Recently I started drawing again. Now I am completely worn out tonight because I wrestled with a mech drawing for a whole day. And that's just a front 3/4 quarter view. I have to draw a rear view and design the weapons tomorrow. My skill level is nothing to brag about, but I am thinking about creating a mini portfolio using the Costco photo service. Here's how I do it. I would modify the size of canvas and images to fit 4 by 6 inch photo. For most designs I use a tabloid size paper because I can put in a lot of details and also I can do some decent line quality. Well, after I scan my line drawings in Photoshop then I can modify the canvas size to 12 by 18 so that it can be shrunken to the photo size.
And the artworks will be fit nicely to the photo albums. You can take your photo album with you and show your works to people. I wonder anyone else tried this kind of apporach.
PS. When I draw a mech, I start from a piece of letter paper folded into half. I have trouble drawing directly into the tabloid size paper because I can't get the proportion right. For a right proportion I have to draw on a smaller surface. I use Copic markers and a black Tombow brush marker to lay down the rough proportions, then I go to a local Office Depot to enlarge the image by 200%. Then it fits to the tabloid paper. Then I use my lightbox and put a printing-quality cardstock paper on the copied image. I use a pencil to tighten up the details and stuff, then I ink the pencil drawing with a Prismacolor pelt-tip pen. The process sounds cumbersome but I am definitely getting used to it. What I usually do is to draw many rough drawings in one sessions so that I can trip to the copy shop just once in a while.
And personally since I don't know the prices there, you could consider putting money to a printer and just print your own images small at home and do the test runs with it.
I do most of my printing through a photolab, but I'm wondering what you want to use the portfolio for. If it's for a gift or a souvenir, fine. If it's to use for reviews or interviews, I would either wait to the last minute or use a format you can modify regularly. Because your most recent pieces will most likely be so much better than the older ones that your book will be outdated within 2 months.
Well, I am working on a few mechs so it will take a while to actually print it on the photo paper. But I think it will work.