[Bf-compositor] Clamping (Mix, Math, RGB Curves)

Sean Kennedy mack_dadd2 at hotmail.com
Thu Jun 5 21:30:16 CEST 2014


I set up a node that works great. RGB Curves worked better than Color Ramp, but I didn't want to use drivers to control the values. Sergey, genius that he is, made a simple node tree that recreates how the curves tool works, and I incorporated that into the node I wanted to make. Thanks, Sergey!!!!
I call it Christiansen_CC, because I learned the technique from Mark Christiansen, but of course you can call it whatever you want.

Here's the node itself, if anyone wants to try it. https://dl.dropboxusercontent.com/u/10553822/mark_christiansen_CC_match_node_final_01.zip
And here's a quick little demo video.https://dl.dropboxusercontent.com/u/10553822/Christiansen_CC_demo_01.mp4
Please don't' share it publicly, I have no rights to publish the images I used in the demo.
Sean

From: f.paglia.80 at gmail.com
Date: Wed, 28 May 2014 19:48:18 +0200
To: bf-compositor at blender.org
Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)

I tried this datapath too... could you tell me which release of blender are you using?
 

2014-05-28 19:27 GMT+02:00 Diego Gangl <dnicolas at gmail.com>:


It's working for me, but Blender gave me a different datapath:

nodes["RGB"].outputs[0].default_value[0] .

If I change it the 0 to RGBA I get an error too. I guess you can't use

dictionaries for sockets in drivers?



2014-05-28 9:15 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:

> Hey Diego,

> I successfully added the driver,

> I got the problem in the path of the RGB..

> Here the picture I made to explain the problem:

>

> https://lh6.googleusercontent.com/-k6GDiWl4uNU/U4XRy1AzQ_I/AAAAAAAAJy8/C-xuqUDrNKM/w1357-h784-no/value.jpg



>

> I forgot to open the panel in the left of the drivers ..

>  I'm working on the red channel of the ramp and I was trying to evaluate the

> red value of the RGB node that is perfectly showed in the python console but

> as you can see return a red background on the path of the driver....

>

> Am I missing something?

>

>

>

>

> 2014-05-28 13:15 GMT+02:00 Diego Gangl <dnicolas at gmail.com>:

>

>> Hey,

>>

>> Nice work on those nodegroups, I'd like to see them too. It would be

>> great to have some kind of standard library of nodes for motion/video

>> work in the compositor with stuff like this.

>>

>> Francesco,

>> Have you tried the outliner workaround for problem #2? You'd have to

>> find the node in the outliner, then the socket, select it and press D

>> to add the driver. Btw, it doesn't change color in the ui sometimes.

>>

>> I tried the nodes addon but I get a missing paths error, maybe it

>> hasn't been updated?

>>

>> Cheers,

>>

>> 2014-05-28 7:15 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:

>> > Hey Sean,

>> > I'm really interested in seeing your node and much more on the match

>> > color

>> > node...

>> > I've tried by myself making one but I couldn't find a nice way to have

>> > the

>> > setup embedded in a node group.

>> >

>> > Looking at the tutorial the artist simply match low and hi valuse of a

>> > levels effects for each channel.

>> > So I though I can mimic that result just with a simple setup:

>> > 1. separate RGB  of the input,

>> > 2. add a color ramp to each channel (to get a remap of Hi and LOW value)

>> > 3. add a combine channel to recreate the final image

>> >

>> > The result looked promising but

>> > 1. to expose the value of the ramp you have to add a driver on each stop

>> > of

>> > the ramp

>> > 2. the driver (don't know why) in official 2.70 build seems cannot read

>> > the

>> > value of a node RGB.output or the input of the group even if it is

>> > readable

>> > in the python console (the driver simply show the path background in red

>> > color)

>> > 3. value are clamped in the 0-1 range so if values exceed this range

>> > they

>> > are remapped.. (well this is a known side effect driven by the node

>> > used...)

>> >

>> > I'm curious to know your approach :)

>> > Thanks,

>> > Francesco

>> >

>> >

>> > 2014-05-28 7:57 GMT+02:00 David McSween <3pointedit at gmail.com>:

>> >

>> >> I would certainly be interested in a 'colour matcher' node group.

>> >> Especially if it Rock My World as Mark says in the link ;-)

>> >>

>> >> These look really useful, it would be great if everyone could at least

>> >> match pedestal across their elements.

