I have learned from experience that talkning about ppi (ppi = pixel pr. inch)) when scanning is really nonsence. A pixel doesn't really have a physical size* - it's a code in a computer. Ppi only makes sence in connection with a media for viewing. A 72 ppi image looks great on a computer screen, but poor on a print. This should be more like 300 ppi or more.
Note)* I know that a 35mm image (app. 1 inch) will get you either appr. 2000 or 4000 pixel on the short side - appr. 3000 or 6000 on the long side of the neg. if you scan "to original", meaning the original size of the subject in the scanner. I allways set the scanner to "to original" to make sure all the figures (parameters) don't confuse me. What really matters is the number of pixels in total!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Back to your question. 4000 ppi means 4 times more pixels in you image, than 2000 ppi (see the above decribed example). If there's not enough detail or info in your neg/slide/print, that you are scanneing, it won't help you to increase the number of pixels in your scan. In my experience (my scanner is not the worlds best) anything above appr. 2200 ppi is a waste of time and space. If you loose detail is annother question, since the grainstructure in the film will never exactly "match" that of the "grid" in your scanner. I guess you'll always "loose" a little somthing, grain structure, colour depth or whatever. I believe the "sound wall" for resolution for lenses/film is appr. 100 lpp/mm. For digital it's currently perhaps 6500 ppi. Not many scanners can do that well anyway. I guess what I'm saying is that when digital cameras/scanners convincingly reaches something like 7500x11250 pixel** (84 Mp) on a 24x35mm format digital will give the same or better resolution than the best 35mm film. But that's at 100 ASA at the most. On a tripod. And everything else at the best. So, perhaps the "35mm film sound-wall" is more like 30-50Mp. In the real world (200-400 ASA, handheld, consumer lenses) my negs don't give me much more than 2200 ppi (7Mp). BUT remember that film and digital are not and will never be the same or even compareable. It's two completely different things IMO. I you want to bring out all the qualities of a 35mm neg - have a chemical photograph made in the conventional way. Simple as that. Note )** Black-white-black: It takes three rows of pixels to make a linepair. 100 lpp/mm means 300 pixel pr/mm or 7500 ppi. Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -----Oprindelig meddelelse----- Fra: Shel Belinkoff [mailto:[EMAIL PROTECTED] Sendt: 2. januar 2005 22:07 Til: [email protected] Emne: Scanning Question Assuming that you're scanning at the same bit depth and with all other parameters the same, would there be any loss of detail or information or whatever when scanning at 2000ppi v 4000ppi? Shel
