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Old Dec 18, 2005, 9:10 PM   #1
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Okay, I have read the other posts & articles about 300 dpi, but am still left confused...I am using an Olympus C5050 Zoom digital camera.* I have taken images in the "Super High Quality" mode.* Looking at the image properties, I see that the photo is at 72 dpi and is 2560 x 1920.I am using Adobe Photoshop for my editing.* I am looking to enter a photo contest (magazine print) that requires the photo to be 300dpi at 8.5" x 11".When I'm in Photoshop, I do the following:1.* Open Image Size2.* Uncheck the "Resample Image" box.3.* Change the resolution from 72 to 300 pixels/inchWhen I do this, the document size then changes to 8.5" x 6.4" which is too small for the contest requirements.* Is there anything else I can do?* Or something that I need to do differently?* Or, do I need to do anything at all...is the 72 setting okay?Thanks for any advice you may have!Jennifer
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Old Dec 19, 2005, 1:14 PM   #2
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To get 8.5 X 11 at 300 PPI with that image you have to resample.

Your easiest approach in Photoshop is to select the crop tool. Put 8.5 and 11 inches in the width and height boxes and put 300 pixels/inch in the resolution box. Crop the image and you will have the image required.

Your proportions aren't exactly right for a 8.5 X 11, so you will require a little cropping in any case. It is easiest to just use the crop tool for everything.

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Old Dec 20, 2005, 6:25 PM   #3
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With your camera, there is no way to get 300ppi in an 8.5" x 11" size without resampling. If you open a new canvas in Photoshop with those dimensions, you will see that your pixel ratio will be 2250 x 3300. This works out to about ~8.4 megapixels minimum.

You can go through the steps that you outlined, but before accepting the changes, click on the "resample image" box and make your changes, then OK them. But as mentioned, you'll end up with some areas needing to be cropped. Since that's the case, the previous instructions will get you there. The crop box will show you what an 8.5x11 area represents in your image, and by selecting 300ppi, it will automatically resample the resolution to that size upon cropping it.
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Old Dec 29, 2005, 11:37 PM   #4
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dpi is ink per inches
ppi is pixels per inch

72ppi is approximently equal to 300dpi on a standard ink jet printer in terms of quality. Adding more pixels than 72ppi will not really improve picture quality at 300dpi. This is why people print at 600 or 1200 dpi to take advantage of a high resolution camera. 300dpi is a minimum for a decent picture. Your camera should be fine.

Here is a site that may help you clarify the difference between dpi and ppi

In other words, you camera should be fine.
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Old Jan 2, 2006, 10:55 PM   #5
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What Carskick said was basically accurate, but just to avoid any confusion, it's best to simply think of PPI and DPI as the same thing when dealing with your files. I submit full page ads to various magazines and if they want a file that is 8.5" x 11" at 300 dpi, that's what your exact image size should be in Photoshop. I don't need to know what dpi their printer is going to use, they know what they need.

The camera I use at work is about 6 megapixel and doesn't generate images that are that large, so I just resample the images to a larger size. How much enlarging I can get away with depends on the usage, but for a magazine I can typically enlarge up to around 150% and it comes out fine. You may need to apply a bit of unsharp mask though.

You might also want to find out if the photo is to be printed full page, and if so, how much bleed there is. You'll probably want to be sure nothing important gets cut off.
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