>> >>

>> >>

>> >> On Wed, May 28, 2014 at 2:07 PM, Sean Kennedy <mack_dadd2 at hotmail.com>

>> >> wrote:

>> >>>

>> >>> Hey guys,

>> >>>

>> >>> I made a few nodegroups we were discussing.

>> >>>

>> >>>

>> >>> https://www.dropbox.com/s/uj9kw6dm1sp3cot/clamp_nodes_screenshot_02.jpg

>> >>>

>> >>> I made a Value clamp, as Deigo had made. Then I made a RGB clamp,

>> >>> where

>> >>> you can set R, G, and B individually. And then I made the node I

>> >>> really

>> >>> wanted, a black levels node.

>> >>>

>> >>> When you're compositing one image over another, and they come from two

>> >>> different sources, they usually have completely different color values

>> >>> in

>> >>> the highs and lows (obviously, we all know this). At R&H, we had a

>> >>> great

>> >>> Black Levels node where we could simply sample a dark spot of a

>> >>> background

>> >>> plate, and the darks of the foreground plate would just shift to

>> >>> match. This

>> >>> works the same exact way. It was ideal for CG elements going over live

>> >>> action plates, because usually the general highs and overall color of

>> >>> the CG

>> >>> matched the plate fine, but the blacks always came in as absolute

>> >>> blacks, or

>> >>> sometimes negative blacks. This node made fixing it a 1-click

>> >>> operation.

>> >>>

>> >>> If anyone is interested, I can upload a blend file with the

>> >>> nodegroups.

>> >>> The clamps are super easy to make, though. But maybe the black levels

>> >>> one

>> >>> would be interesting to someone?

>> >>>

>> >>> Tomorrow I'm going make a node setup to easily replicate Mark

>> >>> Christiansen's techniques for matching the general colors of one plate

>> >>> to

>> >>> another. You can see the technique here in the free sample videos, if

>> >>> you're

>> >>> interested.

>> >>>

>> >>>

>> >>> http://www.lynda.com/After-Effects-tutorials/After-Effects-Compositing-Essentials-Matching-Foreground-Background/114913-2.html



>> >>>

>> >>> It's fun making these!

>> >>>

>> >>> Sean

>> >>>

>> >>> ________________________________

>> >>> From: f.paglia.80 at gmail.com

>> >>> Date: Sun, 25 May 2014 09:50:01 +0200

>> >>> To: bf-compositor at blender.org

>> >>> Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)

>> >>>

>> >>> Thanks for the advices Diego and David!

>> >>> Just a little thought:

>> >>> Adding lot of nodegroups in a single "category" - I mean in the same

>> >>> menu

>> >>> list - isn't that efficient... is there a way to manage their position

>> >>> in

>> >>> the SHIFT+A menu?

>> >>>

>> >>> Referenced node group are quite "risky" since compositing session

>> >>> works

>> >>> most likely WYSIWYG and as soon as you change something you have to

>> >>> check

>> >>> back each project... but I get your point Diego... I'm very used to

>> >>> linked

>> >>> group, they are so useful and I hope they will be empowered a lot with

>> >>> gooseberry since Proxyfication have room for for lot of improvement.

>> >>>

>> >>>

>> >>>

>> >>>

>> >>>

>> >>>

>> >>> 2014-05-25 4:26 GMT+02:00 David McSween <3pointedit at gmail.com>:

>> >>>

>> >>> Don't forget the addon Node Presets

>> >>>

>> >>> http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Compositing/Compositing_Presets



>> >>> I think you can add node groups and store them in a portable file.

>> >>>

>> >>> On 25 May 2014 09:59, "Diego Gangl" <dnicolas at gmail.com> wrote:

>> >>>

>> >>> >> It is possible to clamp (blacks and whites individually even), but

>> >>> >> whenever I want to do it I have to add gazillion nodes. It takes

>> >>> >> time.

>> >>> >> My

>> >>> >> intention is to make it with a single click.

>> >>>

>> >>> You can turn them into a group, plug the math values into group

>> >>> inputs, name it and bam! your own Clamp Node that you can add from the

>> >>> group menu.

>> >>>

>> >>> > Isn't there a way to develop few nodegroup store them somewhere and

>> >>> > recall

>> >>> > them in a personal group list or add them in the lists we already

>> >>> > have?

>> >>>

>> >>> There's two ways:

>> >>>

>> >>> 1- Make the groups in a new (empty) blend file, then save it as your

>> >>> start-up file (ctrl+U). The node groups will be available in every new

>> >>> file you make.

