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<body class='hmmessage'><div dir='ltr'>Ah, great idea! We could even set one up with RGB, one on each channel, and save it as a nodegroup.<div>Thanks! So obvious, don't know why we didn't think of this. :)</div><div><br></div><div>I'm going to set one up today.</div><div><br></div><div>sean<br><br><div>> From: dnicolas@gmail.com<br>> Date: Fri, 23 May 2014 19:07:28 -0300<br>> To: bf-compositor@blender.org<br>> Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)<br>> <br>> Hi all, I don't know how Blender's handles colors internally but<br>> wouldn't this work?<br>> http://www.pasteall.org/pic/show.php?id=71736<br>> (or are the V values already mapped to 0-1 from the separate node?)<br>> <br>> Cheers,<br>> <br>> 2014-05-23 18:46 GMT-03:00 Sean Kennedy <mack_dadd2@hotmail.com>:<br>> > Could we set the value of the clamp? It could come in as defaults of 1.0 and<br>> > 0.0, but we could alter it to whatever we wanted. At R&H, most of the time<br>> > we clamped brights around 14-16. We'd only turn it down under that if we got<br>> > bad pixels when rendering.<br>> ><br>> > If you had a superbright red, like R 12, G 3, B 4, and you put a clamp of 1<br>> > on it, obviously it's going to set each value to 1, so what was red now<br>> > reads as white. But it would still be useful.<br>> ><br>> > After Effects clamp tool<br>> > http://cdn.aescripts.com/media/catalog/product/cache/1/image/800x600/040ec09b1e35df139433887a97daa66f/f/t/ft-clamp-ui_1.png<br>> ><br>> > Nuke clamp is in the color grade node<br>> > http://docs.thefoundry.co.uk/nuke/63/pythondevguide/_images/getMinMax_01.png<br>> ><br>> > I'm not posting the images to say "this is how we should do it", but rather,<br>> > to say it is useful and professional compositors would indeed use it often.<br>> ><br>> > In fact, I was working on a shot this week that could have used it. I was<br>> > given stock footage from a client, and I have no idea how much they'll color<br>> > correct it in post once I deliver the final vfx shot. SO I have to make sure<br>> > all my blacks are in line with what is in the plate. I put a gamma on the<br>> > plate just to view the black levels and see how they match up when pushed<br>> > really far.<br>> > https://dl.dropboxusercontent.com/u/10553822/clamp_blacks_01.jpg<br>> ><br>> > Since we don't have a clamp, I ended up putting a mix node right after the<br>> > stock footage node, setting it to Lighten, and making the color over it<br>> > black. then I slowly raised it while watching until the blacks all came in<br>> > line. Would have been much easier to sample the value of the darkest dark I<br>> > wanted in the shot, throw a clamp node on with the black clamp set to those<br>> > values.<br>> ><br>> > In fact, at R&H, the Black Clamp node let you set an individual value for R,<br>> > G, and B. And it had a color picker so you could just sample the image and<br>> > the values would fill in automatically.<br>> ><br>> > Anyway, just throwing out my $0.02. Obviously I've found a workaround and<br>> > can live with it, but it would sure be great to someday see a clamp node.<br>> ><br>> > ________________________________<br>> > Date: Fri, 23 May 2014 14:21:40 -0700<br>> ><br>> > From: troy.sobotka@gmail.com<br>> > To: bf-compositor@blender.org<br>> > Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)<br>> ><br>> ><br>> > On May 23, 2014 1:56 PM, "Bartek Skorupa (priv)"<br>> > <bartekskorupa@bartekskorupa.com> wrote:<br>> ><br>> >> When I say: "clamp blacks" I always mean: set every value below 0.0 to<br>> >> 0.0.<br>> >> When I say: "clamp whites" I always mean: set every value above 1.0 to<br>> >> 1.0.<br>> >> Every compositing artist will know what I mean.<br>> ><br>> > If we can generate a clamp / scale node, I am all for it.<br>> ><br>> > I am saying there is no concept of white in a scene referred model, and as<br>> > such, you have to be careful as to not write nodes that break the system.<br>> ><br>> > It is that simple. No white. No brighter than white. So sorry, “Every<br>> > artist...” is actually “Every artist unfamiliar with HDR work.”<br>> ><br>> > So a clamp node _must_ not make the erroneous assumption that 1.0 means<br>> > anything special, and rather provide for an arbitrary value range.<br>> ><br>> > If this all seems like speaking an alien language, it is precisely why I<br>> > chimed in and said “Whoa.”<br>> ><br>> > There are already nodes that are broken because of erroneous assumptions. It<br>> > would be a shame to make more.<br>> ><br>> > With respect,<br>> > TJS<br>> ><br>> ><br>> > _______________________________________________ Bf-compositor mailing list<br>> > Bf-compositor@blender.org<br>> > http://lists.blender.org/mailman/listinfo/bf-compositor<br>> ><br>> > _______________________________________________<br>> > Bf-compositor mailing list<br>> > Bf-compositor@blender.org<br>> > http://lists.blender.org/mailman/listinfo/bf-compositor<br>> ><br>> _______________________________________________<br>> Bf-compositor mailing list<br>> Bf-compositor@blender.org<br>> http://lists.blender.org/mailman/listinfo/bf-compositor<br></div></div> </div></body>
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