Blackmagic Forum

Is there a way to see the settings embedded in a LUT?

I work in Ecommerce, we have a standardised LUT we put over the top of the our videos. It puts saturation back into the image, skintone, clothing etc.

Over time however and multiple small tweaks the LUT reacts badly to certain colours. Its been passed between different colourists, plus we've adjusted for light changes.

I'd like to see what the main adjustments are, replicate them, and throw out the smaller issues.

I've got quite close but I can't seem to hit the bullseye.

Any help would be grand. Apologies if its terribly obvious and it's wasting peoples time. Nerd wrath kept to a minimum is better for everyone.

Text editor will work. You will need to understand the format and how it works as it is just a list of numbers.

patrickwilson wrote:I work in Ecommerce, we have a standardised LUT we put over the top of the our videos. It puts saturation back into the image, skintone, clothing etc.

I think this is a very bad idea. You would be much better off actually hiring a colorist to solve these problems shot-by-shot, scene-by-scene, and day-by-day. Shooting conditions always change: exposure, lenses, lighting, color temperature, all kinds of stuff. A LUT is not the answer for these problems.

Don't put your faith in LUTs. Put your faith in tools like Resolve, plus scopes and a great monitor you can believe in. This would be as hopeless as having a black box that adjusted the level for (say) a male singer, and then thinking it would work for a female singer, or a child, or a person speaking, or a person yelling, or an opera singer, or a rock & roll singer. Each one of those requires a different approach: different EQ, different compression, sometimes a different microphone.

Or as an old mentor told me many years ago: that's why the knobs move.

To be clear:

We're not filming in conditions that alter.
None of the settings are different between shots.
We film in a studio where nothing changes.
Above all, consistency is important.

I need to recreate a LUT I've inherited.
I've got close.
But I'd like to preview the old LUT to ensure I've covered all bases.

Does this make sense?

It's like an action in photoshop where you can see and alter the step by step process - Can I see this in Da Vinci? It looks like a no, but I thought I would ask.

put the same shot on the timeline twice and lut a on one clip and lut b on the other.
split screen or mix to see the difference.
You can look at monitor, scopes, histogram.

You could also put the clips one over the other, and use the difference composite mode.

In each case, adjusting your new lut to match will need grading or color science expertise, or both.

Imho you shoudn't "play" with LUTs this way, but make relevant powergrades instead, which you could "apply" or "append to" the last node... This WF may be more suitable to your needs.

Sam Steti wrote:Imho you shoudn't "play" with LUTs this way, but make relevant powergrades instead, which you could "apply" or "append to" the last node... This WF may be more suitable to your needs.

PowerGrades are fantastic and I use them all the time. When you're just dealing with one or two nodes, they can be very useful and can be used in multiple projects, shots, and circumstances. LUTs... not so much.

A look up table is just a bunch of numbers, theres no real way of seeing how it was made. Sorry if I am assuming you mis-understand what a LUT is but open it up in something like text edit and see for yourself.

You could use a program like lattice to view it in various ways, but your best bet is to eye match it as close as possible like the others have suggested.

Then save it as a power grade and use that instead.