Today I toke I shot at calibrating a client's monitor, a Panasonic BT-LH2550. I got a little stuck on the initial display setup process.

The thing is I first adjusted the brightness and contrast with the help of the images provided by Light Illusion. But when I measured the luminance of the display it was way too high, something like 200 nits. I then had to completely reduce the backlight to zero to get around 100 nits (my goal). Is that normal for a display to be at 100 nits when the backlight is at zero? In my previous experience, with my own FSI CM240, 100 nits equals a backlight setting of around 29.

And what is best practice here in the order of operations. Should I have started with the backlight and then adjust brightness and contrast?

If anyone has had experience calibrating a similar display please share some of the proces if you like.

Thanks!

Different displays use their controls in different ways...
There is no 'set' rules.
But, as a good rule of thumb the Backlight is a often the best control for overall brightness.
Often Contrast and Brightness are digital controls that cause clipping.

See: http://www.lightillusion.com/manual_calibration_idiots_guide.html

That guide should help.

Steve