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I got a new lamp for my Mits DLP. I have the updated 64 bit ArgyllCMS and DisplayCAL (as of 10/28/2016). Did all my usual pre cal/profiling stuff. Set light output level (target is ~35ft-L but set a tad higher for headroom for 3DLUT and drifting with age), white to 65k, black clipping, did all the 100% on RGBYCM using the manual controls. Pretty much all the defaults when running DisplayCAL, 1886 gamma, 1553 patches. I ran a profile/calibration and tested it, all the numbers looked good (sorry no report but the highest error is 2.5 in the Purple color checker with HCFR). I get this weird purple, yellow, and green hues in shades of stuff usually noticible with people’s faces. It seems like there’s a lot of color clipping IMO, hard to verify but there should be more shades but now there’s less? It’s hard to explain. Anyway here’s some pics of at least the purple problem:
Shot of the TV, crappy pic but you can see the purple in oval to the right of his face:
Direct screenshot from the same scene from the source:
I kinda think there’s a problem with the greyscale. I ran a 20pt measurement for greyscale and everything was low DE, maybe 1.4 tops. Should I edit the test chart for more neutral patches (I’m guessing that’s mostly greyscale stuff)? I’m not quite sure what to do. I swapped lamps since I didn’t notice it before. It’s still there but the old lamps are much dimmer and it doesn’t show up that bad with the old lamps and with the eeColor off so that wasn’t influencing it. The ring looks a lot more like it should (but dimmer) with the old lamp than the new lamp but I don’t get how that quite works.
Anyone have any ideas? This is driving me nuts.
I ran another calibration. It now destroys my picture. It measures fine but the picture, ugh there’s blocky artifacts everywhere, no more subtle tones, it almost looks 8-bit ish, it’s hard to explain. 🙁
Attach the profile and related files please (next to “Settings”, with profile selected, click “Create compressed archive…”).
Ok, here’s the last one I generated. In previous versions I always used the madVR preset to utilize madtpg and selected eeColor .txt file output. Did that change? At this point that’s about all I can think of.
The TV seems to be quite bright (142 cd/m2) but contrast is low (only 624:1). I would recommend against using BT.1886 on such a low-contrast display, because it will exaggerate near-black detail, and with lesser quality video material, this can make compression artifacts visible. The 3D LUT tone curve choice also depends on your ambient lighting. If the environment is dim, try 3D LUT tone curve “Custom”, gamma 2.3 “Relative” and raise black output offset to around 95%. You can generate 3D LUTs with different tone curve settings from the existing profile without the need to run additional measurements.
Thanks! It’s really odd cuz I’ve used the BT1886 tone curve for the last 2 years and it always worked well with this display. I replace the lamp and BAM this happens. I usually set it slightly bright since it’ll dim with age. I noticed the contrast ratio being that low and thought it was really odd. It used to be around 1000:1 IIRC. The environment is dim, I usually only use an Ideal-Lume Bias light. I’ll try lowering the brightness closer to 120 cd/m2 and try the custom tone curve you recommend.
If you want to have a similar curve as BT.1886 would give on a 1000:1 contrast display you can also try 2.2 “relative” with 60% output offset.
I think there’s something wrong with this TV or the lamp. Probably time to ditch the DLP ugh. No matter what I do with the 3DLUT it really destroys picture quality now. It used to be perfect and now it’s not. I have some old lamps I can throw in it and see but they aren’t very bright anymore. :/ I checked an old calibration report and the contrast ratio was ~850:1 and now I can’t get it much above 650:1 and it doesn’t matter if I change the lamp from Standard or Bright (Bright used to be perfect). I haven’t fully burned in the lamp yet though, only about 80 hours.
