Quote:
Originally Posted by dcclark
Just to reiterate, because I feel strongly about this:
300 DPI is NOT a magic number! It's just a random value which someone once said was optimal. You can print at any resolution above 100 dpi and nobody will know the difference unless they're smelling your photo.
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If we are going to be typing in bold I supose there are a few fundamentals that need to be addressed. First of all there is the differece between PPI and DPI.
Pixels Per Inch (PPI) is how the resolution of a digital file is measured. Your statement above therefore refers to a PPI of 100 being acceptable.
When ink is added to the paper the printer (if its an inkjet) will create a certain number of
dots per inch (DPI). Dots do not equal pixels. Your print quality is dependant on how the pixels in your image have been converted to dots. This is either guessing what colour to make the extra dots or reducing multiple pixels to one dot. Printers will print at a set number of DPIs regardless of the number of pixels in the file.
It is nowhere near as simple as saying my image has 300 PPI, therefore it will print OK at 300 DPI, nor is a simple as saying a 100 PPI won't print at 600 DPI.
Moral of the story... Printing is a very complex thing indeed. If you are doing it at home then trail and error may be involved. Using a lab? Ask them lots of questions and ask them to check your file will print OK before you hand over the cash.