I think you should be considering viewing distance. most times 300 ppi is recommended for prints of normal sizes,but when you start getting into fairly large prints,you may be viewing them at 10 feet away, so your ppi count can be less and still look okay. an 8×10 at 72ppi will not be good, but a 4ft x 6ft poster may look okay at the right distance. your 36×27 image at 72ppi,is the same as an 8.64 x 6.48 at 300 ppi.
Magazines and newspapers print images with halftone dots. You can see them with a loupe or if you have very good close up vision. Those haftone dots are printed in different sizes and are measured by what’s called "line screen" In order to avoid stairstepping of diagonal lines, you typically need a file resolution somewhat higher than the actual line screen resolution. The standard for that has traditionally been 1.5 – 2 times the line screen. Since most magazines print at either 133 or 150 line screen, the industry usually calls for double the 150 line screen resolution, hence the 300 dpi request for your file. Newspapers usually use a lower resolution line screen, usualy between 85 and 120 l/s, so the resolution requirements for them is somewhat lower. Most of the time this is more than what is really needed, but provides a safety margin for images that are placed at more than 100 percent in the layout application. If you are printing on a printing press using halftone separations, the barest minimum resolution for acceptable results would be a file that is the same resolution as the line screen number at the final print size. Anything less than that and you risk seeing nasty artifacts in prints. Of course, you can print at whatever you like but you’ll have to live with how it looks.
RICHARD SMYTH
I HAVE SEARCHED ALL OVER THE PRINTING DIALOG BOX FOR THE DPI SETTING. WHERE IS IT? I MUST BE MISSING SOMETHING I CAN’T PRINT MY PHOTOS AT 75DPI !! I EVEN HAD A MAC FRIND OF MINE SEARCH FOR ME AND HE COULDN’T FIND IY EITHER I NORMALLY PRINT MY ARTWORK AT 1400DPI SO I BEEN IMPORTING IT INTO iPhoto WHICH HAS THE SETTINGS THIS IS FOR PHOTO ELEMENTS 4.
I MUST BE MISSING SOMETHING
Good research!
Rob
Bob: Image resolution is in ppi; printer resolution is in dpi. Often, people use "dpi" when they are referring to image resolution and should use the term "ppi".
RICHARD: ALL CAPS IS RUDE; IT’S CONSIDERED SHOUTING.
The printing dialog box in Photoshop doesn’t have a ppi or dpi setting. You set the ppi when editing the image, using Image > Image Size. You set the printer’s dpi setting using the printer driver dialog. You don’t say what brand of printer you use; with Epson’s driver dialog box, for example, the "basic" settings don’t list dpi, just useless stuff like draft, text, graphics, photos, best photos; you need to click on "advanced", which will let you select the dpi.
And by the way, this is the Photoshop WINDOWS forum, not the Photoshop MAC forum. I have no idea how these will be displayed in a Mac.
