Hello everyone,

I'm starting to get a coherent workflow together using Kdenlive and MLT tools, but at the moment what I'm really lacking is a good color correction and color grading strategy.

This has been on my mind quite a bit recently, since I have a few short films which are finished but in desperate need of a final overall "look" to glue the various scenes together. This is really the last piece I need to complete my general workflow.

I've read Granjow's tutorials, which were very helpful for understanding the analysis tools, but he only briefly mentions secondary color correction in passing at the end. I like the examples he gives, but unfortunately he doesn't go into detail of how he got there:

http://kdenlive.org/users/granjow/introducing-color-scopes-vectorscope

What I'd like to know is:

1) Has anyone developed a good strategy or personal recipe for color correction and grading in Kdenlive?

2) How can you create masks and select ranges for secondary color correction in Kdenlive?

3) Does anyone use other programs in conjunction with Kdenlive (Blender, for example) to do primary and/or secondary color correction? What is your workflow?

Many thanks in advance!

Just a few hints how to do some secondary (non-global) color manipulation in Kdenlive:

1. Level-selective: (lows, mids, highs)
Use the "curves" tool. The three points are movable in two dimensions, so this tool gives you more options than the traditional "color wheels"!
Three point balance will do level-selective color shifts too, but is a bit counter intuitive, as it moves the color AWAY from the selected color. This is good for removing unwanted color casts (white balancing), but not so handy for creative color manipulation.

2. Color-selective: (based on hue, saturation....)
First, make an alpha mask using the color selection tool. Next,
For simple adjustments, use RGB adjustment with "Alpha controlled" ON.
For more complex tasks, composite the image with itself, then use any color tool, or a combination of them, on one or the other track. The only thing that will not work well this way is hue rotation, because it is not a linear operation.
btw, the new key spill mop up tool could probably also be abused to do some color dependent color change, directly, without the compositing step.

3. Position selective:
Use rotoscoping to make the alpha mask, then proceed as in 2.
For very simple masks, alpha gradient could do too.

Garp, thank you for sharing your workflow.

I'm actually quite excited about the SOP/SAT filter because of its relation to ASC CDLs, which (if I understand correctly) open the possibility of reusing and sharing color correction recipes. I don't know in practice yet how useful this might be, but it sure is an interesting idea.

I downloaded and tried to install Davinci Resolve Lite a few months ago, but from what I could glean from the failed installation message (while installing Visual Studio I think), I need Windows 64, and my Windows machine is 32 bit. Can you confirm this?

You're right that Kdenlive can't export EDL. I'm not really sure of the reason for this (probably low priority on the developers' to-do list), but in my case it wouldn't help anyway. CMX 3600 only works with reel names and timecode baked into the file, and my DSLR doesn't do that, so that type of EDL is quite useless for my purposes. I can only work with progams that read from absolute file names and locations. In any case, one of the reasons I like Kdenlive is because a .kdenlive or .mlt file is pure XML. It's very complex XML, so you need a script to parse it and pull out the relevant information. Fortunately it looks like someone has already written such a script in Python. I haven't used it myself, but it's worth a look:
https://github.com/barry-lyndon/KdenParse

I've written scripts to translate XML from other programs to Kdenlive/Melt, but I haven't tried the other way around yet. I'm not sure what kind of XML Resolve needs, but you might be able to write a translation script in Perl or Bash (or whatever your language of choice is).

I also find Blender fascinating and overwhelming at the same time. I want to learn more about it, but I reckon the learning curve is about as steep as any program I've encountered.

Marko, THANK YOU for your very clear and specific advice about masking. I'll give your suggestions a try this weekend.

Thanks for explaining the three-point balance to me. Until now I couldn't figure out why it acted so "funny". I'll have another look at it.

You're right, so far curves have seemed to be the best tool for color correction in Kdenlive. Some questions I have, however, are: for Curves and Bezier Curves, do you need to create a new effect in your stack for every channel (R, G, B, luma)? I'm used to using Photoshop, where one Curves layer can contain adjustments to all four, so I'm not sure if I'm doing it right in Kdenlive. Also, is there any way to keyframe the Curves effect or the opacity of the effect to account for slight changes in the color/lighting of the shot?

A big thank you to both of you for your help!