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Old December 16th, 2009, 08:49 PM   #1
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what's better for post low chroma or high?

There's been alot of talk here about the pro's ad cons of shooting low con and low sat for grading or trying to achieve a final look while shooting. I'd like the technical people here to weigh in on a question central to that discussion:

For post is it better to shoot low chroma and add more saturation afterwards or better to have a little too much and reduce it grading? Obviously getting it right the first time would be ideal, but if you are going to err - which direction is better?

Off hand I would guess too much is better , but I am just guessing.
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Old December 16th, 2009, 09:09 PM   #2
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If you are going to err, err on the side of not enough. There are a ton of caveats to this though.

Traditionally, formats like film and RAW (Arri, RED, Genesis, Viper, etc.) create a very "flat" image when captured. It is very easy to move this kind of footage around, change the apparent time of day, accentuate certain colors, or reduce others, etc. BUT, these formats have infinitely more information embedded in them than the highly compressed formats most of us work in.

So when we reduce chroma in the camera, we aren't really doing ourselves any huge favors if we are later just going to push those colors right back up. We are simply adding gain in the color channels and that's not all that helpful.

However, this situation is FAR preferable to color clipping. It's just like recording an image that is too dark. We can push up the gain and get the image as bright as we want, but we bring the noise with us. However, if we clip the image then there's no saving it. Color works the same way. If we oversaturate the colors that is not fixable in post. So it's preferable to have not quite enough color than too much.

I tend to shoot a lot of my footage very flat. I realize that shooting that way really is going to introduce some color noise. I am willing to live with that for the flexibility of coloring in post the way I want. Not everyone would be willing to do that. So you take the trade-offs either way.
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Old December 16th, 2009, 10:03 PM   #3
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just like the Lumenescence , if you shoot to low , you can crank it up, but if you shoot to high its clipped off the top and gone forever.
and when they shoot to low, i hate it, like say 50% IRE, because cranking it up the range is gone, if i had 256 possible locations for the luminescence mr. to low cameraperson now cut me off to 128 steps already. magically recreating the other 128 doesnt happen.
so IMO you dont shoot lumenescence to Low OR to high.
i dont want a post gained up mess anymore than i want excessive white clipping.

with color
what does the camera originally deliver (default) Because SOMEWHERE i will be processing it , before compression codec or after? i think i would prefer before
i dont want it to high and not having a range because its (say) only 128 red steps because of oversaturation.
i dont want it to Low, because if it isnt THERE i cant magically recreate it.

i want to SEE the color HOT HOT HOT, i crank up the viewer at Least, so i can see any offset white balance or colorations , because fixing that stuff in post doesnt work like it should/could , if the colors are screwed up its a mess to get it back, if at all.
if the saturation is so low i am not seeing any of it's major tint problems, or color offsets then i went off blind , and made an irreperable mess.

i dont want to control it all the time in the Feild, especially if i am going to have to process it anyways. the freaking camera should be able to deliver a consistant proper saturation, neither to high or to low, with the human setting temperatures , white balance and controlling lightings and such.

if i dont have to post process it from totally correct original, then i might not have to de-re-compress the signal At ALL ever (in my dreams), except to put it on the output format, and the storage format is also cleaner less de-re-compressed image.

i want it all perfect , the first time , and i expect the camera to at least assist in the adventure. do it right, or go home :-)
Are these thing that hard to control now? minus the 500 menu settings to reek havoc on the internal processing?
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Old December 16th, 2009, 10:34 PM   #4
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Thanks Perone,

You might be talking about a more extreme situartion than I was thinking about though.

How far does your color need to go to create "color clipping". I'm not talking about and extremely saturated picture, just something perhaps a bit rich that you might turn down a touch in post. I realize that anything way over-saturated would be destructive. For example I don't think shooting in say std 3 with the matrixes all at 0 and using High Sat tends to a extremely over-saturated picture that would be clipping would it?

It sounds like you are acknowledging that adding color to a flat picture does add a bit of noise. Aside from clipping is there any other negative to shooting a "rich" picture and turning down later?

Without testing - so I'm guessing here - it would seem to me that you would want to have enough information from each of the colors so that if you want to alter it there will be something there to pull up.

I've always noticed that when chroma is low - either in the monitor or the camera itself, when in situations where you can adjust lighting or can cheat white balance - there is a common tendency to want to warm up what seems like a dull image and thus end up with something that is pushed way too much to the CTO side of things. I think that's what Marty was talking about.
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Old December 16th, 2009, 11:18 PM   #5
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A lot depends on the camera. 8-bit color (at best) isn't a whole lot of space. Point your handycam at the sky on a cloudless day, and you'll get to see the colors break.

I liken the idea of grading from a flat image vs grading from a well saturated one as akin to coming to a fork in the road. If we choose a direction, then check the map 1 minute later, we can verify we are on the right road. If we chose incorrectly, it's easy to back up and go the other way. If we chose correctly, then all is well.

Let's say we go to shoot a scene for a movie. We are out in a hayfield and it's 10am. Bright sunny day, not a cloud in the sy. We finish all but a few lines because the DP says we've lost the sun. We decide to complete the scene the next day. The next moring is overcast, flat, and gray. How do we seamlessly combine the two days?

If we shot day one with full, rich color and strong contrast, you're done. If you shot it fairly low contrast and somewhat flat, you can get a reasonable match.

I am catching hell right now trying to do a color grade on a short film, where the lighting was changed on an indoor scene, and it was shot to look good out of the camera, even though everyone KNEW we were going to do an extensive post. I am trying to invent lights in post, get shadows to match, get skin tones to match etc. Biggest pain in the neck in the world.

