On Jan 4, 2006, at 10:10 PM, LuAnn Johnson wrote: > > I edited some pictures with iPhoto, and sharpenening them just a > little made them look clearer on the monitor. I then put 8-10 on > one 8.5x11 page in Appleworks drawing and printed them at Wal-mart > for a friend to use in scrapbooking. The results are horrible - > everything is splotchy and grainy - the way it looks when I over- > sharpen. > > I printed them again on my home HP printer, and they are just as bad. > > The pictures look perfect on my monitor, so I don't know why this > is happening. Could it be because I shouldn't have adjusted the > sharpening? > > When I've done slideshows on iMovie, I have always sharpened the > photos just a bit, and they look much better. The pictures that > look great in iMovie look horrible when printed. > > Any advice or suggestions? > > Thanks. > > Luann >
Hello Luann, Well, it's been a very long time since I've discussed this, but I'll attempt it (albeit setting myself back a at least a decade) because my photo- application of choice is Photoshop 3 ? now years old. However, the basics should still be the same. As I see your described problem, it's just the understanding of a key piece of the photographic/print process that you need. <: Resolution :> If you can, check the resolution of your photograph. If you are starting with a traditional photo, it is probably a continuous tone, and I'll assume you've scanned it in. Check the scanning software settings for resolution reference. Traditional photographs are continuous tone from lighter to darker shades, have used some sort of screen in the bulk printing process to break up the image so the printing presses and printers can print a facsimile of the photograph. Modern digital cameras refer to pixels, megapixels, etc., which is roughly similar to resolution, but much finer. Many photographs found on/for computers have a 72 dpi resolution, by default. High quality photos may (should) have a much higher res. References: -- "D.P.I." (dots per inch) -- "L.P.I." (lines per inch) -- "P.P.I." (pixels per inch) Monitors have two kinds of resolution. There are differences, but commonly, monitors have a (device) pixel density of 72 ppi. This is different from the choices offered under the 'Displays' prefs (software), which only changes what you see on screen, not the device pixels themselves. Printers print at certain resolutions, and may offer several different choices of available screens in different *patterns*, and possibly dpi/lpi density to choose from when applying to a photo to print. When you see a printer resolution reference of 300 dpi, 600 dpi, 1200 dpi, etc., that's the general resolution for print output. For decent quality output for any unaltered photo, you should have a minimum of 300 dpi; 150 dpi is course, but can work. If you are altering a photo and plan to publish by printing, your picture should probably have a minimum 600 dpi resolution. Internally, your photo may be a 72 dpi (course resolution), and when sharpened, it will have essentially made the pixels *more* course from pixel to pixel. When you view these pics on similar monitors/devices, they look fine. Printing, however, will amplify these differences, not improve them. If you are going to publish to CD or Web, monitors will display your images fine, but if you are going to publish by printing, *start* with a relatively high resolution picture (300 to 600 dpi). If I haven't been too terribly wordy, I hope this helps. Regards, Russ Preston | The next meeting of the Louisville Computer Society will | be January 24 at Pitt Academy, 6010 Preston Highway. | The LCS Web page is <http://www.kymac.org>. | List posting address: <mailto:macgroup at erdos.math.louisville.edu> | List Web page: <http://erdos.math.louisville.edu/macgroup>
