That's right Shel. Provided you have chosen "New Image Data" in PS, which makes the computer calculate new pixels to put in between the original pixels - that's called interpolating, meaning that each time you increase dpi, you'll get more pixels in the image. The computer will put in a gray pixel between a white and black on, so to speak.
This is best done in steps, otherwithe the computer has to invent a lot of pixels without much to start from. I usual go like this: 72 - 150 - 300 dpi or ppi. Some people says that this on not at all necassary for printing - because the PRINTER will do the interpolation while resizing the image up to the print size that you have ordered. I don't agree, 'cause you then will NOT have the option to sharpen or improving the image using USM, shadow/highligt etc. You can resize - without choosing New Image Date - and get NO real changes to the file. Sharpening works better, I believe, if you have a lot of pixels to work with: Take a look at: http://www.luminous-landscape.com/tutorials/understanding-series/understandi ng-usm.shtml Remember that dpi (or ppi) in fact has nothing to do with the image dimensions. Dpi (= ppi = Pixel Per Inch) is about how you SEE it - on a screen, on a print etc. What matters is the amount of pixels that the image is made of. Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -----Oprindelig meddelelse----- Fra: Sam Jost [mailto:[EMAIL PROTECTED] Sendt: 13. november 2004 08:36 Til: [EMAIL PROTECTED] Emne: Re: Reducing File Size with Photoshop If thats really so, I'd think the resize algorythms of modern software would do this to achieve good quality without me even knowing it. I read somewhere one should sharpen the image before resizing 'cause some information gets lost. Maybe it was in http://www.luminous-landscape.com/reviews/software/pk-sharpener.shtml but I am not sure. Sam ----- Original Message ----- From: "Shel Belinkoff" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 13, 2004 7:58 AM Subject: OT: Reducing File Size with Photoshop >I recently heard that the best way to reduce a large file to one that's > substantially smaller is by using a step-by-step process rather than just > making the reduction in one step. I've numerous 4000ppi scanned B&W film > images of about 40mb and I want to reduce it to 100ppi with a wide > dimension of 800-900 pixels. Does anyone know what the procedure is for > doing a step-by-step reduction? I tried it by going from 4000ppi to > 2000ppi to 1000ppi, etc., but the results were soft and mushy. Is there a > better way to reduce the size and rez of such files? > > Shel >
