Hi had same problem after i used the browser, in the menu list there is a setting for Brightness/Colour, when i had it on level 3 and exited the browser it seemed the setting applied to the whole phone not just the browser so i went back into the browser and set it back to default and now the screen colours are back to normal, hope this helps.
You may have to set it to level 3 then back to default t get it to wrk
I checked that first. All my settings are OK, the screen as just lost its bite. I checked it against a friends phone who skipped the update and side by side you can see the difference. I might go back to the previous firmware.