View Full Version : camera resolution vrs print resolution ?


jeff
07-16-2002, 09:30 AM
My camera shoots pictures that when checked in Photoshop are 72ppi. My question is do I leave it that way all the way to printing or do I increase it to 300ppi? How do I get the best prints? Ofoto, which I use also wants my pics in RGB. Is it common for most digital cameras to take pics in 72ppi? Are there cams under a $1000 that take pics in lets say 300ppi. My photos are 1600x1200 normally and about a meg in size. Jeff Graves

gland
07-16-2002, 01:59 PM
Looks like your camera is about a 2-megapixel model Jeff. This will work for 4x6 or maybe even 5x7. Most cameras do take pictures at 72ppi. Mine, a 3.1-megapixel model, has a tiff mode that produces a 9 meg file. Can't take too many shots with a 64 meg CF card. :)


I've found that with my camera, (2160x1440), in super fine mode produces a file about 1.3 megs. This is actually a 30x20 at 72ppi. I reduce the size in Photoshop and can generally print a good quality 8x10 on my Epson 1270.

G. Couch
07-16-2002, 05:45 PM
Jeff - gland is correct. 1600x1200 will produce excellent 4"x5" prints (at 300 dpi) and very good 5"x7" (at about 228 dpi).

Most digital cameras still use 72 dpi as the default since up until recently digital pics were only intended for viewing on a computer monitor. To see what the size is at 300 dpi just go into Photoshop, go to image size and uncheck the "resample image" box. You can now type in whatever value you want for resolution or height and width and Photoshop will adjust the values accordingly. The important thing is that the number of pixels will not increase or decrease, just the printed size. Your 1600x1200 image could be printed at 8x10 (150 dpi) or 4x5 (300dpi). Either way, it's still 1600x1200 pixels. Getting the best prints depends largely on the capability of the printer, but 250-300 dpi should produce very sharp images.

john_opitz
07-16-2002, 08:29 PM
Check this out

about Print Res. (http://www.ledet.com/margulis/PP6_Chapter14.pdf)

Stephen M
07-17-2002, 09:37 AM
Some related links, including the one mentioned by John.

http://members.ozemail.com.au/~binaryfx/PSTV_links.html#R

Stephen Marsh.

Rachel
07-26-2002, 09:08 AM
I've always remembered this general rule of thumb when printing. First, take the resolution you are able to photograph in and then divide by 200 (optimal printing resolution) to see what the optimal printing size will be.

For example, if have a 1.2mp camera, it can take photos to a max size of 1024x768 pixels. Divide 1024 by 200 (resolution you will need to print at to get a decent print) and the optimal print size is 5.12 x 3.84 inches.

If you want a larger print, you will need to increase the res of the photo.

DJ Dubovsky
07-26-2002, 11:19 AM
They usually take pictures in 72 dpi but if you view them in Photoshop, open your rulers under View > Rulers and you will see that the picture is the size of a poster in inches. Remember when you lower the image size to what you would want to print, say 5x7 or 8x10 for example the resolution will increase. Just make sure the Resample Image box is unchecked in the image size diagram box.
DJ

Doug Nelson
07-27-2002, 05:01 AM
Great article on camera resolution in the current PEI magazine. I learned a lot. It should be on their website in a couple of months.