It's nice if you want something inspirational to hang on the wall, or decorative, but it isn't necessary to build a bike. The actual process breaks down into steps, and normally they don't require full size plans to build from.
If you do get them printed for action, then make sure that there are some detail printed on them that will make it easy to scale the print. and these should work in several directions. dimension on the main triangle would work.i I am taking about scaling the print, so that you know they got it right. I have have several that turned out to be about 90%, and I didn't immediately notice.
It was fairly significant coin to print plans around here, so if it was truly cheap and accurate it would be well worth it.
Agree with MassiveD- if they are to be working drawings make sure they are correctly scaled before you leave the store.
FedEx Kinkos has large format printing and can be scaled up. They charge by the sq. ft. of paper used. (I think it's 75 cents.)
The only problem I see that the paper is not as durable as I'd like to be used as a working drawing (at least not how I use it) which is why I use a full size mechanical drawings on poster stock. Of course I'm old, an not fully in tune with the CAD thing.
BITD, I would draft out the head tube joints, and that was all. I think a blueprint place can be counted on to print to scale. I'm guessing that lawsuits can happen if they don't. Kinkos can be counted on to push go and hope for the best. Blueprints should be fairly durable. I think you can still get blueprints made because it's one way to get a large format copy and be guaranteed no scale issues. Would be nice if the OP would report back
I had a blueprint made once, I can't remember why. It certainly makes your design look more respectable
I was in the local Walgreen's store last week and was quite surprised to see they had a new 36" plotter in the photo Dept. Apparently they make posters to order now. Roll paper was right there and loaded. Lady said that all their store have them now. Doubt they have the range of software support that a Kinko's would...such as if your file is AutoCAD, then go to kinko's. But if you can shoot it out to JPG, TIF, or some common format, then Walgreen's could make it for you. A 36x84 inch plot would cover a larger tandem design if needed.
Believe me, the fact they are in the print making business, does not mean they will get them right. In the old days blueprints, which not great looking, were direct copies of the original made by shadowing the drawing over the blueprint copy paper. Today, there are so many ways to screw up a print, that it happens even to pro orgs that are in the drawing sales business. Whip out that achitect's rule or something and make sure, on more than one direction.
Print fullsize to PDF, then take it to a professional printer. It's rather unlikely that you can still have a real "blueprint" (white lines on a blue background) made, only slightly more likely that a "blueline or blackline" (blue or black lines on a white backround using a UV light and ammonia process) made. Both were overtaken by large format B&W printing about 15 years ago.
Note that black and white (grayscale) is far cheaper than printing in color. It's always good practice to include something that can be scaled to check the accuracy of the print.
A 15 second google search yielded two likely places: Oregon Blue Print and Willamette Print and Blueprint.
The ones I got that were bad were CAD drawings. It is so easy to push a wrong button, it comes out 10% off and it isn't noticeable until you cut a tube or two.
I don't know how they screw it up, but it could be the same as with printing on a printer. There if you print something full size, or fit to the page, it may not be obvious that there was a mistake. There are a lot of other ways to blow it.
There is also the whole paper shifts in the weather thing also. Which is why some prefer mylar.
If one just takes the measurements direct from the machine space it eliminates the complications, and saves on the cost of the print.
I am not saying this will happen to you every time. The time I first got caught was building guitars from LMII plans. They are a professional provider, and I was all in building forms for the bodies and such when I noticed that I had blown it. I build all those fixtures first. If I had started with the neck, which is what I do when I have the fixtures, it would have been pretty obvious the half scale was not 12 inches ish.