Larry Baum Posted September 11, 2022 Share Posted September 11, 2022 On the face of it the question may seem absurd, since with film having a larger gamut than sRGB/REC709 and with stills film scanners all handling wide gamut color scans for ages, I'd think a mega expensive pro motion picture film scanner would certainly be able to output in wide gamut color but so far, as best as I can tell, each little sample I have received seems to be locked into sRGB/REC709 primary locations. It doesn't seem to matter whether Print or PrintLog option was used or whether it is DPX16, DPX10, DNG or ProRes4444. If I look at the DNG output in an exif viewer and look at the Forward Matrix it seems be one incredibly close to sRGB/REC709 primary locations (perhaps just slightly twisted since it seems to be in reference to D50 values instead of D65). If I force programs to assign color primary locations of sRGB/REC709, all files seem to look about the same as just letting programs load them as default. Also I see that the DNG file has the ColorimetricReference tag set to display referred (like a JPG) rather than scene referred (like most true RAW files would). If I have a display set to REC709 and assign the file to be interpreted as if it is REC709 it looks pretty normal and not all washed out and slightly twisted in color if it was stored in reference to wide gamut color primary locations. Like if you take a ProPhotoRGB image and do that it looks horribly dull. And if switch the display to native wide gamut and view one of the samples assigned to be interpreted as REC709 it look radioactive instead of at least somewhat normal. If I try to load a DPX16 frame into Photoshop it says no color profile found for file, if I assign it to be sRGB it looks pretty normal and about how it looks loaded into Resolve or PremierePro. Now sure the files are stored in more than 8bits per channel and some samples were log like DPX10LOG and so the gradations are finer than 8bit SDR REC709 and the tonal curve may be way different for like the DPX10LOG files and such, but the color primary locations just seem awfully like they are sRGB/REC709. One odd side note is that Adobe ACR loads the DNG output looking about 1500K color temp different than Resolve does (interestingly the AsShotXY is D50 as is the shot light source and sRGB/REC709 are based on D65, so 1500K apart so it seems some programs are maybe accounting for that and some not, with the files being listed as display referred, maybe Adobe is technically correct in that it treats them only as pseudo-RAW and doesn't adjust any color temp stuff at all and just loads everything exactly as is once the ForwardMatrix and AnalogBalance matrices are applied, although I suspect the 1500K different look of the ProRes samples and how they load into Resolve or the DPX16 loads into PremierePro or the DPX10Log loads into PremierePro with the LUT applied). So for all these reasons I feel like the scanner seems to be most likely only giving sRGB/REC709 standard gamut locked color primary referenced output and clipping what the film is capable of (in some frames you even see the gamut plot just straight line up against the edge of sRGB/REC709 gamut which means the original film surely extended past that gamut). Does anyone have any idea what could be going on? Is there some special setting that the scanner is missing setting in order to get native gamut output from the scanner? Again I am not talking about bit depth or fineness of gradations or LOG vs this or that or anything to do with tonal curve I am talking about color palette, where the locations of the three primaries are set. Now maybe the film is way more saturated than I think and it really is somewhat wide gamut, maybe a little shy of P3 or something but still looks kinda normal treated as sRGB/REC709 color primaries, but then how come the ForwardMatrix in the DNG basically appears to reference sRGB gamut? And if it is some custom semi-wide gamut, then how come some of the files have no reference as to where the primaries should be? How could anything know what the DPX16 data or what not is supposed to be in reference to? Maybe they just default to guessing REC709 if nothing else is there to go by but then how does the user know what to do with the files? And how come the cubeLUT the scanner spit out for the DPX10LOG seems to give the same color look as REC709 primaries? Thanks. Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.