes.

Also Dre sometimes introduces black blocks in the middle of bright whites so keep an eye out for this as you go. When it happens you can play around with the settings. Some projects work on 100 color spaces with little issues, some I find I need to drop to say 50-60 or I get issues every shot. You’ve also got tte smoothing if you’ve got a rough source. If I’m taking color from a low quality DVD or VHS then 50 spaces and 0.5 smoothing seems to be a good starting point but you just need to experiment. More spaces the better but you just have to go with what works. Sometimes you just have to give up and use a different frame.

Finally come up with a good labelling system for all your images and cubes. When you get into the hundreds it can get quite confusing.

Good luck!

[alexpeden2000]

Thanks Alley Cat, some really good points there. I actually experimented with The Silence Of The Lambs fullscreen LD and the 4K and I noticed it didn’t work with the different image sizes so what you said about cropping makes sense.

[alexpeden2000]

Finally got round to giving this a proper go, getting some nice results with the Dre tool but have a question for the experts. Clearly shot-by-shot is the way to go to get accurate grades but what do you do when you have a dissolve between shots? I've found if I put a cut point at any point in the dissolve, I get a 'jump' in the grade as I'm using a different LUT either side of the cut point.

Would it be better to avoid using cut points when there are dissolves and just use the same LUT either side?

[PDB]

Yep shot-by-shot is best if you can stomach doing all the work. It can get tedious.

So it sounds dumb but it took me forever in the beginning to figure how to do dissolve shots and it turned out in the end to be pretty simple.

You pick the midway point in the dissolve shot and cut it into two separate shots. You grade both sides with Dre and then all you do is drop a cross dissolve effect on that middle cut you made. You can then drag the dissolve effect out as needed.

For fade to blacks or white you can do the same thing but just cut out the black or white part into its own section and add two dissolves on both cuts.

Hope that makes sense and helps.

[alexpeden2000]

Thanks PDB, that’s a great idea for dissolves - looks like they’re easy to add in DaVinci so will give it a go. Not had any fade to blacks/whites yet but would you need two LUTs in that situation normally?