If there is no change in the number of pixels altogether then all you are changing is numbers in the file header there is no change in the image data itself. I find that my 5 Mpx Olympus image size is stated as 72 ppi, however I resize in Photoshop without changing the file size to 240 ppi to get an 10"x8" print. I have found that 150 ppi is quite sufficient for a normal print. So I can print bigger than 10x8 inches without interpolation. -----Original Message----- From: owner-photoforum@listserver.isc.rit.edu [mailto:owner-photoforum@listserver.isc.rit.edu]On Behalf Of Robert G. Earnest Sent: 14 October 2002 12:05 To: List for Photo/Imaging Educators - Professionals - Students Subject: Re: file formats chandler wrote: > Sorry, but this is a meaningless question, based > on meaningless nonsense. Who shit in your Sake, Chandler? Let me rephrase the question. I have a Canon G2 which I have been very happy with. My purposes for the camera have never once included actually printing one of the images. It had occurred to me that 72 ppi was probably not the optimum resolution to print with as all the scans I have ever had anything to do with were professional drum scans done at 300 dpi. So, I noticed, in a quick look that if I simply go under "Image Size" and change the Pixel per Inch from 72 to, say, 150, that my pixel dimensions go from 2272x1704 to 4733x3550. Hey! Where did all those new pixels come from? I don't want that. I want 2272x1704@150 or 300 dpi. I want my original pixels. No more, no less. Further investigation has shown me that unchecking the "Resample Image" box will, when changing the 72 to 150, give me an image which has gone from 31.556x23.667 inches to 15.147x11.36 inches while retaining the 2272x1704 pixel count. A change to 300 dpi will afford me an image 7.573x5.68 inches with a 2272x1704 pixel count. Now I would normally assume that this is the best way to do it. But, Photoshop is Photoshop and everyone seems to continually find a better way. So, with no regards to how long your Pi is or big your pixels are... I will ask again. Will not an image print better at 150 or 300 ppi than at 72 ppi? If the answer is yes, then... Is this in fact the best way to change the ppi of an image? Or dpi if you are considering, as I do, each pixel to be a digital dot. r > A typical digi cam produces an image that is n > x m pixels, that's it. If you wish to believe the pixels are 25.4/72 mm > apart, you may, but I prefer to think of them as reaching parsecs across > the universe. It simply doesn't make any difference. > > How many prime numbers are there between 10 and 20? (Hint: 11, 13, 17, > 19) OK, so what is the average distance in Greek gallons between prime > numbers in this range? How many miles long is pi? How many kilometres? > > Arrgh. > > Brian Chandler > ---------------- > geo://Sano.Japan.Planet_3 > Jigsaw puzzles from Japan at: > http://imaginatorium.org/shop/ jerk! jeez. worse than me AND jan put together.
