Sloppy Positives

[KENTDESIGNS]

When I'm printing 18"X24" positives at my local blueprint shop they are almost always a little off. Usually the horisontal reg marks are spot on, but the vertical marks are up to a 1/4" off. In other words, my positives are either longer or shorter than they should be. Is this common on a large format printer or does this place just suck? These are PDFs on both bond and vellum.

[strawberryluna]

That's such a drag. You should double check them before you leave the place from now on and show them how they don't match up.

Before I was printing my own films at home, I'd get them done sometimes at Kinko's and they wouldn't match up, so I'd have them reprint. It can happen sometimes when the printer gets too hot while printing, which can change the size of the film slightly, but slight size changes matter in screenprinting. So, I let the printer rest for a couple of minutes in between films.

I'm not sure why else it can happen though, I'm sure one of these other smarties has better advice.

[steve w]

yes, it's common.
the alternative is expensive film output.
deal with it

[mixtapenostalgia]

we had issues with the place that does ours. Ask them what compression they use. If it is a blueprint shop, it most likely uses CCIT4 Fax Compression (that's what most blueprints are)

If you have IRFanview (imaging program for PC), you can save your black and white tifs as ccit4 compression. That fixed all our problems.

[jayryan]

i'd go see a band called "sloppy positives".

[KENTDESIGNS]

PDFs printed 11"X17" on a Xerox are always perfect, so I'm pretty sure things are fine on the file. Sometimes 1 or 2 of the 18"X24"s will match up but it's never the most important ones. (like the black screen) The reaction is always the same...

"Um...we printed them." or "That's the file you gave us on the disc." and even "They look good to me, what's wrong with 'em?"

[mixtapenostalgia]

things maybe perfect with the file, but they won't rush to agree with you that their compression and post script on their plotters isn't working. that's why i'm saying just ask them what compression they are using, and i'm fairly sure it will go away.

[KENTDESIGNS]

Sounds like a plan. Thanks for the tip.

[Iron Canvas Studios]

that compression thing is good to know.

[Andymac]

any positive made with heat (laser/vellum) on an unstable medium will probably stretch or distort. the bigger, the more chance of it happening.

Inkjet through a decent machine will give you a more accurate (less stretched) print

some of this has to do with the drive mechanism too, the material can slip slightly as its being printed.