Proof Printing

https://plus.google.com/photos/1165...s/5802190023369826785?authkey=CIrV3tu8wM3l_QE

I have a question and hope i can get advice from printing community. I'm creating post cards with illustrations created in Adobe illustrator. I have my computer calibrated but I'm not able to calibrate with a printer since i send my work out to get printed. The colors bars are good when it prints but the final result always looks much darker when printed than how it looks on my monitor. I am not sure if its the profile I'm using or the paper but If you look closely the grays in the digital file show but on the printed piece they come out black almost. Can anyone give me suggestions on how to fix this or what i can do so my future prints don't come out looking like this?

 

When making proofs, you'll need some idea of the "dot gain" that you'll get from your chosen output. Bigger dots means a darker image. You need to set it up in Illustrator.