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November 2007
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2007.12.09 18:54 "Re: dpi settings", by Toby Thain
On 9-Dec-07, at 4:39 PM, Andrey Kiselev wrote: > On Sun, Dec 09, 2007 at 11:15:51AM -0600, Bob Friesenhahn wrote: >>> For me centimeter unit is quite inconvenient for the image >>> processing >>> related usage. I like mm. >> >> It seems that the best unit to use depends on what is being measured >> and the intent of the measurement. > > That is very true. And we are talking here about resolution tags which > intended to set up the relation between image pixels and actual > size of > paper sheet or display. And millimeters are quite convinent in > measuring > of paper sheets and displays. Centimetres also, see previous. Furthermore it does appear to be established convention in pre-press (my old métier). --Toby > >> For example, if the TIFF file represents a satellite image covering a >> large expanse of the earth, and it is desired to specify the actual >> resolution, units of millimeters would be inconvenient. Perhaps >> meters or kilometers would be more convenient. If an image is from a >> microscope, perhaps nanometers or micrometers would be more >> convienient. > > Oh, no, you are just mesunderstanding the resulution tags purpose. > They > have nothing to do with the actual image content. The same 300 dpi > image > can be the view of the whole Earth from space or just a bacteria > photograph, but it still remains the 300 dpi image. The scale of the > image content should be established via anther tags. > > Best regards, > Andrey > > -- > Andrey V. Kiselev > ICQ# 26871517 > _______________________________________________ > Tiff mailing list: Tiff@lists.maptools.org > http://lists.maptools.org/mailman/listinfo/tiff > http://www.remotesensing.org/libtiff/