Second Monitor Looks really bad

I just bought a MacBook Air and I am trying to connect it to a monitor using HDMI with the Thunderbolt cable. When I do this it seems to work, but the picture quality is really bad. Everything has a grey feel to it and makes it really hard to read and work on. This monitor works fine when connected to via HDMI from another laptop. I have tried connecting it via HDMI using both Windows and OSX.

Does anyone know how to fix this? Thank you.

It sounds like you're not using the proper adapter and or cable from the Thunderbolt output to the monitor. The Thunderbolt port on your MBA is backward compatible to the MiniDisplay Port standard.

Check with monoprice.com to see what adapters and cables will work. Also, not all monitors will work from the Thunderbolt output even with an adapter.

Here is the adapter i bought, and how do i tell if the monitor i have won't work?
For only $5.70 each when QTY 50+ purchased - Mini DisplayPort | Thunderbolt® to HDMI® Adapter w/ Audio Support | Mini DisplayPort to HDMI / DVI / VGA Adapters

That's the correct adapter. As far as which monitors will work.... the only one that I'm sure will work is the Apple Cinema Display. I really don't know how you can tell except to test it. If the monitor is new, perhaps you can return it. By the way, you're not the only one who is having a difficult time with this, other users have likewise stated the same problem. And I believe MacWorld some time back had an article that addressed this.

The Apple Support Forums are also loaded with like questions, for example: LINK

Huh well that sucks. The monitor is newish, but I can't return it. Does DVI or VGA work?

You don't want to use VGA as that would be analog. And if you go with DVI that would mean you'll have to purchase another adapter to test it with.

Unless you buy a monitor that specifically states it supports Thunderbolt it may not work. I hope you can use your new monitor elsewhere.

Are there cheap monitors out there that support Thunderbolt? I didn't even realize there was a difference between thunderbolt hdmi and regular.

They're all expensive. I just checked out the Dell site which has the new Dell Thunderbolt displays. Nothing out there that sells for what you and I can afford.

Why don't you try a MiniDisplay Port DVI adapter to DVI cable to your monitor to see if that works OK? Just make sure you buy the adapter and cable from a vendor who accepts returns. If I remember correctly MacWorld seemed to recommend doing it that way.