Is this an existing image or one you are going to create?
If you are creating a new image and know the ultimate physical size it needs to be (say, 4.25×5) then you would specify that size and a resolution when you create it. If this is after the fact and you need to change resolution you would go to Image Size, check Resample and set your new resolution.
However, if you are increasing the resolution, Photoshop makes up the extra pixels and the result will not be as sharp. Unless you know specifically the final size/resolution, it’s always better to start out bigger than you think you will need and then make a copy and resample it down to the size/resol you need.
wrote in message
CraigM wrote:
I think you are confusing resolution and halftone line screens. Halftone priting screens are measured in lpi (lines per inch) or how many rows of dots in the printed image there are per inch. Resolution is measured in
dpi
(or ppi) and is measured by the number of dots (or pixels) in a given
area
within a bitmap (usually per inch).
Most newspapers are printed at an 85 line screen and magazines are
typically
133-150. A rule of thumb is that the resolution of your image should be twice the line screen it will be printed in. So, for a newspaper it
needs to
be 150dpi and for a magazine it would need to be 300dpi.
In Photoshop the resolution of your image can be found at Image>Image
Size.
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… that when I send something to be printed, it’s corrected for printing in the format required by the publication. For example, most newspapers are printed at a line screen of 150 dpi (dots per inch),
and
most magazines at 300 dpi. How do I make sure that the dpi is set correctly? I’ll be sending most stuff to print in QuarkXPress documents, with TIFF images that have been Photoshopped.
Okay, so how do I set that? Do I just look at how big the final design is to be (say 4.25 x 5.5 inches), and do the math based on the number of pixels? Do the pixels translate to dots when it goes to print?
