The Acer H236HL has a maximum contrast ratio of 100000000:1. That's over five times the contrast ratio of the most common dynamic contrast ratio of 20000000:1.
A 100000000:1 dynamic contrast ratio is in fact the best contrast ratio amongst all similar spec PC displays that were released more than two years ago.
Amongst similar types of flatpanel monitor the worst contrast ratio is Mega Contrast.
There are a number of other PC screens that have a 100000000:1 dynamic contrast ratio currently available which you might want to look at including the Acer G237HL[plb_2266292_price] which has a better Rating.