Awinphoto makes many more good points.
Back when my first digicam was a Canon PowerShot A20 I managed a lovely, very colorful shot of a sports activity which ended up on the front cover of a small national magazine. This would not have happened without the combined skills of 3 people. (I count myself as one of them)
I first had to uprez and sharpen the tiny 2MP shot to minimum screening rez as requested by the magazine's printer (180 lpi if I remember correctly). Before submitting the image I conferred with a friend in the graphics industry with a lot of experience. She had a quick look at the image and altho she liked what I'd done with it, took it and converted it to CMYK and did a little color adjustment to compensate for printing dot-gain, based on her experience and the kind of paper it was going to be printed on. The colors now looked off to me but I submitted the image, the magazine printed it as supplied, and it looked great!
With all that in hindsight so long ago what comes to mind is that printing, in all its various forms, is as much an art form as photography, with a huge number of variables. Hence, until you're doing all this on your own, find and work with a printing service that's familiar with creating the kind of output you want from the kind of files you supply.
I learned a lot from the first shop I found that was an art-quality printer and did a fair bit of my work there. It cost me a lot, but they worked with me and created beautiful prints from my sRGB files. As I learned more about the process I was able to take advantage of lower cost shops for some kinds of work by knowing their equipment and their procedures and adjusting my output files accordingly.
If you want your first big canvas print to go well, I'd suggest finding an experienced art-print shop to help you thru it. It may cost you more.
Then there's the whole to-varnish or not-to-varnish your canvas.. I get mine varnished by someone who's done a lot of work and research on this aspect. Resulting finish is very tough and durable, colors are great, and I don't have a mess to clean up at my facility.