I've owned a Panasonic 46pz85u, a 2008 model 46" plasma, since Christmas of last year. I love the picture, and watch all of my TV, movies, and video games in "Cinema" mode, also known as "THX" on some newer models. Cinema provides the best flesh tones, color, black levels, and noise reduction out of all the display modes. The only issue I have with Cinema in comparison to the other modes is the lack of light output. I haven't personally measured the "Footlamberts," a measure of luminescence, emitted from the monitor, but it can't be that high, even with Contrast, or "Picture" as the panel calls it, turned up to 100.
So, what am I to do when the highest Picture setting in Cinema doesn't produce enough light? Well, I finally found a post that helped me figure out that the service menu can't up the Contrast from an HDMI or DVI source, but CAN change it from an analog source, such as component cables. I'll describe this process briefly for those who either have my model, or one like it, but CAUTION: WRITE DOWN DEFAULT SERVICE MENU SETTINGS BEFORE CHANGING ANYTHING!
1. On your panel, hold down the "Vol. -" button, while hitting "Info" on your panel's controller three times.
2. Once the service menu opens, you will see the setting "Contrast" there, and, if you have a component source plugged in, there should be a value next to Contrast other than 000, and a constantly changing value next to YMAX.
3. Adjust this value using the volume control on your controller. I would not recommend turning this setting up any higher than 10-15 notches above the default setting.
4. When you're done, hit the power button to turn your panel off, then turn it back on.
There you go. I saw a post for service menu access for other models, and know that the "Info" button could be substituted with the "Recall" button on some older panels. Just be very careful when playing around in there, as you don't want to kill your panel.