So in "perfect world", yes, shoot everything with rich, bright colors and nice contrast. Nothing will ever go wrong, footage will never get corrupt, there will never be a need for a reshoot at a different but similar location on a similar but different day. In the REAL world, this kind of thing happens all the time.
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Old December 16th, 2009, 11:35 PM   #6
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thats good
i could compare that to Scanning Pictures with a scanner.
The scanner software has all sorts of processing TRICKS that it can do to the scanned image, they often work ok , but if you really want the RAW unretouched scan that comes off the scanner imager, you have to turn all that junk OFF.

you get this flatter, less contrasty, less sharpened, uncorrected image thing that looks pretty bad , dull, lifeless.

load that up into Photoshop and you can do anything with it, no attempt yet has been made to do the auto corrections stuff.

because that is ALL the imager was giving the software anyway.

The software would try doing all its cheap tricks in its semi-automatic mode, and it isnt as controlled for EACH picture as well as, the human could do to it manually.

the only difference here is we already are going to turn it into a low bit rate compressed picture for storage. :-) THEN load it back in for processing.
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Old December 17th, 2009, 10:30 AM   #7
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Thanks Perrone,

That's very interesting and the opposite of what I expected. I guess I'll have to do some tests of my own.

If you have any images that illustrate what you're talking about I'd love to see them.
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Old December 17th, 2009, 10:41 AM   #8
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Thanks Perrone,

That's very interesting and the opposite of what I expected. I guess I'll have to do some tests of my own.

If you have any images that illustrate what you're talking about I'd love to see them.
YouTube - Fountain_cut1_Ungraded_SD.mp4

YouTube - Fountain Cut1 Graded HD

I've done some other examples, but don't have any handy at the moment.
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Old December 17th, 2009, 11:43 AM   #9
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wow that must have cost a few bucks to use Billy's music?
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Old December 17th, 2009, 11:49 AM   #10
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wow that must have cost a few bucks to use Billy's music?
We're tight like that...

It was supposed to go up and come off. I really need to replace that music... in fact, I'll do it now. Thanks.
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Old December 17th, 2009, 01:11 PM   #11
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Perrone,
To be honest that sample doesn't convince me as to me it looks like what I might guess would happen from a low sat original.
I don't mean to criticize how you colorized the shot - that's fine and it belongs inside a sequence of some kind anyway.
But I do notice that individual colors don't have a lot of their own contrasting saturation.

It looks like to get saturation back into the red stones you've had to add warmth into everything including the whites of the water and especially the sky and the lamp. Of course its a warm late afternoon look , but it looks like the original had a slightly blue sky. Even the foreground blues look like they've lost some of the purer blue quality ( did you use a warm grad)

Its moody and probably what you wanted, but doesn't have a lot of pop to the color. Could you have added color in a way that would have created more pop ( without taking the time for secondary color corrections?

My guess is that had the original more saturation you could have gotten maybe the same mood, though perhaps the mood would have been harder.

Actually it looks like an extreme example - do you always shoot with so little saturation.

On a related note isn't it easier to grab colors for a secondary color correction if you already have more saturation.
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Old December 17th, 2009, 01:55 PM   #12
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Perrone,
To be honest that sample doesn't convince me as to me it looks like what I might guess would happen from a low sat original.
I don't mean to criticize how you colorized the shot - that's fine and it belongs inside a sequence of some kind anyway.
But I do notice that individual colors don't have a lot of their own contrasting saturation.

It looks like to get saturation back into the red stones you've had to add warmth into everything including the whites of the water and especially the sky and the lamp. Of course its a warm late afternoon look , but it looks like the original had a slightly blue sky. Even the foreground blues look like they've lost some of the purer blue quality ( did you use a warm grad)

Its moody and probably what you wanted, but doesn't have a lot of pop to the color. Could you have added color in a way that would have created more pop ( without taking the time for secondary color corrections?

My guess is that had the original more saturation you could have gotten maybe the same mood, though perhaps the mood would have been harder.

Actually it looks like an extreme example - do you always shoot with so little saturation.

On a related note isn't it easier to grab colors for a secondary color correction if you already have more saturation.
It was an extreme example. I'll have to work on getting you something more "normal". Give me a few minutes to work something up.
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Old December 17th, 2009, 02:22 PM   #13
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Let's try this instead.

The original image is not mine. It was downloaded from Cinematography.net as a RAW Viper image as a DPX.

What we have are the original, and 3 processes of work that I did to it.

1. Original
2. Contrast correction with 1-light color pass (aka white balance)
3. Color correction with 3-wheel color corrector
4. Saturation added, color tweaked, output set of computer RGB for showing online.

From here, someone would then do a color grade to match other footage or impart a "look". The idea here was simply to get back to "normal". And since I have no color reference I am absolutely guessing at what the scene might have looked like.
Attached Thumbnails
what's better for post low chroma or high?-londoneye_raw.png   what's better for post low chroma or high?-londoneye__contrast_1color.png  

what's better for post low chroma or high?-londoneye__contrast_colorcorrected.png   what's better for post low chroma or high?-londoneye_final.png  

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Old December 17th, 2009, 02:36 PM   #14
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Better yes,
But it feels to me I'm still not seeing much color in the city or the river. Still doesn't pop to me. That might be just the effects of haze, and it might be appropriate for the shot, but could it also be the result of a low chroma original?
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Old December 17th, 2009, 02:49 PM   #15
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Better yes,
But it feels to me I'm still not seeing much color in the city or the river. Still doesn't pop to me. That might be just the effects of haze, and it might be appropriate for the shot, but could it also be the result of a low chroma original?
Pop? Dude they're a half-a-mile up! Of course it's not going to pop. Have you kooked at a photo of London even on the ground?!

I've got another one coming with more color...
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