iP 8720 dull colors

Hello all.

I just purchased Pixma iP8720, after reading many wonderful reviews on its print quality and ability to take cardstock.
However, when I tried a first print tonight there was no setting for cardstock.
I used a matte photopaper setting, but the print was very dark, the colors not true to the original.

I was prnting an image that had been professionally printed (a tarot card from my own design) and the color difference was huge.
The blue was dull and the yellow was very flat.

I am using Photoshop CC on a Mac.

Any help appreciated.

Thanks in advance.