Matte vs mask vs key?

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teamnoir

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Matte vs mask vs key?

PostMon Feb 24, 2020 5:04 pm

What’s the difference?

Mathematically, I’m not seeing one, so I’m assuming it’s a subtlety I’m not yet grasping. Or maybe it’s just a tool specific distinction? When I google the topic, I get a bunch of tutorials about adobe.
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Tero Ahlfors

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 5:20 pm

It's basically the same thing but the difference is how it's made. With keying you key a color to make a selection, with a mask you mask the area you want and one could bring a matte from an external source (eg. a VFX dude) in and use that.
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teamnoir

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 6:07 pm

thank you.

So matte, (as in “matte box”), would be the opposite of masking? One selects by area while the other blocks what’s outside the selection? Same basic act, but different paradigms?
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Tero Ahlfors

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 6:18 pm

You should probably read chapter 112 on secondary qualifiers in the latest Resolve manual. It starts on page 2204.
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teamnoir

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 6:39 pm

Thanks. I've been through that stuff multiple times and I'm still getting nowhere. Too much jargon, too many assumptions, not enough actual explanation. Maybe I need to go hunt down some tutorials but I was hoping that clearing up some of the jargon might open it up to me.

If those are secondary qualifiers, what are the primary qualifiers? And what does anything on color page have to do with limiting how paint, on the fusion page, is applied?

I'm a computer engineer with decades of experience. The math is easy enough. I know what I want to do. I just can't figure out how to express that in resolve yet. But I appreciate the pointers, thanks.
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Frank Engel

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 6:51 pm

Matte is the traditional cinema (film) term.
Mask is the traditional still photography term.
Key is the traditional video/broadcast term.

These terms can be used interchangeably (they are the same thing) and as far as I can tell there is no real rhyme or reason as to which one Resolve (or Fusion for that matter) uses where, other than maybe the field from which a given use of the term originated or was more prevalent when the feature in question showed up?


As to qualifiers on the color page, those are not related to the Fusion page. Qualifiers are used to select a region of the image that the Color page tools for a selected node should have an effect on. As they are targeting only a portion of the image, this by definition is secondary color grading: a primary color grade impacts the entire image, a secondary grade only part(s) of the image.
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teamnoir

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Re: Matte vs mask vs key?

PostMon Feb 24, 2020 7:14 pm

Thank you.
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Marc Wielage

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Re: Matte vs mask vs key?

PostTue Feb 25, 2020 4:14 am

Note that you use the eyedropper tool while in Qualifier mode on the Color page, then use all the controls available to constrict, expand, or soften the selection. If you find the qualifier is grabbing too much extraneous information, you can use a garbage matte (aka Power Window) to only affect the information inside the window. If the subject moves, the window can track as needed.

All of this is covered in great detail in the manual and also in the Training Guides BMD provides for free:

https://www.blackmagicdesign.com/produc ... e/training

Bear in mind that learning Resolve is a process, not something you can just snap your fingers and do in a day. I've been keying in the program for 10-11 years now (and many other programs before that), and I still have to lean in and say, "wait a minute: I need to try this a different way." So there's no one method. Sometimes I'll key with a little NR, sometimes I'll add an OFX plug-in on top of that, sometimes I'll soften the key, sometimes I'll make the range very narrow. It's a very subjective area that heavily depends on source material.

What really gets complicated is when you have multiple keys going on, and then they cross in front of each other... and then you get into situations where the keys can't affect the other object and have to be masked out. This can get very involved.
marc wielage, csi • VP/color & workflow • chroma | hollywood
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teamnoir

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Re: Matte vs mask vs key?

PostTue Feb 25, 2020 8:14 pm

Thank you for the pointers to the training guides. If I ever knew they existed, I'd long since forgotten.

Time to do some research.
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teamnoir

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Re: Matte vs mask vs key?

PostWed Feb 26, 2020 7:11 pm

I've now spent a couple days going through tutorial videos, manuals, etc, and I'm still not getting it. I've learned a lot, but not what I wanted to know.

I'll ask in a separate thread.
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SantenPlu

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Re: Matte vs mask vs key?

PostFri Sep 03, 2021 12:58 pm

teamnoir wrote:I've now spent a couple days going through tutorial videos, manuals, etc, and I'm still not getting it. I've learned a lot, but not what I wanted to know.

I'll ask in a separate thread.


Did you came forward with this problem?
I found no way to ad AND remove power-windows to a qualifier.
In my case i need that for sky replacement with complex backgrounds using the alpha out.

I tried multiple ways with keymixer and the matte/mask options.
You can either ad OR remove something from a qualifier.

