sounds like a bug. sounds like one is adjusting the mid point have you tried using a color lookup node after then read node to try and see ABOUT what the black mid and high difference is between the 2 choices?
Randy S. Little http://www.rslittle.com On Wed, Dec 21, 2011 at 01:35, Ron Ganbar <[email protected]> wrote: > Hi all, > you guys write faster than I read mail. > > There are two linear options in the gamma curve property of Nuke's Read node > when decoding R3D, one is called Linear, and the other is called Half Float > Linear. All the issues with 32bit float and 16bit half float and 16bit int > are clear and obvious. > What isn't clear is why when choosing Linear in the gamma curve we get a > washed image and choosing linear half float we get a good looking image. As > in choosing linear half float gives us a linear image (converted via the > Viewer to sRGB) and choosing linear actually gives us an sRGB image or > something. I just don't see why picking to encode the image as 32bit float > or 16bit half float will change the actual gamma curve of it. > Seems like a bug to me, or an unfortunate choice of terminology. > > > Ron Ganbar > email: [email protected] > tel: +44 (0)7968 007 309 [UK] > +972 (0)54 255 9765 [Israel] > url: http://ronganbar.wordpress.com/ > > > > On 21 December 2011 09:38, Randy Little <[email protected]> wrote: >> >> 18% grey isn't pushed to .18 .18=18% of 0-1 linear response. >> 18%grey is what happens if you mix 50%black and 50%white and spin it >> really fast. You get a scene average reflectance of 18%. The chips >> aren't reordering more then 16bits INT. the only reason you need/want >> float is when you start playing with Curves you start remaping the >> data and in this way you aren't going to lose anything. For Ron's >> issue my guess is that what he is getting is INT sRGB with the values >> remapped and in nuke you are getting linear without any remapping of >> values to fit under 1.0. THUS blacks aren't getting crushed in nuke >> like they are in redcine. ALL of these is pretty easy to solve with >> a macbeth cart or a greyscale wedge. >> >> Randy S. Little >> http://www.rslittle.com >> >> >> >> >> On Tue, Dec 20, 2011 at 23:20, Simon Björk <[email protected]> >> wrote: >> > The term half float linear is a bit of a strange name for a gamma curve >> > I >> > must say, and it definitely causes a lot of confusion. In this case, >> > from >> > what I understand, half float linear is a linear curve where 18% grey is >> > mapped to 0.18. This explains why bright values are pushed above >> > 1.0. However, I'm not full understanding what's happening. If that was >> > the >> > only thing that's happening compared to (the old and don't use) linear >> > option, I would think that you could match the two with a simple >> > multiply. >> > But you can't. Saturation/contrast is still way different between the >> > two. >> > >> > Regarding RedCineX, in newer versions (last year or so) it allows you to >> > export EXRs with values above 1.0. You don't have the half float linear >> > option in there, but actually it doesn't matter what gamma setting you >> > chose. If you render EXRs from RedCineX it will output linear EXRs with >> > 18% >> > grey pushed to 0.18. >> > >> > In my opinion the half float linear option in Nuke should be renamed to >> > something else. Or just replace the current linear option (which is >> > there >> > for legacy reasons). >> > >> > /Simon >> > >> > >> > 2011/12/20 Deke Kincaid <[email protected]> >> >> >> >> Either way the r3d reader set to linear will clamp at 1.0, set to half >> >> linear float will go beyond 1.0. I don't pretend to know what the red >> >> sdk >> >> is doing under the hood. Half linear float option does not exist under >> >> redcinex. >> >> >> >> -deke >> >> >> >> >> >> On Tue, Dec 20, 2011 at 13:45, Randy Little <[email protected]> >> >> wrote: >> >>> >> >>> clamped to 1.0 or raw data mapped to values between 0-1.0 with 3 >> >>> places of precision. But I am pretty sure the d/a in every camera is >> >>> integer and mapping data into integer space for its raw file. >> >>> http://www.rslittle.com >> >>> >> >>> >> >>> >> >>> >> >>> On Tue, Dec 20, 2011 at 13:37, Howard Jones <[email protected]> >> >>> wrote: >> >>> > 1.0 is half