Originally Posted by James Freeman
Here is how my APL slides look like:
Since I don't have a plasma to test, I've generally been curious if large areas of white in a test pattern might tend to skew xy measurements. Larger measurement areas generally make an image more practical for small displays and projectors. On the other hand white is rather uncommon for many images, so without testing it may make sense to limit the amount of bright areas in a pattern, similar to the example above. In spite of all the discussion around which patterns to use on plasma, there isn't a lot of data to look at in my opinion, but Chad B's measurements
on his own APL pattern
seem to indicate some clear xy variation against other measurement patterns, so I have to wonder if the bright areas might be a part of the usual complaints about prior fixed-luminance measurement patterns.
The Chad B APL pattern
has an APL around 19%, but it has larger measurement areas like white, so the average luminance is around 13% for a 2.2 gamma. The example above seems to have an APL around maybe 26%, and an average luminance about 8% at 2.2 gamma. The example above seems a reasonable average in comparison to the numbers that Zoyd posted
, and I doubt if the lower average luminance would hurt in comparisons against typical patterns. Gamma measurements should be generally similar to the trends from other fixed-luminance patterns, but I'm not sure how RGB would turn out or what people might subjectively decide about measurements on various plasma displays. Personally I tend to agree that when using a display type that is known to vary depending on the image displayed it makes sense to have some other reference, like another display that does not vary depending on the displayed image, but as far as I can tell such considerations are not the general forum opinion.
BTW. It would be very nice if someone could teach me how to generate a standard 16-235 MP4 video like the ones on the AVS709 disk from my PNG images.
The process used for this project is generally covered in:
AVS HD 709 - Blu-ray & MP4 Calibration