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How do I go from 72 to 300 ppi?

Federica Monsone , Feb 21, 2007; 05:52 a.m.

Hi everyone, I am a beginner at PS and need to save some images at 300 ppi. They were shot as fine JPGs on a Canon 350D. When I open them in PS Elements 5 it says they are 72 ppi images. HOwever they need to be 300 ppi for printing purposes. HOw do I do this? Many thanks!


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Jerry Tabachuk , Feb 21, 2007; 05:58 a.m.

Image > Size > enter new dpi which is 300, make sure the resample box is unchecked.

Ronald Moravec , Feb 21, 2007; 06:03 a.m.

All are slightly different, but image resize. Go to the bottom of the box and change resolution to 300 from 72.

The picture will reduce by 3/4 size. You may need to up rez to get to necessary print size.

Now you know why you shot max file size always without compression.

Federica Monsone , Feb 21, 2007; 06:30 a.m.

Great! I've done it. Thank you both. I am still overwhelmed by PS despite we've been covering it for a few months in my photography evening classes. HOw long does it usually take before you can retouch photographs to make them look good? I'm not talking about PS wizardry - just cleaning up backgrounds, cutting and dropping stuff in and out, that kind of thing....

Ronaldo R , Feb 21, 2007; 07:34 a.m.

Do NOT change your PPI - it's utterly irrelevant. Only pixel values are important.

Marshall Goff , Feb 21, 2007; 09:30 a.m.

PPI values ARE important for printing. It's the ONLY place that they are important.

Ronald Moravec , Feb 21, 2007; 09:59 a.m.

How long it takes depend how good your memory is, how good your instruction is, and how much you practice. I learned more in 4 months retirement than 2 years working.

How long does it take to learn to play a piano? Same thing.

If you have CS2, I recommend Photoshop CS2 for Dummies to start.

Do the basics first and learn where all the controls and tools are. Then do brighness contrast adjustments, color balancing, levels, curvers, layers, masking tools and masking, layer masking. Do one step at a time and move on. Then go back and review.

Never work on the original file. Lesson # one. Open the camera file and first thing is "save as" and rename it such as img 235psd.psd. Psd is the file extension and I also use it as the end of the name so I can identify it easily from the otiginal. You can save in PSD format with layers and adjustment layers intact and open and close as much as you wish without loss unlike JPEG which has a loss each time. You can also reopen and click on on a layer and rework it.

Jerry Tabachuk , Feb 21, 2007; 10:32 a.m.

How long does it take to learn to play a piano? Same thing

to play a piano you have to have the "gift from God" same to be a photographer, but to manage the Photoshop, a little less :)

Edward Ingold , Feb 21, 2007; 10:37 a.m.

Size, resolution and the number of pixels are related as follows:

Pixels = Length (inches) x Resolution (ppi)

If you set any two variables, the third is fixed.

A digital image best described by the number of pixels on a side - 2000 x 3000 pixels for example, for a 6MP image. The same image can be represented by a low resolution (e.g., 72 ppi) and large size (as you observe in Elements) or high resolution (300 ppi) and a smaller size - about 7x10 inches. You can change the size or resolution without any loss if you use Photoshop/Image/Image Size and uncheck the "Resample" box.

You don't have to do anything if you "print to fit" - the printer will handle these calculations for you and maximize the print area. If you need a specific size, you need to set that size in Photoshop/Elements. If the resolution is then less than 300 ppi at that size, you need to check the "Resample" box and change the resolution at that size to 300 ppi. It usually doesn't hurt if the resolution is larger than 300 ppi, except for publication and some printing services.

Hashim A , Feb 21, 2007; 12:17 p.m.

when decreasing the dimensions of an image (without resampling), the pixel density increases.

when it gets to the point where you have something like 450 ppi or even more - how does the printer handle the extra pixels?

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