float/float even if not clamped ;) >> >>> > for Ron's question (if I read it right) >> >>> > >> >>> > Half float or 16 bit float is a less accurate version of 32 bit >> >>> > float. >> >>> > AFAIK The float being the floating point part of the number. you >> >>> > dont >> >>> > save >> >>> > 123.45678 you save 12345678 with a bit(?) for the position of the >> >>> > floating >> >>> > point. >> >>> > The difference between 16bit (half float) and 32 bit (float) is that >> >>> > with >> >>> > 16bit the length of that number gets truncated at a lesser degree of >> >>> > accuracy compared to 32bit. >> >>> > You could have 10 or 8bit float if you wanted, just not much point >> >>> > for >> >>> > what >> >>> > we do. Similarly you could have 32bit non-float if you really >> >>> > wanted, >> >>> > but >> >>> > again no point in our game afaic - as far as I care ;) >> >>> > >> >>> > Linear is linear, but again you could put any gamma or other curve >> >>> > in >> >>> > there >> >>> > if you wanted. >> >>> > >> >>> > http://en.wikipedia.org/wiki/Half-precision_floating-point_format >> >>> > >> >>> > Howard >> >>> > >> >>> > ________________________________ >> >>> > From: "[email protected]" <[email protected]> >> >>> > >> >>> > To: Nuke user discussion <[email protected]> >> >>> > Sent: Tuesday, 20 December 2011, 20:24 >> >>> > Subject: Re: [Nuke-users] Redcine-X VS Nuke >> >>> > >> >>> > 1.0 is half float if it encoded half float and clamp to 1.0 >> >>> > >> >>> > Sent from myTouch 4G >> >>> > >> >>> > ----- Reply message ----- >> >>> > From: "Deke Kincaid" <[email protected]> >> >>> > To: "Nuke user discussion" <[email protected]> >> >>> > Subject: [Nuke-users] Redcine-X VS Nuke >> >>> > Date: Tue, Dec 20, 2011 12:13 >> >>> > >> >>> > >> >>> > Last I knew RedcineX only outputs EXR to "linear" which caps out at >> >>> > 1.0, not >> >>> > half linear float. >> >>> > >> >>> > -deke >> >>> > >> >>> > On Tue, Dec 20, 2011 at 04:29, Simon Björk <[email protected]> >> >>> > wrote: >> >>> > >> >>> > I might be misunderstanding you, but why the srgb2lin conversion? >> >>> > RedcineX >> >>> > only outputs linear exrs so as far as I know you shouldn't use any >> >>> > colorspace convertions in Nuke if you chose that path. You can test >> >>> > this if >> >>> > you try different gamma curves in RedcineX and render to EXR. They >> >>> > should >> >>> > all look identical. >> >>> > >> >>> > Regarding my earlier post about half float linear gamma setting in >> >>> > Nuke >> >>> > should match a rendered exr from RedcineX, I just tested this and it >> >>> > doesn't >> >>> > seem to work. I'm pretty sure this worked earlier, but I might be >> >>> > wrong. The >> >>> > "linear gamma curve" in Nukes R3D importer is an old one and >> >>> > shouldn't >> >>> > be >> >>> > used. Not sure why it's still there. >> >>> > >> >>> > This whole R3D in other applications often causes problems. Same in >> >>> > After >> >>> > Effects. I find that the most reliable solution (still unreliable) >> >>> > is >> >>> > to >> >>> > output from RedcineX. >> >>> > >> >>> > /Simon >> >>> > >> >>> > >> >>> > >> >>> > 2011/12/20 Deke Kincaid <[email protected]> >> >>> > >> >>> > I forgot to mention that It all depends what file format your >> >>> > outputting. If >> >>> > your outputting to dpx or tiff then set the decode colorspace/gamma >> >>> > curve >> >>> > the same as RedcineX but in the write node set the colorspace to >> >>> > "linear". >> >>> > While working with the R3d though, the viewer will look different >> >>> > from >> >>> > RedcineX unless you set it to linear. After reading back in the >> >>> > dpx/tiff, >> >>> > then you can set the viewer back to srgb and it will look correct. >> >>> > >> >>> > If your outputting to Exr from RedcineX then you need add a >> >>> > colorspace >> >>> > node >> >>> > with in:sRGB and out:Linear (Read node settings all should match >> >>> > RedcineX). >> >>> > While this is technically incorrect but it will give you the >> >>> > equivalent of >> >>> > burning the grade into the EXR. >> >>> > >> >>> > People here are mentioning using Half Linear Float which does >> >>> > properly >> >>> > linearize the curve form the chip when going to EXR. You would need >> >>> > to >> >>> > extract a lut between