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LegMaker
4th of December 2003 (Thu), 20:33
Is there a "best value" of DPI to save dig photos at when you want to print them? I've been saving them at 300 DPI. Is that enough? Can you save them at too great of DPI? I've heard that it can degrade the picture. Is this true?
Thanks all.

GenEOS
4th of December 2003 (Thu), 21:07
I save all of mine, 5"X7" at 200 dpi, but I keep the RAW files as a master, untouched.

With this file, I can even print an 8x10 without any problems.

ldivinag
4th of December 2003 (Thu), 22:01
i would save them as the same res as your printer can handle...

robertwgross
5th of December 2003 (Fri), 00:38
No, you can't save a file in "too high" of a resolution. On the other hand, that does take up space on the disk. I keep my good images stored at the maximum resolution that they ever were, probably 18MB or 36MB for a 6MP image.

Besides, you never know when you will have to take a small crop out of the 18MB image and try to print that to larger print size.

If you downsampled the file to match to some printer that you have today, then sure enough next year there will be some breakthrough printer technology that looks even better when you use a finer file.

---Bob Gross---

hmhm
5th of December 2003 (Fri), 08:46
I think there may be some confusion over terminology here.

I "save" my images in whatever native resolution they already had.

When it comes time to print them, I upsample or downsample as needed for the size of print I'm planning to make. I typically have to upsample for 8x10 or larger, and downsample for 4x6. I never save this image, its just temporary for printing.

When you print an image that isn't at the "native" resolution of your printer, the print driver will either upsample or downsample as appropriate. I prefer to do this in Photoshop, as I _suspect_ (though don't know) that it will do a better job than the print driver will.

It does seem like it should be reasonably important to get this number right. If you upsample to 600 dpi and the printer downsamples back to 300 dpi, I'd have to assume that all this unnecessary translation causes some image degradation.

All that said, it doesn't seem like printer manufacturers like to tell you what their real resolution is. The inkjet guys like to tell you stuff like "2880 x 1440" because those numbers sound bigger, but that's not a real-world dpi figure.

All that said, I use a Canon S900 and generally resample to 330 dpi in Photoshop before printing. I'd love to know what the "correct" thing is, though.
-harry

CanonUser
5th of December 2003 (Fri), 12:18
There are 2 resolutions to configure when you work with digital image. You set the PPI (Pixels Per Inch) resolution upon creating a new document. The printer converts each of those pixel to DPI (Dots Per Inch) according to the print quality and media that you choose from the printer's properties screen.
Generally, any PPI resolution between 180PPI to 300PPI will work. Most of the articles I read recommend 200-250 PPI as the correct setting to send to printer. You don't have to resample the PPI for different print size. The actual pixel size will scale up or down with the print size. People tend to view 4X6 at a closer distance than 8X10 or 11X14. So, if you set a document to print 225PPI at 8X10 size, the pixel will shrink if you print the image at 4X6 or it will increase if you print at 11X14 size. The pixel change in size will not be apparent to the viewer due to the increase or decrease viewing distance. If you get up close to one of the road side advertising billboard, you'll see that the smooth picture is actually comprised of baseball size dots. Of course, you can resample the image, that's your other choice.
I normally save the RAW files as is on CD, convert them to 300PPI TIFFs when needed, do the retouching on this "master" image, save a copy of this "master" image for flattening/resizing/cropping, print this copy, then either delete or save the copy depend on the need.

Hope this helps,