Help! DPI is Killing Me

[whitecrow]

I am trying to prepare some photos for a contest. The requirements are to submit on a CD with each image cropped to 8 x 10 and 300DPI.

Am I wrong or does DPI have nothing to do with the image until you are ready to print it. I don't even have a choice for DPI on any of my software (Photoshop Elements and ACDSee). I can adjust PPI, but that is it.

Any help would be appreciated.

[JamesB]

this thread mingt help you out

http://www.texasphotoforum.com/forum...hlight=300+dpi

James

[JamesB]

try looking at the aspect ratio chart as well

http://www.dpcprints.com/help.php?faq_id=61

James

[jazzdiver]

I only quickly glanced at those links, so maybe they do say this, but a short answer to your question Carl, is that someone is quoting DPI when they actually mean PPI. Too often those two terms are used interchangeably when - as the links say - DPI is a printer resolution but PPI is an image/scanner resolution. An image of 300ppi resolution, regardless of the print dimensions, is generally said to be photo quality when printed on a high quality printer. So, for example, a 2x3 inch photo would need to be 600x900 pixels in size to provide a 300ppi resolution. A 8x10" print would be 2400x3000 pixels. And so on. If your camera doesn't produce an image of that size, you'll need to resize it using the Photoshop Elements Image Size dialog, with resampling enabled so you can define the resolution at 300 ppi.

Regards,

Daryl

[maggot]

Actually, DPI and PPI have nothing to do with image resolution. If a digital image needs to be in an 8 x 10 ratio, then turn off resampling, and set the PPI to whatever is needed.

http://www.rideau-info.com/photos/mythdpi.html

[suzyjazz]

A way you can verify that you have enough pixels for the result they want is like Clarence said, to turn off resampling and set the ppi to 300. Your print dimensions will adjust accordingly to show you the size you can now print at with the number of pixels that exist in your image. If your result is less than 8"x10", I doubt you would be disqualified but you'd have to check the rules. They probably just want it cropped to 8x10 proportion. The resulting print dimensions are just a way to verify the quality of the image. Or, do the opposite. Set the print dimensions to 8x10 and see what the resulting ppi is. It's just an indicator of the quality print you will see.

A digital image is just a set of pixels. I think ppi (or dpi used interchangeably, incorrect or not) is useful when used in conjunction with print size (inches). I think in terms of print size and not in pixels, and this helps me see what the pixel density would be when the image is printed. Just be careful, if you increase the dpi with resampling on, you are actually interpolating the image (upsizing it). The computer is creating new pixels to make your image larger, based on the pixels that exist. On the flipside if you make it smaller, you would be tossing pixels you don't need which for me is desirable when making small prints (4x6).

[whitecrow]

Good info all, but I can't "set" anything to any DPI. As I mentioned, there is no DPI adjustment on any software. I think I got the point, however. Thanks.

[suzyjazz]

Oy, I am one of those d/pi offenders! I meant ppi. I am glad that at least one of the replies in this thread helped you.

[CaptainTom]

I have had some long and hard arguments with old time print media people who insist on 300 dpi and don't get it when I explain that dpi is something only the printer can control.

Most of them are still referring to dpi because in the past they digitized their images via a flatbed scanner.

Just be resolved that if you can control the ppi of your image via software, you can make them very happy in the end.