I have been asked if I could print my work from Photoshop on a large scale (poster size - printer shop?) and I have no clue how to do this. Any help welcome, any tip, anything...

Well first off ya need a large printer... Check out your dpi and print size using the menubar at the top Image>Image Size. All pertienent info is there. Make sure you're at least 150dpi (or ppi) Next it's on to File>Print Options. The config options will vary depending on your printer.

Thanks for the tip. I have a good printer and I usually print at 300 dpi and over from the PSD files. What I meant was to print the files a least on A0 size for a display. So if I take my files to a printing shop, depending on the size of printers they've got, they should be able to print on a large piece of paper?

You bet. And any thing over 300 dpi is overkill. 150 is standard. 300 is used for art plate reproduction.

the printer I use is 600 dpi... so it's not worth over 150? Thanks for helping me.

Ok... 600dpi (dots per inch), as far as your printer goes is not industry standard. Different dots. By all means print at the highest resolution your printer will print, but create at 150.

Ok your best bet would be to print from either Freehand or Illustrator. With either one, you can get very exact for printing. Speaking from personal experience, photoshop can get wonky sometimes when printing, even with exact settings. Standard commercial printing is 300 dpi. A lot of commercial shops refuse to print any higher. As for creation, create as high as you want. If you look at The Grudge in my gallery, thats a 600 ppi image. Reason I made it so large was just in case I wanted to enlarge it later on, and because I wanted to put as much detail into it as I wanted to. Anything less than 150ppi aint too shit hot. Anything above is fine. Working at 1200 ppi is fine, and not overkill if you wanna put that much effort and detail into it, but printing over 300 dpi won't make a huge difference (though it is noticable on closer inspection). also, just in case, ppi= pixels per inch, for on screen. dpi= dots per inch for printing, and each dot doesn't actually replicate each pixel.

To clarify that... Printing dpi has to do with density and extrapolation . 150 dpi is more than adequate for printing information. the printer will fill in the rest. We can't really prercive anything above 300 with the naked eye. Whereas slynky's method merrits, it's not nessacary if you know what size you want to print at. But it's good to leave your options open. A greater dpi will allow to to enlage without pixelation.

I regularly have to print images and posters on a large format HP printer (44" width X up to however long the roll is). Everthing that goes to that printer is optimized in photoshop at 150 PPI, then the image is brought into one of several programs. (Quark, PageMaker, Illustrator) These are to get the margins and exact placement correct. (as Slynky said Photoshop can get wonky) However, if you are outputting to a dye sublimation printer, then there is a visable difference between an image at 150 PPI, and the same image at 300 PPI. anything that goes to our Dye Sub is at 300 PPI. I am not sure how large you want to go, but if it is under 16" X 20", you might want to check and see if any color labs in your area are using and LED Print System. These take your digital file, and expose it on photographic paper that is processed in traditional chemistry. It is not cheap, but the prints I have had done this way are outrageous. They will want your file at 300 PPI also.

Some time ago I printed on see-through fabric and the printer guys said they only needed 10 Mb per square meter! That was approx. 43 dpi. When I saw the output it was crisp and clear, even the logotype I put in, the letters having harsh lines. But it hints to another connection to the 'naked eye' thing Impudicus mentions: The larger the output, the smaller your image resolution (and print resolution) can be. I am certainly no mathematician, nor very good at it, but at some point there must be a balance between resolution and how large the output is, which has to do with the fact that nobody looks at a 70x100 cm poster at the distance one looks at an advertisement or book cover. So the further away you look at a printed medium, the lower the resolution can be. Something like: Image resolution = 300 divided by (looking distance in cm divided by 30). Oh no. I shouldn't try anything like this. This understanding helped me through several nights wrestling with 900 Mb layered Photoshop files on 200 dpi which were impossible to work on (on a Mac G3) when they were 300 dpi (the night before). For 70x100 cm posters 200 dpi proved to be enough. Only if you stand too close you will mention some lack of detail. Detail you won't see after all if you look from the proper distance. Mmm. Not a real addition to this thread. Just that it helped me a lot to discover that I can make REALLY large stuff on my computer. Because of the human eye and clever interpolation of modern printers as well.

Another way to increase printed resolution, work larger than your printing size. This is how printed artwork on book covers, illustrations, and comic books comes across so detailed. This is obviously more difficult on large scale images, And might be more relevant to the editting and printing of physical artwork, but it may help someone out there. Examples: When creating/editting for a 4"x5" final image, I start with an 8"x10" original, thus automatically doubling the visual resolution. final output of 8X10 @ 300dpi = original of 16x20 @150dpi final output of 16x20 @ 300dpi = original of 32x40 @150dpi or even: final of 16x20 @ 150dpi = origanal of 32x40 @ 75dpi You don't have to double the size necessarily, but I would recommend at least a +50% (and I heartily recommend keeping your math simple, you've got enough to think about). In general the computer understands that there is no difference in the relationships as far as processing goes. But I've found that the mindset involved (Draw bigger for tighter details) goes a long way to improving your finished prints. Joel Talacko joel@moonhowler.com

if you send that native PSD file to a print service shop
they will most like save it out as a tiff and print it out of quark at the size that the work order calls for