Although this topic was discussed here and elsewhere, it turned out to be impossible to get an accurate information how modern plasma displays actually display color. What we have on the internet are some rare descriptions and several patents, mostly from 10 years ago, and some marketing stuff, claiming 600 Hz subfield drive and billions of colors displayable by PDP. Classical description is that each frame consists of 8 subfields, so we have 256 levels of each color. Somewhere we can read about more subfields and more levels, somewhere we can read that not all levels are used because of false contouring effect etc ... dithering is frequently mentioned, but not how much dithering we actually have ... etc.
So, in the absence of accurate information, I decided to make a timewarp of one PDP to find out. I want to point out that I made it just out of curiosity, because I'm a kind of technical guy, and not to start a war LCD against PDP. I'm quite satisfied with the TV, I just wanted to find out how it works. In this case, it was Panasonic TX-P42UT30E. It's an European model, placed below GT30, lacking recording and color management options (compared to GT30), but featuring G14 panel, 3D etc.
A Timewarp was performed using quite cheap equipment, on old Canon 400D DSLR, using its mechanical rolling shutter feature to record individual subframes on red, green and blue gradient, displayed on the TV at 24fps using built-in media player. In that case, it is displayed at refresh rate 60 Hz, using 3:2 pulldown, as it seems that TV can't display 24p video using 48 or 96 Hz from built-in player (so 24p smooth movie feature is not available). Made about a hundred photos in 3fps burst mode, using the shortest exposure of 1/4000 (for blue) or 1/2000 (for red and green) and stitched them all together in one big image (hence some imperfections) illustrating how a single frame is actually displayed.
On attached picture, x-axis is duration of one 60 Hz frame. y axis is intensity of displayed color, with black on the top and maximum intensity at the bottom, so it's evident which subfields are used to display various intensities of red, green and blue. Contrast was set to maximum and Eco mode was off, so TV produced maximum available brightness
Well ... it turned out that engineers in Panasonic did an excellent good job, because a really good picture coming from this TV is achieved by only several thousand possible colors PER ONE 60 Hz FRAME, as nobody noticed that. Also, I can't find expected ten subframes. There are 8 subframes for red and green, and 7 for blue - at least to display a full range of individual red, green and blue color at 60 Hz refresh rate. Also, it's evident that only a small part of combinations of that subfields are actually used, so number of total colors within a single frame is several thousand at best. Everything else is achieved by strong usage of temporal and spatial dithering, which is clearly visible on the photos (evident from the enlarged photo of one green subfield)
It's interesting that usage of subrafmes is quite different when reproducing 25 or 50 Hz PAL video, with even less possible colors. I didn't test 3D mode, but according to Panasonic brochure, in 3D modes subframes are reversed, with longest first and shortest last, to reduce ghosting caused by phosphor decay
Also, it's visible that there is still a big difference in decay time between red, green and blue phosphor, with green being the slowest.
Alex
So, in the absence of accurate information, I decided to make a timewarp of one PDP to find out. I want to point out that I made it just out of curiosity, because I'm a kind of technical guy, and not to start a war LCD against PDP. I'm quite satisfied with the TV, I just wanted to find out how it works. In this case, it was Panasonic TX-P42UT30E. It's an European model, placed below GT30, lacking recording and color management options (compared to GT30), but featuring G14 panel, 3D etc.
A Timewarp was performed using quite cheap equipment, on old Canon 400D DSLR, using its mechanical rolling shutter feature to record individual subframes on red, green and blue gradient, displayed on the TV at 24fps using built-in media player. In that case, it is displayed at refresh rate 60 Hz, using 3:2 pulldown, as it seems that TV can't display 24p video using 48 or 96 Hz from built-in player (so 24p smooth movie feature is not available). Made about a hundred photos in 3fps burst mode, using the shortest exposure of 1/4000 (for blue) or 1/2000 (for red and green) and stitched them all together in one big image (hence some imperfections) illustrating how a single frame is actually displayed.
On attached picture, x-axis is duration of one 60 Hz frame. y axis is intensity of displayed color, with black on the top and maximum intensity at the bottom, so it's evident which subfields are used to display various intensities of red, green and blue. Contrast was set to maximum and Eco mode was off, so TV produced maximum available brightness
Well ... it turned out that engineers in Panasonic did an excellent good job, because a really good picture coming from this TV is achieved by only several thousand possible colors PER ONE 60 Hz FRAME, as nobody noticed that. Also, I can't find expected ten subframes. There are 8 subframes for red and green, and 7 for blue - at least to display a full range of individual red, green and blue color at 60 Hz refresh rate. Also, it's evident that only a small part of combinations of that subfields are actually used, so number of total colors within a single frame is several thousand at best. Everything else is achieved by strong usage of temporal and spatial dithering, which is clearly visible on the photos (evident from the enlarged photo of one green subfield)
It's interesting that usage of subrafmes is quite different when reproducing 25 or 50 Hz PAL video, with even less possible colors. I didn't test 3D mode, but according to Panasonic brochure, in 3D modes subframes are reversed, with longest first and shortest last, to reduce ghosting caused by phosphor decay
Also, it's visible that there is still a big difference in decay time between red, green and blue phosphor, with green being the slowest.
Alex