ziggy

what's the differece between dpi or ppi ,thx

MsOz

Whether or not it is going to be printed.
Try a web search for in-depth details.

Welles

Hi Ziggy,

Basically DPI (Dots Per Inch) is used in Printing. PPI (Pixels Per Inch) is used for screen resolution. They are often interchangeable if you are printing from your screen to an ink jet printer. If you do professional printing you suddenly must be more precise and consider LPI. Here's one of the best descriptions (with history) of DPI, PPI, LPI which was written by one of the old time regulars on the Adobe Photoshop for Mac who owned one of the oldest service bureaus in Florida. Long ago he gave me permission to share it with others.

ziggy

thx

melissa

Welles, can you tell me why when I go into a picture into photoshop and then to image size why the reading is ppi 72? I know that this just simply can not be true. I shoot with a canon 20D on the highest setting....... I do do a lot of down sizing to place photos on the web, but, does photoshop read the last adjustment setting? Or is it reading the actual picture?

Also, if it is reading the actual picture what am I doing wrong with my settings in my camera!!! I am at a complete loss! I can not believe that my photos have such a low ppi. Also, does that mean that I can not print them in large sizes???? HELLLLLPPPPP!!!

THanks!!!!
Melissa

fotobill

A friend who uses a Canon said his camera produces 72 dpi, you can change it in Photoshop to whatever you need

My Nikon produces 300 dpi and the Oylmpus I had before it gives 144 dpi.

melissa

Why is this camera only recording it at 72 dpi? How can you get a good print from that? How do you go into photoshop and change that? Do you have to do it BEFORE you send it to print? Or does the printer do this for you?

Melissa

melissa

Welles your link is not connecting to this question. Can you send me a new link to that discription. I really dont understand dpi vs. ppi and then printing. If you want to blow images up really large how do you do that. Shouldn't the printer figure this stuff out?? Or do I have to figure it out and then send it to them?

Welles

Melissa,

When you open a picture in Photoshop it is reading exactly what your camera has captured. I believe it may be valuable to think in terms of pixel sizes rather than dpi or ppi. If your image is 2400 x 3000 pixels you have enough data to print an 8" X 10" at 300dpi. If you wished to put that image on this forum, for example, you would have to downsize the image to 600px x 750px to meet our size limitations.

There is nothing wrong with your camera settings, I suspect, it's just that Canon seems to have chosen to have their image formats at 72dpi, which happens to be a sort of Mac standard.

The PDF on LPI, DPI explained has disappeared with the move to the new forum so I'll repost it. Perhaps it is a bit technical but will help you grasp the issue of pixels/dpi/ppi/lpi. It seems complicated but with a little experience you'll find it isn't a big mystery. You may conclude as I have just to think in pixels.

Welles

Aha. We're posting at the same time!

About printing. I'm assuming that you are referring to printing on your own ink jet printer? If your camera is saving it's files at 72 dip when you open the file in Photoshop, if you print at that resolution you will get a crummy print. For a good quality print, I use a standard print resolution of 300 dpi. So when you open an image in Photoshop, use Image > Image Size... Note the pixel dimensions. If you wish to print, change the Resolution from 72 to 300 in Document Size. Re-enter the original Pixel Dimentsions. Now the physical size in Document Size is what you can print at a high quality. If you need a bigger size your are going to be uprezing the image and Photoshop can do a good job, choosing Bicubic Smoother perhaps.