The picture is very dark and it has a new bulb

Unfortunately, this is not an easy diagnosis. It could range from being an issue with the brightness level (which can be accessed from the menu) or an internal processor defect.

First access the menu and verify the brightness levels and contrast levels.

Next, make sure the problem isn't in a single input by changing the inout of the component that you are viewing. Component cable inputs are notorious for going bad so try an HDMI if one is available or even a basic composite cables will work for diagnostics.

If the picture is still dark after this it's probably a processing problem and will require professional maintenance.