Enlarging DPI

[zooman123]

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?

Thank you for helping out a lost soul!

[zooman123]

I found my answer! Thank you.

[mikelee33]

Greetings,

Your "predicament" is very common in the publishing world (of which I've been a part of). It is unfortunate the publisher isn't of more help and furnish you a guide as to how you can meet their print requirements (many printers do this). DPI is a difficult concept for many, even those in the printing business. In today's digital world it should actually be easier to adjust your images for proper sizing and meet DPI "requirements".

This post could unfortunately get a bit long-winded because of the nature of this topic, but I will try to summarize. What you need to be most aware of is that you can (and could) furnish any size images you want to the publisher and have your product printed, but it might not look as good as you hoped for. They will print the images at 300dpi, resizing them as needed. So your images could look smaller than expected, or larger (and of poorer quality). You, of course, want your printed images to look as expected and so should prepare you images to fit a predescribed size at 300 dpi.

Thinking of you images as a certain pixel width and height makes it much easier when resizing them for print. A photo that should fit a 2"x3" printed box, when printed at 300 dpi, needs to be 600x900 pixels in size - end of story. Do not look at what you printed and assume that because it "looks" fine, that when commercially printed it will look the same way. Embed your properly sized images (and fonts if necessary) in your pdf file and submit it to the printer. They should furnish you some kind of proof for you to review to make sure everything looks OK. Even if the proof is in B&W you should still be able to confirm that the images will be sharply detailed.

Again, think and work in pixels and this will all be much easier.