Watermark showing up too small in Aperture 3.1

Just upgraded my Macbook and am having a probelm with Aperture.

I am using the same watermark, and the same version of Aperture on both Macs, but on the new Macbook, the watermark is showing up too small.

It is not set 'to scale' and all the settings are identical.

On my old Macbook, the watermark is large and covers the bottom 1/4 of the photo.

On my new Macbook, the watermark is tiny and can barely be seen.

This has been tested using the same photo.

What could be causing this to occur?