Live Call – Coding DCTLs Wrap Up Discussion with Cullen Kelly

December 9, 2021

Cullen Kelly wraps his 10-part intro series about Coding DCTL. It's a live Q&A session answering questions, while Cullen learns something new!


Cullen Kelly takes questions from Mixing Light members

This Insight is a replay of our very first Mixing Light conference call with our members. Unlike webinars, a conference call allows members to turn on their cameras and directly interface with our Contributors. Watch this Insight to judge for yourself, but we think this was an excellent call and a successful proof-of-concept.

You can be sure we’ll be doing many more of these on Mixing Light.

Discussion Topics

(Note: timestamps in bold red are member questions. This call was slightly cut down to remove dead air.)

Start: Introduction and Welcome

1:36 – Color-coding the overlay created in Part 9 of this series

5:27 – Is it possible to create custom Hue vs. and Sat vs. curves?

9:04 – Has Cullen cracked the formula that Resolve uses for its Sat vs. and Lum vs. curves?

10:25 – Cullen talks about the DCTL he’s coded to calculate Hue vs Sat in the HSV color model for a form of subtractive color

11:09 – The opportunities generated by coding your own DCTLs

13:15 – Discussion about color-aware keying tools in Resolve 17

14:56 – Building your own ‘color space aware’ tools: Thoughts and approaches

19:40 – Can you use black as a reference point to create a ‘color space aware’ DCTL?

20:44 – Exploring the idea of working with Resolve Color Management but doing all the color management in the node tree.


22:40 – Understanding and moving beyond a 3×3 color matrix

25:03 – Does it make sense to create a DCTL for mapping SDR to HDR at the timeline level?

26:06 – How to select a range of pixel values and then change them to a specific color?

30:26 – Can a DCTL address external hardware? What are its limitations?

32:20 – You learned more than you think you did in this series. This is Cullen’s live demo of using an ARRI white paper to build your own Log-C conversion.

43:27 – Why you may want to replace Resolve’s built-in image transforms with your own DCTL.

45:40 – Cullen is taught a huge timesaving trick while coding!

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Homepage Forums Live Call – Coding DCTLs Wrap Up Discussion with Cullen Kelly

  • Brix B

    Thank you Cullen for all these precious videos.

    In addition to Kevin’s shortcut, I would add the cmd+shift+d to duplicate a line when cursor at the end, instead of copy-pasting it.

    Moreover and so to make the text more readable in sublime text, you could also read all .dctl documents through the “C” language implementation. To do so, from the bottom right tab of the editor (where is “plain text” written in these tutorials), choose “open all with current extension as…” and pick up “C”. The DCTL should look better this way.

    Thank you again and looking forwards to further explorations.

    Attached, I have implemented the logC4 new arri curve based on your explanations and dead match. thanks

  • Cullen Kelly

    You’re very welcome Brix! Great suggestions, and congrats on getting LogC4 implementeed!

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