Can you clarify what you mean? A screenshot would be helpful.

• How do I create a screenshot of my problem?

If you want to change the background of the tabs, you can install either a theme or a complete theme.

• https://addons.mozilla.org/firefox/themes/solid/
• https://addons.mozilla.org/firefox/complete-themes/

If you want to change the default page background color,

1. Click the ≡ Menu Button and choose Options.
2. Click the Content icon.
3. Click the Colors button.
4. Next to Background, click the swatch and pick a color.

Go to the Mozilla Add-ons Web Page {web link} (There’s a lot of good stuff here) and search for what you want.

Here is one' NoSquint {web link} NoSquint allows you to adjust the text-only and full-page (both text and images) zoom levels as well as color settings both globally (for all sites) and per site.

Many thanks, No Squint did the job. Background is now a light grey which is much easier on the eyes with my bright IPS screen.

In NoSquint's settings, you'll probably want to leave the "Disable background images" option unchecked. Some sites — for example phpBB forums like MozillaZine — use background images to display important information, like text for buttons. In these cases, if background images are disabled, certain site features will be usuable, or site navigation will be outright impossible.

Gingerbread Man, thanks for the warning but as I didn't understand exactly what it meant I left it alone. What I have noticed though is that No Squint seems to treat some images / graphics differently to others on the same page. My local weather map ( http://www.bom.gov.au/products/IDR043.loop.shtml ) which is a looped time lapse of four individual radar images is not displayed when No Squint background grey is enabled while the rest of the screen seems OK. Also http://www.dpreview.com/ 'loses' some images but not others on the same page when No Squint is enabled. I'm seems that No Squint is operating on web pages I visit but doesn't affect Firefox itself as when a new tab is opened it is standard white. Fortunately it is very quick to turn off which I do if I see blank areas on sites I visit. Cheers

Did you use the No Squint global setting? If so, turn it off. When you go to a site, open No Squint and adjust the setting for that site. I only use global for screen size, and set each site with it's colors.