Only can import/download at 72 DPI what happened

Since iPhoto displays the photos on a screen whose pixel resolution is about 72 ppm it changes the "perceived" resolution to 72. The number of pixels in each dimension are not affected.

As you've been told already resolution, i.e. dpi, only comes into play when you go to print a photo.

-at what dpi does your camera normally output ?

-i would guess that the number of pixels of each photo is not affected

See "The myth of dpi" ( and a few other topics around the dpi ) in the excellent "All about digital photos", at

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

It's not a problem. Did you read the link?

Short answer: the dpi is set when you decide what size you're printing at.

Long Answer: Dpi means nothing in the digital world of your computer. There are no "inches" to have "dots per..." Size is measured in pixels. That's the same on your camera. It doesn't take 10 x 8 or 6 x 4 shots. It takes shots measured in megapixels. For instance 4,000 x 3,000 is a 12 megapixel camera.

Using that example, that shot from that camera has 12 million pixels. So that's how many "Dots" there are. To decide the ratio of dots per inch, you now need to decide the "inches" part. And that's printing. Print at 10 x 8 and the dpi will be 4,000/10 or about 400 dpi. At 6 x 4 then it's 4,000/6 or 660 dpi. Work the other way: Print at 300 dpi and the resulting image will be about 13 inches on the longer side.

So, your photo as a fixed number of pixels. Changing the dimensions of the print will vary the dpi, changing the dpi will vary the dimensions of the print.

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

Regards

TD

Well lower dpi means bigger average when printing, but it has nothing to do with the sharpness of the image. Camera (or apps like Photoshop) can tag an image at a sort of theoretical dpi but it truly means nothing on your screen, only when printing.

Even at that, one time, the rule-of-thumb for printing was to aim for 300 dpi, but that makes no little sense now as printers and printing technology have improved. Honestly, I don't believe there is an ideal dpi, but really only set one on a shot by shot basis.

Or deal wth people smart enough to understand simple third grade math

actually many times in the past it has turned out that the 300 DPI requirement is correctly done and does refer to the math problem not the setting and any photos that meets the third grade math requirement - not a requirement that a meaningless EXIF setting be made

LN

If they can not do third grade math (divide dots by inches - which usually does not even include those nasty fractions but is working ony with whole numbers like 4&6 or 8&10 to make it simpler) then there is no hope for them

LN

The comments here all make sense except that I am working on a submission to an Art Show and all of the photos must be at 300dpi. Sounds like I will need to a way to fake the file properties.

You can use the demo version of Graphic Converter to set the dpi to 300.

Camera (or apps like Photoshop) can tag an image at a sort of theoretical dpi but it truly means nothing on your screen, only when printing.

I'm guessing that telling the judges they don't understand third grade math would not leave a favorable impression of the application.

Not helpful.