For when you need a different logo for print than screen - either a higher quality, different colour etc. Use this in print.css. Doesn't work in IE7 but IE7/print is a bit of an edge case

Different colour logo in print.css

/* for <a href="#" class="logo"><img src="..."></a> */
 
.logo,
.logo:before {
  height: 75px;
  width: 275px;
  display: block; }
 
.logo {
  position: relative; }
	
.logo img {
  display: none; }	
		
.logo:before {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  content: url('../img/logo-print.png'); }