Topic awaiting preservation: printing dpi

not sure if this belongs in Photoshop or here...anyways I am trying to import images from Photoshop to Illustrator (in order to print) and have a question regarding resolution. In PS under image > image size > resolution, what do you suggest as the highest resolution can I set before the file size is too large?

Maybe a low resolution could be the reason why my image is printing out pixelated...I dunno.

-CRO

Hmmm. Don't know what qualifies as "too high", but if this is going to be printed on a press, a good rule of thumb is 2-2.5 times the line screen...That's for CMYK on like SWOP coated and uncoated...Newsprint is a different scenario I think...Usual line screen is like 150, so you should be save with a 300 dpi file, provided you don't scale it up or anything in illlustrator.

Woah! I think that Jeni should make something like a Tut on printing, color and all that.
She's just great......

Here's much more than you probably were asking for, but anyways ...

OUTPUT/PAPER -- TYPICAL LPI
screen printing -- 35-65
laser printer/photocopiercopier or matte laser paper -- 50-90
laser printer/photocopiercoated paper -- 75-110
quick printer uncoated or matte bond paper -- 50-90
quick printer coated paper -- 75-110
offset printing newsprint -- 60-85
offset printing uncoated paper -- 85-133
offset printing coated paper -- 120-150 +
high quality offset or gravure such as glossy color magazines -- 150-300

Got the above from about.com at http://desktoppub.about.com/library/weekly/aa101800a.htm?terms=resolution
There's a good five pages or so of basic stuff about various resolution terms there.
Also see: http://www.dtp-aus.com/dtppream.htm
There are a whole bunch of links I had found about a year ago when I was looking into getting out of the military and into the graphic design/desktop publishing field. I was doing some hot and heavy research into what the business was all about and what all the terms mean. If I can find that list of sites again I'll post it. Hmmmmmm, where did I leave all that ...

BeeKay
Murphy's 50 Laws of Combat Operations
15. Teamwork is essential -- it gives the enemy other people to shoot at.
19. Make it too tough for the enemy to get in and you can't get out.

Whoa! Good stuff.I am a newbie to print media, so its gonna take me a while to read thru all your links and such.. I have to get in touch with the printer to see what format they want the Illustrator file in.

Thanks a bunch.
-CRO8

Yea! Thanks from me too even though I didn't ask....I'm trying to learn everything I can about both print and web design and bookmark every resource I can get!

Just a note that if you print something to an inkjet print, it is generally reckoned that you need 60dpi for each ink (hence 360dpi for a 6-colour inkjet like a nice Epson), and preferably another 60dpi for luck, or what we might call internal errors.

For commercial CMYK printing, if you print at 150 lines per inch you need a minimum picture resolution of 300 dots per inch (really pixels per inch) and preferably 330. Hence at 175lpi, which I often use, I make sure my tifs are 400 or 450 dpi S/S.

But I don't know why!

Does anyone know the reasoning behind this relationship between lpi and dpi?

quote:

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if you print at 150 lines per inch you need a minimum picture resolution of 300 dots per inch (really pixels per inch) and preferably 330

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This is misinformation to what I've been taught. If it gives you the results you need stick with it, but I'm lead to believe that anything over 2x the line screen is not only a waste of disk space and a drain on RIP efficiency, but will actually soften the image. This from Dan Margulis (Color Theory ListServe, author of Professional Photoshop 6, and a gifted if opinionated teacher), my hero in all things pre-press.

Anyone with actual press room experience want to weigh in? I know you're out there! jstuart? Tommy?

Steve is technically correct 300 dpi is slightly overkill. I all realy depends on you output device. Basicly 300 dpi is the standard most printers go by in the US, it is a happy middle ground producing acceptable results across many different process and work flows.

basicly 300 dpi is 2 times the LPI for a 150 lpi screen output on a 1200dpi imagesetter.

150 LPI is the smallest size dot you can produce at 1200dpi and still get 255 shades. Most of the original imagesetters were 1200dpi and there for 300 dpi became the defacto standard.
Now I cant remember the fromula where the value of 2 times comes from i will look later. But basicly it worked out to 2 pixels on image for every one dot on the imagesetter any more was though unnecessary some expanded it to 2.5 just to be on the save side. I think 2.5 is the value sugested in one of my old Linotype, Hell or Scitex manuals who produced some of the early rips and imaging systems.

The most important thing is to consult with printer to find out what they require.

jstuartj

I'm often surprised at the results with lower res stuff, but I've never really seen a need with any printed piece I've done to go over 300dpi. As a general rule of thumb the bigger the format the lower the dpi, i.e. 300 dpi for business cards/postcards/etc., more like 150dpi for posters or other media designed to be viewed from a bit of a distance, etc.

jstuartj has the simple answer tho, ask your printer. They're generally more than willing to help, know their stuff, and will save you a lot of time and pain. And if they're not helpful go get it printed somewhere else

Chris


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