You dropped a LUT on your footage and it looks bad. Too contrasty, or washed out, or
the skin has gone orange. Before you conclude the LUT is rubbish, it is worth knowing
that in almost every case the LUT is doing exactly what it was built to do, to footage it
was not built for.
Here are the five causes, roughly in order of how often they turn up.
1. You applied two conversions
Looks like: heavily crushed blacks, blown highlights, colours that
are far too strong.
Your editor detected the log format and applied a conversion automatically, then you
applied one as well. Both are doing the same job and the effect doubles.
In Final Cut, check the Camera LUT dropdown in the clip inspector. In Resolve, check
whether a LUT is set on the clip attributes or in the colour management settings. In
Premiere, check the Input LUT slot under Basic Correction before you look anywhere
else.
2. You applied a look without converting first
Looks like: flat, grey, lifeless, as though the LUT barely did
anything.
Creative LUTs are built to sit on top of a Rec.709 image. Put one directly on raw log
footage and it has nothing to work with, because the image it expects has not arrived
yet.
The order is conversion first, then corrections, then look. Not look first. We wrote
about what a conversion LUT actually does
here.
3. The footage was underexposed
Looks like: noisy shadows, thin muddy colour, an image that falls
apart the moment you push it.
This is the one nobody wants to hear. Log holds detail in the shadows, and a
conversion lifts those shadows back up. If there was noise down there, the conversion
lifts the noise too.
Most log formats want you to expose brighter than looks natural on the monitor. If
your footage is consistently disappointing after conversion, the fix is at the camera,
not in the edit.
4. Wrong log format for the LUT
Looks like: nearly right, but the contrast is off and the colours are
slightly wrong in a way you cannot name.
An S-Log3 conversion applied to S-Log2 will not throw an error. It will just be
subtly incorrect everywhere. The same happens with D-Log versus D-Log M, C-Log2 versus
C-Log3, and Apple Log versus Apple Log 2.
Check what the camera actually recorded rather than what you assume it recorded. Many
cameras change the default between firmware versions.
5. The LUT is fine and the shot is difficult
Looks like: everything is technically correct and it still does not
sing.
A LUT is a starting point, not a finish. Mixed colour temperature, a bad white
balance, or a scene with no contrast in it will not be rescued by any look. Fix white
balance and exposure first, get to a neutral image you would be happy with as it is, then
apply the look.
If a look only ever works at forty percent strength, that is usually a sign the image
underneath is not neutral yet.
The quick check
Turn the LUT off. Look at the image. If the raw converted footage is already noisy,
badly exposed or oddly coloured, no LUT will fix that, and you have learned where the
real problem is.
If you want to test a clean conversion on your own material before buying anything,
our conversion LUTs are free for fifteen cameras.