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

Diego Gangl dnicolas at gmail.com
Wed May 28 19:27:40 CEST 2014 

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
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>> >>> >> > >
>> >>> >> > _______________________________________________
>> >>> >> > Bf-compositor mailing list
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>> >>> >> _______________________________________________
>> >>> >> Bf-compositor mailing list
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>> >>> >> http://lists.blender.org/mailman/listinfo/bf-compositor
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>> >>> >>
>> >>> >>
>> >>> >> _______________________________________________
>> >>> >> Bf-compositor mailing list
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>> >>> >> 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
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>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> 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
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>> >>
>> >>
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>> >
>> >
>> >
>> > --
>> > 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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>> Bf-compositor at blender.org
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>
>
>
>
> --
> Francesco Paglia
> Vfx and Production Supervisor
>
> mobile  +39 347.82.12.473
> e-mail   f.paglia.80 at gmail.com
>
>
> _______________________________________________
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