We are using web pages with no or old DOCTYPE as in an excerpt like this:
<html>
<head>
<title> TEST </title>
</head>
<body background="../images/dummy.gif" bgcolor="#FFFFFF" text="#000000" alink="#001080" link="#001080" vlink="#801080"
marginwidth="0" marginheight="0" topmargin="0" leftmargin="0" >
<div id="mainbody">
<table width="980" border=0 cellpadding=0 cellspacing=0>
<tr>
<td height="20" align=left>
<font face="Arial" size=-1 color="#101010">
The quick brown fox jumped over the lazy dog
</td>
<td>
</tr>
</table>
</div>
</body>
</html>
On IE9 the text is a crisp Arial font, pretty much the way the system displays the font.
If I change the doctype to
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
the font rendering changes sightly but noticeably, the font becoming a little more weight/bolder with less crispness (if you try this, save two versions of the demo html, one with the old and one with the new doctype). This happens regardless of zoom factor.
What would I have to do in regard to font tags or css styles to get the same rendering as before?
In “Standards Mode” (which you trigger with a standards-conforming
doctype), IE 9 applies more advanced font rendering technologies than in Quirks Mode. There is no way to avoid this, except by staying in Quirks Mode. The modern rendering works generally better on modern display devices, but it affects text width a little, among other things, so it may ruin attempts at pixel-perfectness.