>> >>>

>> >>> 2- Make a "Node Library" file. Make all your groups there, then make a

>> >>> new empty file and link all the groups from the library file. Save it

>> >>> as your start-up file and you get all the groups. The cool thing is

>> >>> that if you tweak the groups inside the lib file, they will be upated

>> >>> in all the blend files that link them.

>> >>>

>> >>> Gooseberry is going to bring a lot of developement into asset

>> >>> management, so it will get better.

>> >>>

>> >>>

>> >>> 2014-05-24 7:00 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:

>> >>> > Isn't there a way to develop few nodegroup store them somewhere and

>> >>> > recall

>> >>> > them in a personal group list or add them in the lists we already

>> >>> > have?

>> >>> > Could it be a python add-on?

>> >>> > This would help us skip the tedious part of reloading those node

>> >>> > every

>> >>> > time

>> >>> > a new blend file is created and also could help us distribute those

>> >>> > nodes in

>> >>> > their coherent place.

>> >>> >

>> >>> >

>> >>> >

>> >>> > 2014-05-24 11:31 GMT+02:00 Bartek Skorupa (priv)

>> >>> > <bartekskorupa at bartekskorupa.com>:

>> >>> >

>> >>> >> It is possible to clamp (blacks and whites individually even), but

>> >>> >> whenever I want to do it I have to add gazillion nodes. It takes

>> >>> >> time.

>> >>> >> My

>> >>> >> intention is to make it with a single click.

>> >>> >> How much time did it take you to set up this fantastic node tree of

>> >>> >> yours?

>> >>> >> If it's more than one second - itś too much. It should be: Decision

>> >>> >> =>

>> >>> >> 1

>> >>> >> second later: DONE.

>> >>> >>

>> >>> >>

>> >>> >> Bartek Skorupa

>> >>> >>

>> >>> >> www.bartekskorupa.com

>> >>> >>

>> >>> >> On 24 maj 2014, at 00:10, Sean Kennedy <mack_dadd2 at hotmail.com>

>> >>> >> wrote:

>> >>> >>

>> >>> >> Ah, great idea! We could even set one up with RGB, one on each

>> >>> >> channel,

>> >>> >> and save it as a nodegroup.

>> >>> >> Thanks! So obvious, don't know why we didn't think of this. :)

>> >>> >>

>> >>> >> I'm going to set one up today.

>> >>> >>

>> >>> >> sean

>> >>> >>

>> >>> >> > From: dnicolas at gmail.com

>> >>> >> > Date: Fri, 23 May 2014 19:07:28 -0300

>> >>> >> > To: bf-compositor at blender.org

>> >>> >> > Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)

>> >>> >> >

>> >>> >> > Hi all, I don't know how Blender's handles colors internally but

>> >>> >> > wouldn't this work?

>> >>> >> > http://www.pasteall.org/pic/show.php?id=71736

>> >>> >> > (or are the V values already mapped to 0-1 from the separate

>> >>> >> > node?)

>> >>> >> >

>> >>> >> > Cheers,

>> >>> >> >

>> >>> >> > 2014-05-23 18:46 GMT-03:00 Sean Kennedy <mack_dadd2 at hotmail.com>:

>> >>> >> > > Could we set the value of the clamp? It could come in as

>> >>> >> > > defaults

>> >>> >> > > of

>> >>> >> > > 1.0 and

>> >>> >> > > 0.0, but we could alter it to whatever we wanted. At R&H, most

>> >>> >> > > of

>> >>> >> > > the

>> >>> >> > > time

>> >>> >> > > we clamped brights around 14-16. We'd only turn it down under

>> >>> >> > > that

>> >>> >> > > if

>> >>> >> > > we got

>> >>> >> > > bad pixels when rendering.

>> >>> >> > >

>> >>> >> > > If you had a superbright red, like R 12, G 3, B 4, and you put

>> >>> >> > > a

>> >>> >> > > clamp

>> >>> >> > > of 1

>> >>> >> > > on it, obviously it's going to set each value to 1, so what was

>> >>> >> > > red

>> >>> >> > > now

>> >>> >> > > reads as white. But it would still be useful.

