Technical Articles and Editorials
- Written by Chris Heinonen
- Published on 08 May 2013
For The Expert
If you are familiar with these controls on your display, or you already have the first Spears & Munsil disc, there are still many more features included on this disc that are very useful. First on that list for me are the new Equal Energy windows for doing measurements for calibration. Typical measurements for calibration are done using windows or fields of the specific color you are looking to measure. For most display types, this works fine, but for plasmas in particular, they are not ideals.
All plasma displays have an automatic brightness limiter (ABL from here on) that regulates the amount of light output from the screen. With small windows, even a 100% white pattern may not cause it to kick in, but with full fields, it will certainly kick in. Because all displays work differently, and the ABL is different on all of them, you can calibrate using windows but get a different result because of how the ABL works.
One solution to this is to use equal energy patterns, where the light output is the same no matter which pattern is up. Most films have an average picture level of around 30-40% for brightness, so a 100% white field almost never comes into play. Using patterns that more closely mimic that level of output can help to more accurately reflect how the ABL works, and give you better real-world performance, even if test charts look identical to windows. Spears & Munsil has a new set of equal energy patterns that can be used for this, and have been designed to be more accurate than any others out there. Not everyone finds that equal energy patterns produce a better result, but for those with a plasma, it is a good approach to try and see how they work compared to windows.
Another important setting to check is the video-processing mode on your Blu-ray player and display. On Blu-ray movies, we now get the film in 24p format instead of 60i, so 3:2 pull-down isn't as essential as it once was. However, we still get a lot of 60i content for concerts and some TV shows, and movies on TV are 60i so 3:2 pull-down on your display need to work correctly to get the full resolution there. Using the 2:2 and 3:2 test patterns, you can determine if your devices should remain in the Auto mode that most ship in, or if you should choose one of the other modes that they offer to get better performance. In testing these devices, we've often found the default mode to be incorrect, but most people that buy them never know this, and endure worse performance because of it.