Basic Color Grading Steps for D-Cinelike

[Gryphon962]

Hi,

I'm about one month in to my first drone (MP) and I'm trying to learn as much as i can about post-processing of images (and eventually video) to get optimal results. After a lot of youtube advice I settled on D-Cinelike +1-1-1 for all the good reasons you hear about on youtube (and in here). I'm using GIMP to post-process my images. I've watched a lot of tutorials and understand that because of the limitations of the 8 bit sensor in the MP, D-Cinelike is not a true 'log' capability but it gets acceptable results out the camera and will improve a lot more than the other styles (except D-Log) when post processed.

So the fundamental question that remains after many youtube vids is: what are the generic corrections needed to any D-Cinelike image that should result in an image that is ready for final tweaks?

My experiments in GIMP show that in the Curves view my image usually fits within 5% - 92% of the histogram range, so by adjusting the Curve to those values I get the image to lose a lot of its flatness and the contrast pops right out. Did I get those numbers right? Do I need to also lift or drop the mid-tones by a few percent? I'm guessing yes, but its tough to figure out how much in general.

The image also needs more saturation - I find that raising that from 1.0 to somewhere in 1.14 - 1.20 range seems about right. Thoughts?

Hardest part for me is Color Balance - does D-Cinelike intrinsically alter the color balance such that there is a standard tweak needed in post? I'm guessing a small lift in red is needed, but welcome opinions.

Now, I know that everyone has a LUT to sell or give away, but I want to learn. I have tried a gazillion LUTS (in G'MC QT plugin) but only about 3 of the hundreds in there seem to do the right things to a D-Cinelike image. Advise welcome, but I'm not looking for 'use this LUT' answers unless I understand what the LUT is actually doing in terms of levels, saturation, balance, etc.

 

[Drone on]

Hi,

I'm about one month in to my first drone (MP) and I'm trying to learn as much as i can about post-processing of images (and eventually video) to get optimal results. After a lot of youtube advice I settled on D-Cinelike +1-1-1 for all the good reasons you hear about on youtube (and in here). I'm using GIMP to post-process my images. I've watched a lot of tutorials and understand that because of the limitations of the 8 bit sensor in the MP, D-Cinelike is not a true 'log' capability but it gets acceptable results out the camera and will improve a lot more than the other styles (except D-Log) when post processed.

So the fundamental question that remains after many youtube vids is: what are the generic corrections needed to any D-Cinelike image that should result in an image that is ready for final tweaks?

My experiments in GIMP show that in the Curves view my image usually fits within 5% - 92% of the histogram range, so by adjusting the Curve to those values I get the image to lose a lot of its flatness and the contrast pops right out. Did I get those numbers right? Do I need to also lift or drop the mid-tones by a few percent? I'm guessing yes, but its tough to figure out how much in general.

The image also needs more saturation - I find that raising that from 1.0 to somewhere in 1.14 - 1.20 range seems about right. Thoughts?

Hardest part for me is Color Balance - does D-Cinelike intrinsically alter the color balance such that there is a standard tweak needed in post? I'm guessing a small lift in red is needed, but welcome opinions.

Now, I know that everyone has a LUT to sell or give away, but I want to learn. I have tried a gazillion LUTS (in G'MC QT plugin) but only about 3 of the hundreds in there seem to do the right things to a D-Cinelike image. Advise welcome, but I'm not looking for 'use this LUT' answers unless I understand what the LUT is actually doing in terms of levels, saturation, balance, etc.

My understanding is that D-Cine is a color profile not unlike a Lut.
Regardless, what has to happen first is color correction such that what s/b white is white. The problem is not much in an aerial view is white, and if you fly in civil twilight, or the golden hour what is white should not be white. Instead, at these times, what is white should appear somewhat blue in the shadows, or golden in the sunlight; respectively.
So, what I do is balance the RGB as best I can. After that, I tweak the contrast, and saturation to get a look I like.
At the same time of the workflow, or at a time that suits you best, you want to bring your blacks as far as possible and your whites up as far as possible, then tweak the mid range through curves.
Each video is different. Some come out naturally darker, and any attempt to brighten them will impact the overall appearance, and vice versa.
My experience with DJI video is that the presets of Sunny and Cloudy are higher on the Kelvin scale than I like. So, I use the custom kelvin meter to dial in a look based on the situation. I tend more toward cool, but pay attention such that red things don't go purple, and sidewalks still look warm when they're supposed to be. Typically, I start at 5600 kelvin and adjust from there.
It's an art.
If you get good at it, you can sell your own luts.
Some people strive for a dry look not unlike D-Cinelike, others work toward a heavily saturated look. I liken the first to artsy cinema, and the latter TV

 

[Gryphon962]

Regardless, what has to happen first is color correction such that what s/b white is white. The problem is not much in an aerial view is white, and if you fly in civil twilight, or the golden hour what is white should not be white. Instead, at these times, what is white should appear somewhat blue in the shadows, or golden in the sunlight; respectively.

If I understand you correctly, the final image should show white in the 'true' color temp for the light at the time. However, I'm not sure that color temp is changed by the use of the D-Cinelike filter (unlike the other tweaks to contrast, saturation, etc). Thinking about that convinced me that unless anyone knows the actual parameters that went into the creation of the D-Cinelike filter, it should be possible to reverse engineer it by taking two images of a scene, one in D-Cinelike and the other in either 'None' or 'Truecolor', then in post figure out what tweaks are needed to change the D-Cinelike image to match one of the others.

If that sounds like a plan, which filter is more consistent with the eye, and therefore useful as a baseline: None, or Truecolor?

 

[Drone on]

If I understand you correctly, the final image should show white in the 'true' color temp for the light at the time. However, I'm not sure that color temp is changed by the use of the D-Cinelike filter (unlike the other tweaks to contrast, saturation, etc). Thinking about that convinced me that unless anyone knows the actual parameters that went into the creation of the D-Cinelike filter, it should be possible to reverse engineer it by taking two images of a scene, one in D-Cinelike and the other in either 'None' or 'Truecolor', then in post figure out what tweaks are needed to change the D-Cinelike image to match one of the others.

If that sounds like a plan, which filter is more consistent with the eye, and therefore useful as a baseline: None, or Truecolor?

good question.

A polarizer will reduce glare, and increase saturation, but not necessarily 'filter' to 'true' colors. The next challenge is various monitors, various eye sight...my brother in law can't see the color green, various tastes/sophistication, etc...

To me ND filters tend to tint images amber

I believe both None, and Truecolor are also presets.

Studying photography/videography, I've learned that equipment manufactures differentiate themselves by their applied color science through the processor, so all equipment is preset.

Film from film cameras/video recorders is also a preset. The net effect is affected by the amount, sensitivity, and quality attributes of the emulsion applied to the actual film backing that becomes what is developed. To complicate, or at least non standardize matters further, the light recorded on the film is further affected by the quality of glass the light is received through.

A scientific approach can be challenging, when in the end, it is subject to taste; therefore an art.

 

[Gryphon962]

I've read that Rec709 seems to be a baseline style. Does anyone know if 'None' or 'Truecolor' are same or close to that?