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

Wed May 28 13:15:36 CEST 2014

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
>>> >> > >
>>> >> > > _______________________________________________
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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
>>> >
>>> >
>>> > _______________________________________________
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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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>>
>>
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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
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