Does a rel canonical link remove all SEO value from the page

Question

I have a site maintained for a local company that does quality content for on-site blogs. I'm in the process of building another website targeting the new region. I want to pull in any content from the old blog and create a new blog for it.
Then of Corse I will  add a rel=canonical link back to the original blog in order to ensure I don't get any duplicate content penalties from posting the same content across two separate domains.
My question is whether adding that rel=canonical link will eliminate the SEO value of that content being posted to the new website? I'm more concerned about whether using a rel=canonical on the content would eliminate the secondary SEO benefit of having relevant, frequently updated content on your website, due to Google being essentially "blind" to the duplicate content.