Film-Tech Forum ARCHIVE: Dolby 3D, one eye darker

This is topic Dolby 3D, one eye darker in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=000906

Posted by Melanie Loggins (Member # 6454) on 09-26-2011, 12:37 PM:

I've looked all over the Dolby site and a fair bit here and I can't find anything, so I'm going to ask my stupid question: the guy who installed our equipment told us that, in 3D, there was no way to get both eyes equally bright. The left eye is darker than the right. We were told that if we increased the brightness in the left eye, the right eye would get darker. Not only does this make me hate watching 3D movies in my own theatre, it sounds a bit like bullshit. Anyone know?

Posted by Monte L Fullmer (Member # 2797) on 09-26-2011, 02:38 PM:

What happens when a 3D test pattern is thrown on the screen - does the same?

Best get the tech back and make him do things right, for others with Dolby 3D have no issues like this.

Posted by Marco Giustini (Member # 4544) on 09-26-2011, 04:01 PM:

Dolby 3D calibration procedure has a specific section to dial the brightness of the eyes and the software inside the server should compensate for any differences.
If the brightness is very different after the calibration I would keeo into consideration the following:

1. Check you are carefully following the server instructions (stop the playback when you are told to do so for example)
2. Check you are NOT using glasses to measure the colours. You MUST use appropriate filters
3. Make sure there is NO light in the auditorium when you shoot the colours
4. Make sure the colour wheel is installed as per Dolby specifications
5. Make sure the projector calibration is DISABLED when using Dolby 3D

A good Dolby 3D installation will have +/-0.5fL MAX difference between eyes. If you can see the difference with bare eyes, particularly on dark scenes, your Dolby 3D calibration is off.

You may have a defective wheel, but I'd start from the basics first.

Posted by Mark Gulbrandsen (Member # 72) on 09-26-2011, 04:15 PM:

It is BS for sure. The system is not calibrated properly. There could be a reason and that may be that you just don't have enough light to begin with and after calibration it would end up below the spec... I have seen this happen. What is the projector, lamp, screen and dimensions of screen? There is no real reason other then the installer didn't know what he was doing or what I mentioned above... or the light issue. It may be that your projector can take a larger lamp. On the other hand your brain should adjust to the difference in light levels pretty rapidly. Proper calibration is better...
Mark

Posted by Marco Giustini (Member # 4544) on 09-27-2011, 12:14 PM:

I've seen 3D shows with black levels VERY different between eyes and it was VERY annoying, particularly during dark scenes.