Need help with Dual External display setup with Macbook Pro and 27" display

Hi all

I have a user in my Marketing dept. with a mid 2010 15" Macbook Pro and he currently connects to a 27" Apple display (older version, not the Thunderbolt version) to do his creative design stuff. I need to set him up with an additional external monitor. The reason is that some of the images he produces on his MBP + 27" display show up differently on his setup than they do on the HP or Dell monitors we use. We can actually see artifacts on the HP & Dell monitors that do not show up on Apple display or MBP display. So when he publishes these images to the web, users see things he's not currently seeing. We've tested and verified this by setting up a HP monitor with a Apple mini display port -> DVI adapter connected to his MBP and confirmed that it is true. We also setup another Mac (13" Macbook Pro Retina) connected to the 27" while his 15" was still connected to the HP display and compared the same image side by side. The HP showed artifacts where the 27" and 13" retina displays did not. Very strange but it's true. So we're trying to come up with a solution to add an additional display to his setup. The problem is that he has a single mini-display port on his Mac, so we're probably looking at a USB 2.0 -> VGA or DVI converter to add that 2nd external display. I know the performance won't be great but these are just static images so I'm hoping that will be OK and at least let him compare the images he's working on on the 2 displays.

Can anyone suggest of an adapter or any other ideas to look at and try?

Thanks all for the help and suggestions.

 

One of the main reasons for keeping the Apple display is the over all size of the work space it provides. He does process some large images and it gives the him a lot of screen real estate to work with. Going down to a smaller 22" monitor (1920 x 1080) or even 2 for his primary screen/s would probably impede his work more than adding a 2nd display with the 27" display.