>> >>> >> > >

>> >>> >> > > After Effects clamp tool

>> >>> >> >

>> >>> >> > >

>> >>> >> > > >

>> >>> >> > > > > >http://cdn.aescripts.com/media/catalog/product/cache/1/image/800x600/040ec09b1e35df139433887a97daa66f/f/t/ft-clamp-ui_1.png



>> >>> >> > >

>> >>> >> > > Nuke clamp is in the color grade node

>> >>> >> >

>> >>> >> > >

>> >>> >> > > >

>> >>> >> > > > > >http://docs.thefoundry.co.uk/nuke/63/pythondevguide/_images/getMinMax_01.png



>> >>> >> > >

>> >>> >> > > I'm not posting the images to say "this is how we should do

>> >>> >> > > it",

>> >>> >> > > but

>> >>> >> > > rather,

>> >>> >> > > to say it is useful and professional compositors would indeed

>> >>> >> > > use

>> >>> >> > > it

>> >>> >> > > often.

>> >>> >> > >

>> >>> >> > > In fact, I was working on a shot this week that could have used

>> >>> >> > > it. I

>> >>> >> > > was

>> >>> >> > > given stock footage from a client, and I have no idea how much

>> >>> >> > > they'll

>> >>> >> > > color

>> >>> >> > > correct it in post once I deliver the final vfx shot. SO I have

>> >>> >> > > to

>> >>> >> > > make sure

>> >>> >> > > all my blacks are in line with what is in the plate. I put a

>> >>> >> > > gamma

>> >>> >> > > on

>> >>> >> > > the

>> >>> >> > > plate just to view the black levels and see how they match up

>> >>> >> > > when

>> >>> >> > > pushed

>> >>> >> > > really far.

>> >>> >> > >https://dl.dropboxusercontent.com/u/10553822/clamp_blacks_01.jpg

>> >>> >> > >

>> >>> >> > > Since we don't have a clamp, I ended up putting a mix node

>> >>> >> > > right

>> >>> >> > > after

>> >>> >> > > the

>> >>> >> > > stock footage node, setting it to Lighten, and making the color

>> >>> >> > > over

>> >>> >> > > it

>> >>> >> > > black. then I slowly raised it while watching until the blacks

>> >>> >> > > all

>> >>> >> > > came in

>> >>> >> > > line. Would have been much easier to sample the value of the

>> >>> >> > > darkest

>> >>> >> > > dark I

>> >>> >> > > wanted in the shot, throw a clamp node on with the black clamp

>> >>> >> > > set

>> >>> >> > > to

>> >>> >> > > those

>> >>> >> > > values.

>> >>> >> > >

>> >>> >> > > In fact, at R&H, the Black Clamp node let you set an individual

>> >>> >> > > value

>> >>> >> > > for R,

>> >>> >> > > G, and B. And it had a color picker so you could just sample

>> >>> >> > > the

>> >>> >> > > image

>> >>> >> > > and

>> >>> >> > > the values would fill in automatically.

>> >>> >> > >

>> >>> >> > > Anyway, just throwing out my $0.02. Obviously I've found a

>> >>> >> > > workaround

>> >>> >> > > and

>> >>> >> > > can live with it, but it would sure be great to someday see a

>> >>> >> > > clamp

>> >>> >> > > node.

>> >>> >> > >

>> >>> >> > > ________________________________

>> >>> >> > > Date: Fri, 23 May 2014 14:21:40 -0700

>> >>> >> > >

>> >>> >> > > From: troy.sobotka at gmail.com

>> >>> >> > > To: bf-compositor at blender.org

>> >>> >> > > Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)

>> >>> >> > >

>> >>> >> > >

>> >>> >> > > On May 23, 2014 1:56 PM, "Bartek Skorupa (priv)"

>> >>> >> > > <bartekskorupa at bartekskorupa.com> wrote:

>> >>> >> > >

>> >>> >> > >> When I say: "clamp blacks" I always mean: set every value

>> >>> >> > >> below

>> >>> >> > >> 0.0

>> >>> >> > >> to

>> >>> >> > >> 0.0.

>> >>> >> > >> When I say: "clamp whites" I always mean: set every value

>> >>> >> > >> above

>> >>> >> > >> 1.0

>> >>> >> > >> to

>> >>> >> > >> 1.0.

>> >>> >> > >> Every compositing artist will know what I mean.

>> >>> >> > >

>> >>> >> > > If we can generate a clamp / scale node, I am all for it.

>> >>> >> > >

>> >>> >> > > I am saying there is no concept of white in a scene referred

>> >>> >> > > model,

>> >>> >> > > and as

>> >>> >> > > such, you have to be careful as to not write nodes that break

>> >>> >> > > the

>> >>> >> > > system.

>> >>> >> > >

>> >>> >> > > It is that simple. No white. No brighter than white. So sorry,

>> >>> >> > > "Every

>> >>> >> > > artist..." is actually "Every artist unfamiliar with HDR work."

