All worts will darken during the boil, but the effect is mostly a factor of how concentrated the wort is. The extracts themselves tend to be darker to begin with because they have already been through a boil and dehydration process.
AG Pilsner beers are a light straw to light gold color, and they are usually boiled for 90 minutes.
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Primary: Saison, Berliner Weisse, sLambic I, sLambic II, IPA, 70/-
Secondary: Orange Blossom Mead, Flanders Red I
Kegged: Fat Man Porter w/ 1469, Fat Man Porter w/ 005, Centennial Falcon w/ Conan, Centennial Falcon w/ Denny's, Barrel-aged Fat Man Porter, Belgian Dark Strong, Dark Mild