DPI Imaging and Printing

zooman123 · 01-12-2008, 10:19 AM

Intro: Hello. I'm self-publishing a book and I'm running into some serious photo editing problems. The customer service department of the printing company is horribly slow, so I'm turning to you for help :)

Problem: All of my images in the book (over 100) are saved at 72 DPI jpg. They are large files, so when I transfer them to Microsoft Word I desize them and they print out fine at home.

However, the printing company says my photos are all between 81 and 96 DPI (I have no idea where these numbers came from). The photos need to be 300 DPI for optimal printing.

Question: If I re-sample the images via photoshop to enlarge their DPI (and decrease their size), will this work? For example, the photos are currently 10x12 inches. If I resample the images to 300 dpi, they change to 2.4x3 inches (the perfect size).

From my research and logic, resampling would appear to work. But here's where I'm running into trouble. Previously, when I transfered the regular images (72 dpi) and shrank them down to 2.4x3 inches, it looked EXACTLY the same as the 300 dpi. Both images print fine for me at home. So why would the initial 72-dpi-image cause any trouble with the printing press if it comes off as a 300-dpi-image when shrunk down in Word?

Is there something going on I can't see? Is it a problem with Word?

How can I tell what the DPI is of images that are in Word document or in a Acrobat pdf file - like the printing company does?

**freddyhard** · 01-12-2008, 04:28 PM

resizing the image will only make it worse. whether you are enlarging or decreasing it and every time you do this it just gets more fuzzy.

when the printers say that it is 81 and 96dpi, that is only ½ the info. what is the image size in inches (or mm) it needs to be on the page?

so to work out an actual print size of an image, open the image with photoshop or even a lesser photo editing software and look at the size of the image in pixels. then divide the width and height by 300 and this will tell you the actual print size in inches. so if the image is 2400x1800 and being printed at 300dpi then the image size will be 8"x6". if it was being printed at 150dpi then it would be 16"x12".

zooman123 · 01-13-2008, 07:54 AM

Thank you! It's all good to go now.

01-12-2008, 10:19 AM	#1 (permalink)
zooman123 Registered User Join Date: Jan 2008 Posts: 2 OS: Vista	DPI Imaging and Printing Intro: Hello. I'm self-publishing a book and I'm running into some serious photo editing problems. The customer service department of the printing company is horribly slow, so I'm turning to you for help :) Problem: All of my images in the book (over 100) are saved at 72 DPI jpg. They are large files, so when I transfer them to Microsoft Word I desize them and they print out fine at home. However, the printing company says my photos are all between 81 and 96 DPI (I have no idea where these numbers came from). The photos need to be 300 DPI for optimal printing. Question: If I re-sample the images via photoshop to enlarge their DPI (and decrease their size), will this work? For example, the photos are currently 10x12 inches. If I resample the images to 300 dpi, they change to 2.4x3 inches (the perfect size). From my research and logic, resampling would appear to work. But here's where I'm running into trouble. Previously, when I transfered the regular images (72 dpi) and shrank them down to 2.4x3 inches, it looked EXACTLY the same as the 300 dpi. Both images print fine for me at home. So why would the initial 72-dpi-image cause any trouble with the printing press if it comes off as a 300-dpi-image when shrunk down in Word? Is there something going on I can't see? Is it a problem with Word? How can I tell what the DPI is of images that are in Word document or in a Acrobat pdf file - like the printing company does?

01-12-2008, 04:28 PM	#2 (permalink)
freddyhard Design Team Moderator Join Date: Apr 2005 Location: Éire Posts: 1,598 OS: 2k (still!)	Re: DPI Imaging and Printing resizing the image will only make it worse. whether you are enlarging or decreasing it and every time you do this it just gets more fuzzy. when the printers say that it is 81 and 96dpi, that is only ½ the info. what is the image size in inches (or mm) it needs to be on the page? so to work out an actual print size of an image, open the image with photoshop or even a lesser photo editing software and look at the size of the image in pixels. then divide the width and height by 300 and this will tell you the actual print size in inches. so if the image is 2400x1800 and being printed at 300dpi then the image size will be 8"x6". if it was being printed at 150dpi then it would be 16"x12". __________________ "It takes two to lie, one to lie and one to listen" Homer

01-13-2008, 07:54 AM	#3 (permalink)
zooman123 Registered User Join Date: Jan 2008 Posts: 2 OS: Vista	Re: DPI Imaging and Printing Thank you! It's all good to go now.