>> >>> >> > >

>> >>> >> > > So a clamp node _must_ not make the erroneous assumption that

>> >>> >> > > 1.0

>> >>> >> > > means

>> >>> >> > > anything special, and rather provide for an arbitrary value

>> >>> >> > > range.

>> >>> >> > >

>> >>> >> > > If this all seems like speaking an alien language, it is

>> >>> >> > > precisely

>> >>> >> > > why

>> >>> >> > > I

>> >>> >> > > chimed in and said "Whoa."

>> >>> >> > >

>> >>> >> > > There are already nodes that are broken because of erroneous

>> >>> >> > > assumptions. It

>> >>> >> > > would be a shame to make more.

>> >>> >> > >

>> >>> >> > > With respect,

>> >>> >> > > TJS

>> >>> >> > >

>> >>> >> > >

>> >>> >> > > _______________________________________________ Bf-compositor

>> >>> >> > > mailing

>> >>> >> > > list

>> >>> >> > > Bf-compositor at blender.org

>> >>> >> > > http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >> > >

>> >>> >> > > _______________________________________________

>> >>> >> > > Bf-compositor mailing list

>> >>> >> > > Bf-compositor at blender.org

>> >>> >> > > http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >> > >

>> >>> >> > _______________________________________________

>> >>> >> > Bf-compositor mailing list

>> >>> >> > Bf-compositor at blender.org

>> >>> >> > http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >> _______________________________________________

>> >>> >> Bf-compositor mailing list

>> >>> >> Bf-compositor at blender.org

>> >>> >> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >>

>> >>> >>

>> >>> >>

>> >>> >> _______________________________________________

>> >>> >> Bf-compositor mailing list

>> >>> >> Bf-compositor at blender.org

>> >>> >> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >>

>> >>> >

>> >>> >

>> >>> >

>> >>> > --

>> >>> > Francesco Paglia

>> >>> > Vfx and Production Supervisor

>> >>> >

>> >>> > mobile  +39 347.82.12.473

>> >>> > e-mail   f.paglia.80 at gmail.com

>> >>> >

>> >>> >

>> >>> > _______________________________________________

>> >>> > Bf-compositor mailing list

>> >>> > Bf-compositor at blender.org

>> >>> > http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>> >

>> >>> _______________________________________________

>> >>> Bf-compositor mailing list

>> >>> Bf-compositor at blender.org

>> >>> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>>

>> >>>

>> >>> _______________________________________________

>> >>> Bf-compositor mailing list

>> >>> Bf-compositor at blender.org

>> >>> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>>

>> >>>

>> >>>

>> >>>

>> >>> --

>> >>> Francesco Paglia

>> >>> Vfx and Production Supervisor

>> >>>

>> >>> mobile  +39 347.82.12.473

>> >>> e-mail   f.paglia.80 at gmail.com

>> >>>

>> >>>

>> >>> _______________________________________________ Bf-compositor mailing

>> >>> list Bf-compositor at blender.org

>> >>> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>>

>> >>> _______________________________________________

>> >>> Bf-compositor mailing list

>> >>> Bf-compositor at blender.org

>> >>> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>>

>> >>

>> >>

>> >> _______________________________________________

>> >> Bf-compositor mailing list

>> >> Bf-compositor at blender.org

>> >> http://lists.blender.org/mailman/listinfo/bf-compositor

>> >>

>> >

>> >

>> >

>> > --

>> > Francesco Paglia

>> > Vfx and Production Supervisor

>> >

>> > mobile  +39 347.82.12.473

>> > e-mail   f.paglia.80 at gmail.com

>> >

>> >

>> > _______________________________________________

>> > Bf-compositor mailing list

>> > Bf-compositor at blender.org

>> > http://lists.blender.org/mailman/listinfo/bf-compositor

>> >

>> _______________________________________________

>> Bf-compositor mailing list

>> Bf-compositor at blender.org

>> http://lists.blender.org/mailman/listinfo/bf-compositor

>

>

>

>

> --

> Francesco Paglia

> Vfx and Production Supervisor

>

> mobile  +39 347.82.12.473

> e-mail   f.paglia.80 at gmail.com

>

>

> _______________________________________________

> Bf-compositor mailing list

> Bf-compositor at blender.org

> http://lists.blender.org/mailman/listinfo/bf-compositor

>

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-- 
Francesco PagliaVfx and Production Supervisor
mobile  +39 347.82.12.473e-mail   f.paglia.80 at gmail.com





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