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Color correction card / flat color profile interoperation


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Hello there!

 

I'm a newbie in video production (although, with some experience 😉 )
and definitely newbie in color grading.

 

My software: DaVinci Resolve 17.

 

ATM I'm curious on the following:

 

I have a video footage in flat (or e.g. LOG) color profile.
If I use color correction card,

71JosVjNftL._AC_SX450_.jpg

 

making my video, should I use
color conversion function, e.g. special LUT for transforming LOG to Rec709?
Or I can just match colors from the color correction card (and it will be enough) ?
(DaVinci Resolve can do it - select card and draw the rectangle above the card on video)

 

So if I have color correction card - do I still need "remove LOG" operation with special LUTs and/or software functions?

 

Another question, which follows previous one:

 

What if I have a footage, taken without LOG/Flat profile?
E.g. on smartphone (not FilMiC Pro or similar!) or old GoPro without ProTunes?
Can color correction card help me in adjusting (often, oversaturated colors on smartphones) stuff for my postprocessing?
Or, if I have smartphone footage - it is definitely unrecoverable garbage...? 😉

 

Any ideas will be highly appreciated!

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I have tried using the “auto” transform from a card in Resolve. Sometimes it works, other times, strange result and I don’t know why.

If you are successful, place this transform node in the middle of your node tree. You will find, I think, that this correction node, while accurate, may clip highlights and shadows. To fix this, use the nodes before the transform to bring back missing highlights or shadows using the lift or gain controls.

Its possible your log to 709 LUT may do a better job if it was created for your particular camera. But the same technique applies. Use nodes before the LUT transform to adjust highlights and shadows.

I think you will find it very difficult to simply normalize this chart log image by simple color correction adjustments. But, give it a try as you will learn a bit!

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Posted (edited)

Here is a totally free, but very intense, training program for DaVinci Resolve that will answer all your questions within the context of operating Resolve.  While it is program specific, the concepts of color management are pretty universal for all grading programs.

https://www.blackmagicdesign.com/products/davinciresolve/training

Scroll down to training books and download the book and video clips.  You can even be certified by Blackmagic for free.

I took it when version 16 was in effect and it was very good.

However, the basic strategy is to choose a wide color gamut (like DaVinci Wide Color Gamut or Rec 2020) that will easily encompass all your source color spaces, regardless of origination (log, Raw, Rec. 709 etc.) and use image transforms to translate these divergent color spaces to a "universal" color map.

Once you have transformed and normalized your shots to a neutral, balanced timeline, THEN grade for the look by applying your style and/or using creative LUTS to a finished look.

When locked, then your finished job can be exported and mapped to the target color space to preserve the "look" over a wide variety of target, end color gamuts. This way you can do HDR, Rec 709 and other end products while preserving your artistic intent.

It's a bit more involved than this attempt at a simplified explanation, but that is it in a nutshell.

 

Edited by Frank Wylie
clarification
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Posted (edited)

You can use a standard keyboard and mouse just fine.

The big issue is having a graphics card with enough meat to do the top resolution you wish to export,a lot of very fast disk space and a good calibrated monitor at a bare minimum. 

The sofware maybe be free or cheap, but the hardware is NOT...

Edited by Frank Wylie
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Frank, Bruce, thank you for answers!

Bruce, 

9 hours ago, Bruce Greene said:

I have tried using the “auto” transform from a card in Resolve. Sometimes it works, other times, strange result and I don’t know why.

and what about smartphone "standard" footage? (just in case)

i.e. without LOG profile.

Is it technic applicable to this?...

(or, as I wrote - smartphone video is a totally crap?)

 

 

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You can use smartphone footage, as long as you can apply the proper image transform to translate it to the color gamut of the intended finished product.

Don't take this wrong but, first of all "standard" smartphone footage has absolutely no meaning.  You'll need to investigate your footage from the smart phone and determine exactly what codec was used to encode the video in order to use it properly when mixing it with other codec types (even of the same resolution).

Some smartphones have variable frame rates that cause huge problems if not recognized and addressed during post production.

Simply calling something "crap" without knowing why it won't work in the context you would like it to work, is a failure to do the hard work required to understand the limitations of your source footage.

The color calibration chip chart auto white balance routine in Resolve only addresses attempting to get the light in the scene to somewhere close to neutral color balance.  It does nothing to adjust frame rate or how the actual colors are going to react within the timeline if you are using the wrong color space.

Resolve is a complex, very versatile tool that can do wonders If you take the time to learn how to use it right.  This takes much time, effort and a desire to learn/retain.  If you put in the time, learn actually what is going on "under the hood", you will automatically know what you can and cannot do with mixed footage from various devices.

This doesn't mean that you have to sell all your possessions and enter a monastery for a decade to study the problem, but it does mean you need to dedicate the time and effort to understanding what the problem is at hand and to devote the time and effort to learn how to address those specific issues to arrive at a good product.

If you continue to do this as a matter of routine (assuming this is what you want to actually do for a living), then it will become automatic and your comfort and abilities with many forms of moving images and color spaces will grow with your experience and become a valuable tool.

 

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16 hours ago, Frank Wylie said:

You can use a standard keyboard and mouse just fine.

The big issue is having a graphics card with enough meat to do the top resolution you wish to export,a lot of very fast disk space and a good calibrated monitor at a bare minimum. 

The sofware maybe be free or cheap, but the hardware is NOT...

You can use a mouse, but the control will be coarse. Much finer adjustment is possible with a control panel. For serious work, the control panel is almost required for this reason.

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Bruce,

I'd agree if you are going to utilize the control surface on an ongoing and regular basis (i.e. professional).  However, in my opinion, the cost simply does not justify itself for casual use or even learning the fundamentals.  

It all depends on how serious the user is about color grading and how much of a budget you have to pursue the craft.  If you can't afford the panel, it shouldn't stop you from learning with a mouse and keyboard.

If I had to prioritize, a good monitor would come before the panel.  I don't have a panel on my home system, but then again, I don't grade outside of work for my living. YMMV.

Again, it all depends on your circumstances...

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