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Resize Image For Print
#1
This is something I can not wrap my head around no matter how many different articles I read, so I am hoping that by posting here someone will give me steps that make sense. 

I have an image that is 2201 x 1240 x 72 ppi.  I want to take a portion of it and make it 8-1/2" x 11" x 300 ppi to put on the cover of a magazine in Scribus.  I achieved this in Photoshop CS2, but I can't for the life of me, get it to work in GIMP.  The image comes in huge and when scaled to the frame, reduces the ppi to way too low, or the image comes in too small, and still doesn't work when resized. 

Please, please, please walk me through the steps of making a selection, cropping, resizing, setting the print size and the ppi and making sure that when I bring the file into Scribus, the image will be exactly sized to an 8-1/2" x 11" frame and be 300 ppi.

I don't know why this is so hard for me.  I have more than one Scribus book, for artist and photographer, and I have read online tutorials and the help file about resizing, re-sampling and setting print size, yet I can't get it to work.  I have to go to bed because I am so stinking tired, but I will check back after Thanksgiving dinner tomorrow night to see if anyone has come up with a way to help my oh-so-thick self.

Thank you.
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#2
The first thing to understand is that an image only has pixels. The ppi value is just a dormant value stored in the image and is only used when calculating print size.

Your image is 2201 x 1240 pixels.
At 72ppi, the image will print 2201/72 x 1240/72 inches
=30.57 x 17.22 inches

At 300ppi, the image will print 2201/300 x 1240/300 inches
=7.34 x 4.13 inches

So the image is too small to print 11 x 8.5 at 300ppi. It will have to be scaled, which usually means adding some blur as pixels have to be created. You will need:
(11 x 300) x (8.5 x 300)
= 3300 x 2550 pixels
(considerably larger than your 2201 x 1240 image)

The other thing to consider is asprect ratio
You require 11/8.5 = 1.29
Your image is 2201/1240 = 1.78
So your image will have to cropped or stretched to fit.
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#3
Blighty covers the subject, really all you need to know.

More specifically:

As Blighty said you will be scaling up by some amount, so expect some degradation in the image.

When it comes to using the scale dialogue, set the ppi to 300 before setting the new image size. Otherwise you tend to go around in circles.

edit: A revamp of the video showing the Image -> Print Size dialog to check and exporting as a pdf in Scribus since that seems popular these days.

In Scribus, there will be borders and bleed areas, I will let you sort that out. As a note, you could let Scribus do the scaling for you.

In the demo, Exporting from Scribus as a pdf.  Gimp by default will always open any pdf at 100 ppi. It will be 300 ppi but in Gimp up-to-you to set that value in the open-pdf dialogue.

Gimp -> Scribus -> Gimp 4 minutes.

sorry video out-of-date and gone
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#4
I now understand fully what I have to do.  I was going round and round as Rich said.  I just did what I needed, following your capable instruction and that awesome video..and voila!  I have a lovely 300 x 300 ppi 8-1/2 x 11 image on my cover!!   Cool
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