![]() When using bt1886 calibrated grading monitor the colorist will pull the shadows down when grading till it looks good to him, this content will look as it should ONLY on a bt1886 calibrated screen. Watching content that was graded on a BT1886 calibrated studio monitor on a black compensated gamma display (most of them) will crush the black even more. With infinite black level BT1886 will result in exactly Gamma 2.4 power curve. #Displaycal lcd type professionalProfessional OLED grading monitors like the Sony PVM/BVM series have minimum output level setting that usually set to 0.05 or 0.1 nit resulting in a contrast ratio of 1000:1 or 2000:1. I don't think bt1886 arguments have much to do with viewing condition, it is the fact that it is trying to compensate for different black level and lifting the shadow like mad.(when rest of the world aren't doing the"standard".) After all, what's the point of using proper color management frameworks when we're having so much fun arguing to death about the shape and parameters of a gamma curve? I think that's asking for ponies and unicorns at this point, though. That would quickly put an end to the pointless debates and speculation. To be fair, color experts would probably raise eyebrows at this debate and would recommend that the video industry ditch this whole gamma business and switch to more modern and robust viewing condition management workflows, such as CIECAM02, along with standards that actually define viewing conditions in the first place (there is no mention of viewing conditions in BT.1886). This is why the ArgyllCMS docs () recommend an effective gamma of 2.4 for dark conditions (higher than BT.1886, at least for non-perfect displays), and 2.2 for dim conditions. #Displaycal lcd type movieIf you take a movie that was graded in a dim room (which AFAIK is the norm), and watch it in a pitch-black room, you need to increase gamma to compensate. You're not taking viewing conditions into account, which are extremely important when determining the correct viewing gamma. That's kind of the point of having a standard. ![]() They're supposed to be calibrated to BT.1886. Are you claiming that they're wrong, and if so, do you have specific evidence to back up your case? So what? Obviously the people who wrote BT.1886 standardized on that shape on purpose, otherwise they would just have mandated a pure power curve. This is completely normal and is working as intended - the whole point of BT.1886 is to compensate for such displays by lowering effective gamma. However, because a BT.1886 curve (in general) is not a pure power curve, the effective gamma ("average" gamma, or best fit for a pure power curve) is closer to 2.2 when a display with a non-perfect black point is used. ![]() Standard BT.1886 has a technical gamma of 2.4, in other words, 2.4 is used as the exponent. I personally use 70% output offset (30% input offset) Gamma 2.2 when I calibrate with Displa圜AL and ArgyllCMS because it resembles to my native monitor gamma curve and because it does not compress the blacks as much as 100 output offset.ĭon't confuse these, HCFR uses input offset whether Displa圜AL uses output offset, same thing different name and proportional to one another. I don't think anyone can tell what input/output offset % the studios use but it's definitely not 100% input. If you watch this content on a BT1886 calibrated display you WILL have wrong shadows and more importantly wrong colors. If the grading monitor is an OLED, the minimum black level will be set to 0.1 or 0.05 to have contrast ration of 1000:1 or 2000:1 according to ITU specification of Grade A monitor. SDR movies are graded on a typical 1000:1 LCD studio monitor calibrated to black compensated gamma 2.2. It also doesn't follow 2.2 or 2.4 above or below 50% input. If you set Override Black to 0 nit, the gamma will be 2.4 spot on across whole luminance range.Ġ input offset for maximum black compression, 100 for less compression but less true gamma curve below 50% input.Ĭlearly BT1886 is nowhere near 2.4 with a 1000:1 display. ![]() Set to gamma to 0 and input offset to 100%, to use the BT1886 equation. You can play with it and just click Apply to see the new curve. Peak luminance is always 100 nit, so set Override Black to 0.1 nit to have a 1000:1 typical contrast ratio display (100/0.1 = 1000). HCFR also lets you change the Black output/input offset or the shadow compression level. #Displaycal lcd type softwareThis software will let you plot EOTF curves and change their parameters like minimum light level which will plot the curve differently according to this. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |