The Philips 190S1SB has a maximum contrast ratio of 25000:1. That's 100% less contrast ratio than the most frequently found dynamic contrast ratio of 20000000:1. The worst contrast ratio of all similar spec flatpanel monitors that have been around for around the same time as the 190S1SB is Mega Contrast and the best is 100000000:1.
Other LCD screens that have a 25000:1 dynamic contrast ratio currently available which you might want to consider include the Philips 17S1SB (£57.52) which has a better Rating.
If the contrast ratio of this Philips flatpanel monitor is not high enough for you then you might want to consider the Viewsonic VA2046 (£107.96) (1000000:1 and higher rated).