imac only allows mirrored display 800x600

[Face-Man]

I was wondering if anyone could tell me how to force the teachers imac to allow higher resolutions on an external display/projector. Currently it only allows 800x600 but the projector can cope with far higher. Looking at the web there appears to to be third part software out there but that also appears not to work with Lion and I'm guessing all they do is change some settings hidden under the bonnet.

[GrumbleDook]

Probably a sucking eggs moment, but you have forced detection of screens? I sometimes have to do this. What model iMac is it? Are you connecting via VGA or DVI? Edited December 15, 2011 by GrumbleDook

[iSteve]

On ours we have "iMac" and "VGA Display" when we mirror. If you up the resolution on the VGA Display, the iMac will match it or similar. If you up the iMac, this usually doesn't up the VGA Display resolution. What I'm trying to say is change your external resolution first.

 

Under mirroring situations, you can't run two different resolutions.

[dayzd]

If you're not mirroring, can you get the iMac to use the projector at higher than 800x600?