[Terry]

Hi.
I don't know anything about how printing works. I don't need to know *everything* (as helpful as that would be), but I do need to know some basic things.

I want to make a poster for a friend of mine, 24" x 36" in size. I go to kinkos to print (they're the only place I know of), so I'm not sure what kind of printer they use there. If I were to create the image in photoshop, what would the resolution be?
(this is where I get confused)
If the picture is being printed by a 1200dpi printer, would I make the resolution 1200 pixels/inch?

And how does the image mode affect how it looks after it's printed? Does the image have to be changed to CMYK?

Any help is appreciated,
ty!

-Terry

[liv the fish]

First up, DPI (dots per inch) and PPI (pixels per inch) are not the same thing despite that people often use them interchangably.

DPI is a printer's term for how many dots of ink are crammed into one inch of space on paper. The higher the DPI, the smoother your image will appear because the dots will seem to blend together. On the other hand, the lower the quality of paper you use (Newsprint on the low side, some Glossies on the the high end), the fewer dots you can use. This is because ink/toner spreads out as it hits the paper (for toner the spread is from melting from the heat of a fuser). For this reason, Laser printers usually work better on most papers than Inkjet printers, as far as cramming more dots in an inch at least. Kinkos will probably have a Laser printer but you should ask first.

PPI is a measurement of how many pixels are packed into an inch on your monitor/T.V. It may be easier to think of pixels as a dot of information instead of as a dot on your screen. If you set your PPI to 300, that means you have 300 dots of information about your image in every inch of your document. But, 1 Dot of information does not equal 1 Dot of Ink.

Usually, if you set your document to 300 ppi, that's enough information for most highend printers. For a poster you may want to go higher. You should ask Kinkos what the mechanics (printer talk) are for good looking poster images. Make sure you find out whether they're talking about DPI or PPI and ask how much PPI you need to set it at and how high the DPI can be for that setting.

I work with a lot of newsprint and program ads and we almost always set all color images to 300 PPI. Very rarely do we go higher and it usually maxes at 600 PPI. Most times I don't bother finding out the DPI (or LPI=lines per inch. Ack! its another printer term) as the printer has a default setting they use.

For image mode, you should make it CMYK for the 4 colors used in 4 Color print jobs. One of the few times it'd be safe to leave it in RGB is if you're printing to an Inkjet printer. Commercial Inkjet printers are designed for people that don't know or care about the difference, so they work just fine with RGB. If you leave it in RBG some of the colors may not print correctly in the CMYK process. If you're image is B&W, I'd suggest making it Grayscale to lower the amount of information the printer has to process.

Good luck with it,
Brian aka l.t.f.

[ October 16, 2002: Message edited by: liv the fish ]

[B0b]

why post on here if your unsure?? try picking up the phone and talking to them to find out what format they want your disk in..
and creating the whole poster in Photoshop? thats a 222Mb File.. without layers

[ October 17, 2002: Message edited by: B0b ]

[Terry]

Thanks for the great info Brian, you answered all my questions! Good to know there are 'some' nice and helpful people around here.

-Terry

[NeoFun]

Oh, you might want to stay away from Kinkos since they charge so much. I use EZPrints.com and photoaccess.com Give them a try and see if they work.

Brian- Thanks-- all that printer info was a bit of a lesson for me as well!

[Terry]

Yeah, kinkos charges $40 for an 18"x24", and $80+ for a 24"x36". I'll check out those sites neo, thanks for the info.