Some tips...

[Steve Sherrick]

I ended up going the CRT route after all. Couldn't afford the high end LCDs, so it seemed to make sense to get a precisely calibrated CRT.

Steve

 

[GlennChan]

The meaured gamma of a Sony BVM is in the 2.4 to 2.5 range. This is the industry standard.

1- Hmm I've seen some figures measuring Sony CRTs to be 2.35. Though there is a really wide range of figures.

Thor Olson's "Behind gamma's disguise" goes into that. It's likely better if you don't simplify things down into a single number, since the measured response of a CRT doesn't follow a nice power curve.

2- IMO the more important issue is that Rec. 601 and Rec. 709 don't really specify what the transfer function of a monitor should be. (Where transfer function is a fancy way of saying how the input values map to light coming out of the monitor.) This has been ok since broadcast-grade CRTs have transfer functions similar to each other (determined by the physics of a CRT AFAIK) / the Sony BVM is considered the gold standard.

Now that companies are coming out with LCD monitors, I believe there is some confusion as to what a LCD's transfer function should be. There is a eCinemasys powerpoint around where they think 2.2 is the standard (and is what their LCD does) whereas they measure a Sony BVM to have a gamma of about 2.35. It may not be a good thing that their interpretation differs.

Ideally some standards body should set a standard as to what transfer function an ideal LCD should have. And some system for dealing with varying black levels.

The BMV Ds also use SMPTE C phosphor, which means all HD content is SMPTE C vs. 709 color gamut.

Technically Rec. 709 calls for Rec. 709 colors / primaries, not SMPTE C. The Sony LCDs can switch to show different primaries I think... e.g. it's like they had SMPTE C phosphors when showing SD (NTSC countries except Japan), EBU phosphors when showing SD (PAL countries), and Rec. 709 phosphors when showing HD.

3- CRTs have some limitations to them. They don't do full 1920x1080 resolution well. They flare... bright scenes will raise black level and decrease color saturation. They tend to drift in calibration. The phosphors wear out. They are also prone to light reflecting off the face of the monitor... if you have ambient lighting, a LCD can have better black levels than a CRT.

Also, most consumers are viewing HD on LCDs more than CRT, it makes sense to monitor for what most people see and (to some degree) the lowest common denominator.

On the other hand, LCDs have their share of problems (e.g. any panel that isn't 1920x1080/1200 of course won't do full HD resolution). They have gotten a lot better recently though.

Then again it's a bit of a moot point as it will be hard to get good CRTs and most viewers are moving to LCD. Though for SD there may still be a lot of people watching on interlaced TV sets... SD broadcast monitors like Sony PVMs are still good.

 

[Steve Sherrick]

Glenn I have followed your posts here and elsewhere on this issue and it seems like the only way to really do this right is to have multiple reference monitors. I suppose not a big deal for larger suites that have the budget, but it does make it an intriguing problem for smaller suites that are working in HD and SD and don't have the funds to have multiple reference monitors. For me, it will be Black Magic HDSDI>HD Link > LCD for HD and Sony PVM 14M4U for SD and checking HD downconversion. This should give me some idea of what I'm doing when color correcting, but I'm sure it's not the ideal setup.

Steve

 

[Michele Gavazzeni]

According to FCP2 user manual

FCP & QT Movies

Final Cut Pro assumes that QuickTime movies for codecs that support the YUV color spaceare are created with a gamma of 2.2.

When you output the sequence to video, or render it as a QuickTime movie, the gamma of the output is identical to that of the original.

However, during playback on your computer's monitor, Final Cut Pro automatically lowers the gamma of a sequence playing in the Canvas to 1.8 for display purposes.

This is to approximate the way it will look when displayed on a broadcast monitor.
This onscreen compensation does not change the actual gamma of the clips in your sequence.

FCP & RGB files

Final Cut Pro assumes that all RGB image files are created with a gamma of 1.8.
When RGB image files are imported into Final Cut Pro and edited into a sequence set to 8- or 10-bit YUV rendering, the gamma is automatically boosted to 2.2 in an attempt to match the other video files in your project.

During playback on your computer's monitor, Final Cut Pro lowers the gamma of the sequence playing in the Canvas to 1.8 for display purposes, but the still image clips in your sequence are still boosted when the sequence is output to video or rendered as a QuickTime movie.

 

[David Battistella]

Check your CF card reader for compatibility with REDCODE files BEFORE you shoot something important.

Jim

Is there a list of RED recomended card readers?

What brand was the one giving one user some trouble?

David

 

[Stacey Spears]

Technically Rec. 709 calls for Rec. 709 colors / primaries, not SMPTE C.

Technically yes, practically, no. Shops like MPI, Sony (CTHV), Universal, EFilm, Fotokem, etc... all use the BVM for HD. Most HD content today has been color corrected against SMPTE C primaires. I would also argue that none of these shops are using LCDs to color grade. Sony has a pro LCD, but it is not ready yet per Don Eklund, at Sony. (CTHV)

At least one consumer DLP allows you to switch between SMPTE C, 709 and EBU primaries. I know EFilm also uses a lot of DCinema (Christie 2ks) displays and Nicholas would program a lot of custom LUTs depending on the application.

The eCinemasys mentions ~2.39 - 2.45 for the gamma of the BVM. http://www.ecinemasys.com/technotes/files/AN009 - Display Technology.pdf

Standard calibration for a BVM is 25fl and D65. While they can easily hit D65, they can't produce 25fl w/o clipping. They tend to clip around 20fl. Perhaps I should say bloom instead of clip since it is a CRT.

At any rate, if you don't have a BMV to color grade on, you want to find a display that emulates it.

Final Cut Pro assumes that all RGB image files are created with a gamma of 1.8. When RGB image files are imported into Final Cut Pro and edited into a sequence set to 8- or 10-bit YUV rendering, the gamma is automatically boosted to 2.2 in an attempt to match the other video files in your project.

That is a bad assumption on their part. Is there a mode/option in FCP that does not make any adjustments to gamma? Or a file format I can bring into and out of that is safe?

 

[GlennChan]

The eCinemasys mentions ~2.39 - 2.45 for the gamma of the BVM. http://www.ecinemasys.com/technotes/...Technology.pdf

Ah, my mistake. I might also have mis-read their interpretation of gamma.

 

[Michele Gavazzeni]

Is there a mode/option in FCP that does not make any adjustments to gamma?

No...

Or a file format I can bring into and out of that is safe?

.mov
also when you export a composition from shake to be used in FCP is a better idea to export as .mov instead of using an image sequence.