Q: Do the recommended pixel levels contained on the iphoto help page TS1135 apply to single prints or to apple books. The rate for A4 ... Do the recommended pixel levels contained on the iphoto help page TS1135 apply to single prints or to apple books. The rate for A4 images is 1754 X 1240 pixels. more
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Dec 22, 2014 10:39 AM in response to b.wilderedby Kirby Krieger,The widely-used measures are:
- 300 PPI for sharp hand-held print, examined closely but without magnification.
- 200 PPI in a pinch. No data to spare, but skillfully-handled (sharpened) can be as good as 300 PPI. Most people won't notice a difference between 200 PPI and 300 PPI
- 150 PPI if you must. Effectively the lower limit. Difference will be visible to all. Can still be made to look good, but requires careful "up-res-ing".
These numbers are independent of the type of printer or the make or model of the printer, or the use of the print.
Of course, if the picture is being hung of a wall and not seen closer than arms-length, than those numbers are too high. It depends very much on the viewing distance. (The billboards on the roof of the former light-industrial building where I keep a studio are printed at a PPI that is less than one*. The images and letterforms on them look sharp from the highway.)
A4 is 8.27 in × 11.69 in. The rest is arithmetic.
*[figure corrected]