Thats very frustrating for such a simple task.
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SantenPlu

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Re: Matte vs mask vs key?

PostMon Dec 06, 2021 5:18 pm

any update?
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Andy Mees

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Re: Matte vs mask vs key?

PostMon Dec 06, 2021 7:57 pm

SantenPlu wrote:any update?
Not quite sure what you're waiting for an update on Santen? Using a qualifier to isolate an area of your image is pretty straightforward, adding a power window to constrain that qualifier to a specific region (ie remove everything else) is also very straightforward. If you then want to add another key region that may or may not also be qualified and/or defined by or constrained by another power window) then you could use a Parallel node to split the input source, qualify and/or isolate the second instance as needed, and then use a Key Mixer to combine the alphas from these two (or more) separate key sources you've created.

Take a look at Chapter 143, “Combining Keys and Using Mattes.” in the Reference Manual ... page 2892 is where it gets in to adding and subtracting keys.
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Marc Wielage

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Re: Matte vs mask vs key?

PostTue Dec 07, 2021 12:32 am

Andy Mees wrote:Take a look at Chapter 143, “Combining Keys and Using Mattes.” in the Reference Manual ... page 2892 is where it gets in to adding and subtracting keys.

That is hugely important. The trick is (I almost said "the key is") to figure out a way to constrain and control the key so that only what you want to control will be affected by the key. I tend to think of a MATTE as everything "inside" the window that I'm actually keying, and a MASK (aka a garbage matte) is everything "outside" that I'm trying to avoid changing. Sometimes you need to use multiple windows, like in a case where you've got a shape around one character and another person walks in front of them. That requires animating and tracking a mask on that person, in the same node, in mask mode so that the key doesn't affect them.

There are good video tutorials that explain the basics of keying and masks in great detail: I often recommend Ripple Training, Mixing Light, and FXPHD as being great resources to anybody using Resolve, new and old. And Lowepost, TACResolve, and De-Mystify Color also have some additional training ideas that are helpful. Cullen Kelly and Darren Mostyn on YouTube have some great free tutorials as well. All of them cover keying and masks/windows in great detail.

Hey, if you think keying/masking in Resolve is difficult now, you should've seen it 20 years ago: it was a nightmare with daVinci 2K (the predecessor of Resolve). That was very tough. From 2008 on, DaVinci Resolve became much more streamlined and understandable, so what we have now in 2021 represents literally decades of thought on how to make operations like this easy and accessible, and not so cryptic and weird. Once you know what you're doing, it takes maybe 10-15 seconds to set one of these up.
marc wielage, csi • VP/color & workflow • chroma | hollywood
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TCP786

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Re: Matte vs mask vs key?

PostTue Dec 07, 2021 2:02 am

Marc Wielage wrote:The trick is (I almost said "the key is")
Excellent.
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Peter Cave

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Re: Matte vs mask vs key?

PostTue Dec 07, 2021 4:18 am

Think of those words as processes rather than functions.

Keying is the action that creates a matte which cuts the hole for the video to show through.
The Foreground, Background and Matte can all be Masked by another tool such as a Garbage Matte.

You will find people often use the wrong term.
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Marc Wielage

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Re: Matte vs mask vs key?

PostTue Dec 07, 2021 6:38 am

Peter Cave wrote:Keying is the action that creates a matte which cuts the hole for the video to show through. The Foreground, Background and Matte can all be Masked by another tool such as a Garbage Matte.

Yeah, we'd often use the phrase "cutting the hole" for the key in the 1970s and 1980s, so that was a thing. That was in the days of the video switcher, where you had to figure this stuff out with "live" images (or in my cases, images from film or videotape) and you had to key titles or other information for the show. We also had an Ultimatte keyer in the room for green screen material, and we'd do them "live" by pulling in a background image from tape and then adding the foreground image from film through the Ultimatte... which was essentially an early 3D keyer. I still have PTSD from doing Ultimattes for the old Muppet Babies TV show, which was a heavy user of that process. That was all done on DaVinci Renaissance, the ancient 1994 ancestor of daVinci Resolve.

Image

We did have to carefully garbage matte stuff so just the inside of the door would be keyed and not Gonzo (blue) or Kermit (green). Quite a technical nightmare, but a very entertaining show. It's a thousand times easier and more precise to do it nowadays.

I believe Blackmagic bought the rights to Ultimatte some years ago and still has a standalone chromakeyer available for live TV:

https://www.blackmagicdesign.com/products/ultimatte

I would venture to guess that some of the concepts from Ultimatte exist in Resolve today.
marc wielage, csi • VP/color & workflow • chroma | hollywood

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