[Liverpool] Advice on colour correcting scuba diving images and videos

[Andrew Back]

I can confirm DaVinci Resolve is great for colour correction, which is
its primary function and the addition of an NLE came much later in its
history. You do need a half-decent GPU, though.

Helps if you shoot in log format, which looks washed out unprocessed,
but preserves all the dynamic range in the sensor, rather than
processing on-camera to make it look "normal". That way you have more to
play with when correcting in post. The setting is sometimes labelled "film".

Getting a base correction is much easier if you have a shot of a
colourchecker card, as there is a tool in Resolve where you just drag a
grid over the frame, click a button and the process is automated. There
is an auto colour correction function that attempts it without this, but
results can be highly variable. Not sure if anyone does underwater ones!

Mastering colour correction is a real skill / art form, but with a bit
of reading up and a basic understanding of what to look out for when
fiddling with lift, gamma and gain etc. — mainly losing details in
shadows, mid or highlights, else just looking in some way pretty bizarre
— you can often get some good improvements without having to learn all
the various tools and complex multi-node corrections.

Resolve is not F/OSS, obviously, but gratis and this is not bad
considering it seemingly once cost something like $15-20K/seat.

Could be worth a look at OpenCine, but last time I checked it was very
much an early alpha.

  https://wiki.apertus.org/index.php/OpenCine

Cheers,

Andrew

On 27/08/18 11:01, Tom Ormiston via Liverpool wrote:
>
> Hi Alex,
>
> Kdenlive is good but the GPU rendering isn't sorted yet (same for
> Shotcut) so it can be slow to render videos. It all depends on what
> your doing.
>
> Lightworks video editor is not open source but there is a free version
> (720p)
>
> If its just video (no sound - your under water?) you might want to try
> Natron https://natrongithub.github.io/
>
> Its specifically designed for Hollywood level video composition.
>
> There are also many plug-ins, a quick search I came up with
> https://github.com/NatronVFX/natron-plugins
>
> Checkout
> https://opensource.com/article/18/4/new-state-video-editing-linux for
> some Linux based video editing info
>
>
> For Photographic work then Darktable is excellent (though for best
> results, RAW image format)
> Have a look at https://opensource.com/alternatives/adobe-lightroom and
> 'Keifer Hunniford Photography' or Shane Milton on youtube
>
> cheers,
> Tom Ormiston
>
> On 27/08/18 09:10, Alex Lennon via Liverpool wrote:
>> Hi all,
>>
>> Apologies for the cross-post but I thought the LivLug group would
>> likely have some insights here too ...
>>
>> I have a number of pictures and videos I've taken on dives at a depth
>> of 10m-20m. As you'll know you lose components of the visible light
>> spectrum as you go deeper underwater, initially red etc.
>>
>> There are various strategies to improve the pictures you take
>> underwater (strobe lighting, white balance correction) and there is
>> post-processing that can be done to improve the images.
>>
>> I've tried all sorts of tools but it very quickly seems to get
>> complicated and I can't seem to crack it.
>>
>> KDenLive looks good (opensource) and a friend recommended DaVinci
>> Resolve which also looks interesting.
>>
>> Does anybody have the time and interest to give me some advice on how
>> to drive a tool to improve the colour balance of my media?
>>
>> Thanks!
>>
>> Alex
>>
>>
>
>
>

-- 
Andrew Back
http://abopen.com

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