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I was recently reading a wikipedia article on what is the difference between the DPI (dots per inch) and PPI (pixels per inch). I've came up to the point that the DPI value is relevant for the printer and the PPI value is relevant for the monitor.
As I'm not even a hobbyist photographer, I wonder, if a single image can store both DPI and PPI in the image's metadata? (so i.e. the picture would have different physical dimensions (in inches) on a monitor and when printed). Is this a common practice with pictures?
colemik
Posted 2012-03-17T22:49:56.430
Reputation: 1 414
Image resolution in DPI
thank you. This is actually interesting. Should I interpret your answer like this?: the picture's exif data contains two values: a DPI of the picture (how many inches should the picture be ~in length if printed) and a PPI of the CCD sensor inside the camera (how many points (pixels) the CCD sensor can catch on 1 inch of sensor's surface). Only the DPI value describes the picture, so a picture exif data cannot store both DPI and PPI values (or, rather, both DPI and PPI are always the same thing in the picture exif data context - the DPI of the picture) (~DPI == PPI). This makes sense ;) – colemik – 2012-03-18T03:17:06.730
focal plane picture: http://personalpages.manchester.ac.uk/staff/p.dudek/projects/scamp/focal-plane.gif
– colemik – 2012-03-18T03:27:43.190yup - and in the context of PPI on displays its probably based on your resolution/size rather than the original photo – Journeyman Geek – 2012-03-18T05:00:32.757