changing dpi

Question

Level 1

12 points

changing dpi

hello!
it is possible, once you have your photo in iphoto, to change the amount of dpi? i have some photo's that are 72 dpi but i need to send the photo's somewhere and they need to be 300 dpi - can I change this or does it all begin back when I took the photo? (i have version 6)

any help would be much appreciated

lucie

e mac Mac OS X (10.3.9)

Posted on May 9, 2007 2:22 AM

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Answer 1

lucielocket Author

Level 1

12 points

May 9, 2007 9:49 AM in response to PhillyPhan

what a pain!

thank you for all of your replies and help, I have decided after fiddling around ALL day I'm just going to send them what I have and let them change it!

kind regards

lucie

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Answer 2

May 9, 2007 4:43 AM in response to lucielocket

Changing 72 to 300 dpi would only make the file dimensions 4 times smaller.
That would make a 4X6 print size about the same size as a postage stamp.
Probably not what you want.
You set the dimensions at dpi on the camera before you shoot the picture. Changing it later is folly.

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Answer 3

PhillyPhan

Level 5

5,440 points

May 9, 2007 4:50 AM in response to QuickTimeKirk

I'm not at my Mac right now so I might be lying. However, I believe that iPhoto always imports at 72 dpi (and increases the dimensions as required). I don't think that he has 72 dpi for a 4X6. Depending on the camera's pixel count, it could be somewhere around 40X27.

If he's printing from iPhoto, he can ignore this entire issue as iPhoto and the print driver will take care of it for him.

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Answer 4

JMEH

Level 4

2,482 points

May 9, 2007 6:44 AM in response to lucielocket

Hi there,

There is software that will allow you to "change" DPI on image files. For example, Graphic Converter or Photoshop Elements. It's a slightly complex process but to go from 72 to 300 is not normally done...

Also, I would try to open your image in Preview if at all possible, and then select "Tools" > "Get Info", this should show you the actual resolution and DPI of your image out of the your camera. DPI is directly related to resolution (pixel dimensions H x W). DPI depends on the final print size v. your original resolution & DPI and most digital cameras will use @ 180 DPI. For example, if you're camera is shooting 5 megapixels at 150 DPI, making an 8 x 10 print should result in at least 300 dpi when printed... make sense?

Good luck, Rick

iMac G5 iSight 20" - 30G iPOD in Slimming Black - WD 500G FW - Mac OS X (10.4.8) - HP Pav 15" WS and Toshiba Sat 17" WS LP's - Canon 20D & A620 Kodak P880

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Answer 5

May 9, 2007 7:06 AM in response to lucielocket

What is the output size that they/you are printing to.

The first step in getting the image to a certain dpi is to make sure that the pixel dimensions are such that the values for height and width are at least 300 times the desired output height and width in inches.

To get a 4"x6" print, the file should be 1200x1800.
To get a 8"x10" print, the file should be 2400x3000.

The image can be scaled up or down to arrive at the correct pixel dimension, but going up (the original file is too small) will tend to make everything bigger/blockier.

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Answer 6

lucielocket Author

Level 1

12 points

May 9, 2007 7:26 AM in response to Mike-N-nahyunil

hello again,

thank you for all of your replies

Maybe I need to explain myself a little clearer! i'm not going to be printing out any photo's, they are to be emailed/or put on a disk so that they can go onto a website (i'm a textile designer)...they (the website people) have asked for images as JPEGS at 300 dpi or more with a suggested size of width 640 x 512 height.

I actually have two problems, one is it that some I have taken some photos myself, and when I view them on preview they are 72 dpi and jpegs, whereas I also have some more professional photos taken by a photographer, and they are 300 dpi - perfect - but saved as tiffs - if only they were all the same!

I did speak to the website people and they said it could be done, but I'm thinking that's because they have photoshop, and unfortunately i don't, so anymore thoughts?

lucie

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Answer 7

May 9, 2007 7:34 AM in response to lucielocket

Thing is, dpi really doesn't matter unless the file is destined to be printed-the images will show on screen at the dpi of the monitor-which varies from monitor to monitor.

If they need pics at 640x512, send them pics at 640x512.

If you want to change the dpi setting, it can be done in photo editors like Photoshop Elements, and probably some less expensive one's like GraphicConverter that you can find on http://www.versiontracker.com

As for the tifs, taken by the pro, in iPhoto, go to File>Export and change the format to JPG.

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Answer 8

lucielocket Author

Level 1

12 points

May 9, 2007 7:43 AM in response to Mike-N-nahyunil

So the pro's photos i can do,

but one last thing...i'm sorry...i'm so bad at this! how do I send them 640 x 512, i've tried the iphoto file-export thing and if you change the width, it changes the height automatically you cannot specify the height...am i missing something?

lucie

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Answer 9

May 9, 2007 8:23 AM in response to lucielocket

It's preserving the aspect ratio so that the image doesn't get stretched or squashed.

If you want to get the 1.25:1 ratio of 640x512, you'll need to crop the image. In the edit window, set a Custom constrain and use the crop tool to select the area of the image that you want to keep.

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Answer 10

PhillyPhan

Level 5

5,440 points

May 9, 2007 9:11 AM in response to lucielocket

I went through the same thing with a photo contest. The sponsor stupidly required a 300 dpi minimum. Their web site absolutely refused to accept my 72 dpi shot despite the fact the total pixel count was roughly nine million and the 72dpi was based on a print size somewhere around 30X50! I used PhotoShop Elements to "change" the file to 600 dpi for a 4X6 and all was OK even though the total pixel count remained the same.

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Answer 11

lucielocket Author

Level 1

12 points

Mar 26, 2009 5:52 AM in response to lucielocket

having had the same problem again, I have now been able to use your solutions and solve my problem...so a big thanks to all who replied

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