Originally Posted By: dparm
I have an image file on my computer that is 2440x1820, 24bit, 300dpi (5x8"?). What's the largest I could safely print this onto photo paper before the drop in quality becomes noticeable?
It's a very crisp high quality photo, very little JPEG noise/artifacting.
Hi dparm,
Your image file is 2,440 x 1.820 pixels, which is 4.4 MP (mega pixels). Your image file does not have any "dpi." Image size is measured only in ppi (pixels per inch).
For a print in photographic quality, 300 ppi is usually recommended.
Your image, sized for printing at 300 ppi would be very small: A 2,440 pixel wide image at 300 ppi is only 8.1 inches wide.
If your printing service can up-res your image well, then you may be able to get away with image resolution as low as 150 ppi:
2,440 :150 = 16 inches. Is 16 inches wide enough? If not, you will simply have to stand back when looking at the print.
Regarding the print:
Image resolution (ppi) and print resolution (dpi) must not be confused. Pixels are a variable, because their size changes with the size of the image. Dots per inch are exactly that: a fixed measurement of the number of ink dots that a printer head squirts on the paper.
Print resolution should be twice as high as image resolution for best results. That means, if you have an image that is x-inches by x-inches at 300 ppi, you should print this image printed at 600 dpi or higher. Do not worry about printer resolution. Even the cheapest consumer inkjet photo printers have a native resolution above 600 dpi.
If you have your images printed with a Fuji Frontier (RA-4 process) machine, don't worry about print resolution at all. The image is written with a laser on the photo paper, which is then processed conventionally.
Cheers,
-J
