I worked today on PSD to XHTML conversions and noticed that, only firefox work well with negative letter-spacing. So, I had to adjust space between letters a little … less than 1 px, so I placed in my css “letter-spacing: -0.04em”. This work only in Firefox (I have installed FF3.0 ). I made some tests and here are results:

Firefox 3.0

letter-spacing: -0.04em; – work
letter-spacing: -0.5px; – work
letter-spacing: -1px; – work

Safari 3.1.2 / Chrome 3.0
letter-spacing: -0.04em; – ignored
letter-spacing: -0.5px; – ignored
letter-spacing: -1px; – work

Opera 9.6
letter-spacing: -0.04em; – render it as -1px
letter-spacing: -0.5px; – ignored
letter-spacing: -1px; – work

Internet Explorer – test via IE Tester
IE8

letter-spacing: -0.04em; – render it as -1px
letter-spacing: -0.5px; – render it as -1px
letter-spacing: -1px; – work

IE6&7
letter-spacing: -0.04em; – render it as -1px
letter-spacing: -0.5px; – ignored
letter-spacing: -1px; – work