the linear R3d and your director's color to >> >>> > use >> >>> > as a >> >>> > viewer lut and use that in the write node. >> >>> > >> >>> > -deke >> >>> > >> >>> > >> >>> > On Tue, Dec 20, 2011 at 00:15, Ron Ganbar <[email protected]> wrote: >> >>> > >> >>> > Thanks for this Deke. >> >>> > The settings are all the same, but looking at the Nuke Viewer set to >> >>> > sRGB, I >> >>> > see a very washed out image - what I would normally consider a >> >>> > Cineon >> >>> > looking image. Looking at the Redcine-X viewer it looks correct. >> >>> > Any ideas? >> >>> > >> >>> > >> >>> > Ron Ganbar >> >>> > email: [email protected] >> >>> > tel: +44 (0)7968 007 309 [UK] >> >>> > +972 (0)54 255 9765 [Israel] >> >>> > url: http://ronganbar.wordpress.com/ >> >>> > >> >>> > >> >>> > >> >>> > On 20 December 2011 09:48, Deke Kincaid <[email protected]> >> >>> > wrote: >> >>> > >> >>> > First, try hitting the "Metadata" button in the read node. That >> >>> > should >> >>> > make >> >>> > it grab the right color settings. If not you can match the same >> >>> > settings in >> >>> > Nuke as the one he has in RedcineX (they should all be named the >> >>> > same). >> >>> > >> >>> > Also make sure your using Nuke 6.3v5 because it includes RedGamma2 >> >>> > and >> >>> > RedColor2 which is missing from versions before that (older SDK). >> >>> > >> >>> > -deke >> >>> > >> >>> > On Mon, Dec 19, 2011 at 23:34, Ron Ganbar <[email protected]> wrote: >> >>> > >> >>> > Hi all, >> >>> > I don't have a lot of experience with converting R3D files, but I so >> >>> > far did >> >>> > it with Nuke and was pretty happy with the result. >> >>> > However, a director, who is technically minded, just told me that >> >>> > when >> >>> > he >> >>> > takes something into Redcine-X and without changing the color at all >> >>> > he >> >>> > gets >> >>> > something he likes. I did the same thing, and indeed the image looks >> >>> > nice. >> >>> > When I do the same thing in Nuke I get a very washed image. What's >> >>> > the >> >>> > output colorspace of the Nuke R3D read node? How can I get the same >> >>> > kind of >> >>> > output from Nuke's Read node to Redcine-X's output? >> >>> > >> >>> > Thanks, >> >>> > Ron Ganbar >> >>> > email: [email protected] >> >>> > tel: +44 (0)7968 007 309 [UK] >> >>> > +972 (0)54 255 9765 [Israel] >> >>> > url: http://ronganbar.wordpress.com/ >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > >> >>> > >> >>> > -- >> >>> > -------------------------------- >> >>> > Stiller Studios >> >>> > Lidingö/Sweden >> >>> > >> >>> > Simon Björk >> >>> > Stiller Studios >> >>> > +46 (0)8 555 23 560 >> >>> > Ekholmsnäsvägen 40, S-181 41 Lidingö >> >>> > [email protected] >> >>> > www.stillerstudios.se >> >>> > >> >>> > find us: >> >>> > >> >>> > >> >>> > http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all >> >>> > >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> > >> >>> > >> >>> > _______________________________________________ >> >>> > Nuke-users mailing list >> >>> > [email protected], http://forums.thefoundry.co.uk/ >> >>> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >>> _______________________________________________ >> >>> Nuke-users mailing list >> >>> [email protected], http://forums.thefoundry.co.uk/ >> >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >> >> >> >> >> >> >> _______________________________________________ >> >> Nuke-users mailing list >> >> [email protected], http://forums.thefoundry.co.uk/ >> >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > >> > -- >> > -------------------------------- >> > Stiller Studios >> > Lidingö/Sweden >> > >> > Simon Björk >> > Stiller Studios >> > +46 (0)8 555 23 560 >> > Ekholmsnäsvägen 40, S-181 41 Lidingö >> > [email protected] >> > www.stillerstudios.se >> > >> > find us: >> > >> > http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> _______________________________________________ >> Nuke-users mailing list >> [email protected], http://forums.thefoundry.co.uk/ >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > > > > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users _______________________________________________ Nuke-users mailing list [email protected], http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
