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Old 26th June 2018, 21:24   #14  |  Link
WorBry
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Quote:
Originally Posted by WorBry View Post

Moving on to the remaining two test clips, similar considerations apply to GOPR0201 where we again have patches of skylight flooding in from above...

....So far I've managed to come up with some quite nice grades in Resolve using the Channel Mixer and Primary Color wheels, coupled with 'soft-clips' applied to the individual RGB channels for fine tuning of the highlights and shadows - and without recourse to 'qualifiers'
Examples:

Original GOPR0201 clip:



Pre-denoised (SMDegrain) and graded in Resolve using just the RGB Channel Mixer for setting the color balance - 'skylight' used as the neutral reference. And then the usual levels/contrast adjustment, mid-tone detail' (local contrast) and sharpening:




Same initial channel mix followed by some secondary manipulations with the color wheels to shift the bias to warmer tones at the lower depths:



A 'soft clip' applied to the Red channel helped to preserve the cooler neutral balance of the skylight. Also applied some lift in the shadows (without raising the black point) to bring out more detail - Resolve has a tool specifically for that. Plus the usual contrast, mid-tone detail, sharpening.

A lot better I think. Brings the coral to life.

Replicating the grade in Vdub2 with Channel Mixer + RGB curves is proving more tricky. Very difficult to achieve smooth transition of hues in the sea background, especially when saturation (which it needs) and a little contrast are added. Here's a preliminary result using only linear shifts in the R,G and B curve gradients (no soft clipping) and no added saturation or contrast. Very much work in progress:



The color balance per se holds up reasonably well over the entire clip, but I think it would need dynamic adjustment of levels (and saturation) at key points - just the job for 'Master Blend'.

If you want to play with it, the settings were, in sequence:

Source: Original clip pre-denoised (SMDegrain)

*Channel Mixer:

RR 71.68%
RG 101.76%
RB -58.69%

GR 10.55%
GG 90.72%
GB 0%

BR -11.52%
BG 7.52%
BB 101.76%

*RGB Gradation Curves:

Mode: RGB Weighted + R/G/B

Red:
In/Out
0,7
255,235

Green:
In/Out
10,0
255,255

Blue:
In/Out
28,0
247,255 (Keeps a slight cool bias on the 'skylight' )

*Levels:
In: 32,255
Out:0,255

*UnSharp Mask:

Radius: 1.6
Strength: 1.09
Threshold: 0

Edit: I guess it's not too bad 'as-is' with added saturation. Here Saturation +1.4 with the '6-axis corrector' placed between the RGB Curves and Levels in the sequence.



As you can see though, it brings out more green hues around the margins of the 'skylight'. Needs some fine re-tweaking of the color balance.

Edit: Alternatively, could be done using 'RGB Levels' filter in place of RGB Curves:



So, there:

*Channel Mixer: As above

*Levels:

In: 0, 1.080, 255
Out: 12, 234

*RGB Levels:

Red: 0.14, 0.985
Green: 0.213, 0.923
Blue: 0.246, 0.95


*Unsharp Mask - as above

It would benefit from a 'soft clip' instead of 'hard clip' on the Red channel highlights, but it's OK.


Edit: And the last remaining test clip GOPR0233.

Original:



Corrected with VDub2 using the same process - Channel Mixer > Levels > RGB levels, plus (in this case) some added contrast and saturation, and the usual sharpening:



I think that combination works rather well. Process settings in that case were:

Source: Original clip pre-denoised (SMDegrain)

*Channel Mixer:

RR 53.61%
RG 164.94%
RB -73.73%

GR 10.55%
GG 98.73%
GB 0

BR -28.61%
BG 18.55%
BB 83.69%

*Levels:
Input: 20, 1.080, 255
Output: 0,255

*RGB Levels:
Kept a slight blue bias on the 'skylight'

Red: 0.13, 0.95
Green: 0.194, 0.921
Blue: 0.241, 0.926

*RGB Gradation Curves (for centre-relative contrast):

Mode: RGB Adjusted
Coordinates:

In/Out
0,0
64,57
128,128,
192,196
255,255

*'6-Axis Corrector' (for Saturation only) + 1.461

*Unsharp Mask:

Radius: 1.6
Strength: 1.09
Threshold: 0
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Last edited by WorBry; 28th June 2018 at 16:47.
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