Do you view what you want to print prior to printing - What does it look like in the 'Print Preview' ? Have you selected the correct printer or is another default setup? Are you using colour or black and white mode ? What 'scale' setting are you using? After checking the 'preview' - at bottom click on 'Print using the system dialog' link and it should offer the Print Settings window. Maybe you have a preference set up to use a lower quality draft setting or economy setting or save ink setting. Something of that type of set up for the printer when using via Thunderbird.