[gcaster51]

I have a Canon G2 digital camera, when I view the pictures and right click on them and go to properties the horizontal resolution is 180 and the vertical resolution is 180. When I do the same with the pictures my daughter takes the resolution is 300 in the x and y. Her camera is a 7 meg. Nikon (not a dslr) mine is just a 4 megapixel. I first notice the dpi of my pictures with the G2 when I was reading a magazine that was holding a digital photo contest that wanted pictures with 300 dpi. Is it the way the camera compresses the picture when it is taken? I have mine set to the highest resolution and the lowest compression. Don't understand.

[erick295]

DPI is just a number that determines how large the image is going to print. Some cameras default to 300, others default to other numbers, like 72. The resolution (pixel size) is what you want to look for when determining how much information is in a photo. With a 7MP camera, it's going to be high enough - they'll change the DPI to whatever it needs to be if they decide to print it.

[cwwozniak]

I found a review of the Canon Powershot G2 and it lists the maximim resolution as 2272 x 1704 pixels. The DPI only comes into play when you are trying to make prints of the picture files.

At 180 DPI, a 2272 x 1704 pixel picture would measure 12.62 inches by 9.46 inches when printed.

That exact same picture file printed at 300 DPI would measure 7.57 inches by 5.68 inches Unless the magazine is going to be publishing the photos larger than 7.57 x 5.68 inches, using a high quality printing process, your 2272 x 1704 picture files should be OK

[erick295]

Sorry, I missed that yours was 4MP. It will still be okay.

[slipe]

For the magazine to want a DPI they should specify a print or document size. As has already been pointed out, DPI is meaningless without a size.

DPI isn’t commonly used for pixel resolution anymore. PPI means pixels per inch where DPI means dots per inch. Since inkjet printers use a lot of dots to make a pixel, graphics people use PPI so it doesn’t get confused with printer DPI. Since the magazine specified DPI the person who posted the requirement might not know a lot about graphics.

If you change the resolution to 300 make sure that “Resample” is unchecked so the actual pixels aren’t affected.

[gcaster51]

Thanks everyone. I thought it was odd the magazine wanted DPI.

[thecoalman]

Originally Posted by gcaster51

Thanks everyone. I thought it was odd the magazine wanted DPI.

Send them a 300x200 300DPI image....

This is one of of my pet peeves, it's confusing enough without magazines and newspapers throwing in the DPI requirement. The local newspaper here has the same disclaimer... no "web quality" 72 DPI images. As I mentioned in another thread Professional Canon Digital SLR's default to 72 DPI... At the very least they should have a recomended pixel dimension if anything.... of course that will just lead people to resizing small images to the larger dimension. No easy answer but if someone is going to be requesting images and giving out specifications they should have a brief explanantion for people that are not familiar with it. I think it's throwback to a few years ago when they were probably getting a lot of scanned images where setting the DPI higher is important.

[cwwozniak]

Interesting set of articles on the relationship between SPI, PPI, DPI, and LPI and how they relate to printing digital photos in newpapers to high quality glossy magazines:


http://desktoppub.about.com/cs/inter...easure_spi.htm

[erick295]

Originally Posted by thecoalman

The local newspaper here has the same disclaimer... no "web quality" 72 DPI images.

People are evidently still under the (incorrect) impression that Web sites are 72dpi, even though they're not even printed. That comes from the fact that Macs use 72dpi to calculate font sizes. Even professionals swear by this - it's amazing how much incorrect information is out there. No wonder newcomers are so confused

[thecoalman]

Originally Posted by erick295

People are evidently still under the (incorrect) impression that Web sites are 72dpi, even though they're not even printed. That comes from the fact that Macs use 72dpi to calculate font sizes. Even professionals swear by this - it's amazing how much incorrect information is out there. No wonder newcomers are so confused

Just for the record most web images and image editors use 72 dpi for web images, and just for the record it really makes no difference since a web browser displays the image at the pixel size or whatever size the author has specified in the code. there was a similar thread about this and put up identical 100dpi image and 600dpi image to show there was no difference. Just for the heck of it I hit the print preview button and it was ignored there as well.

DPI is really irrelevant unless your setting the scale for printing or selecting it for scanning.