Questions About DPI

Cindyt

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I'm publishing via Createspace and understand they advise a 300 DPI--

First Cover: 286 DPI

1. Will a 14 dpi discrepancy make that much of a difference in the quality?
2. If so, how can I change the DPI? I do not have photoshop or any other software.
3. Would someone be kind enough to do it for me?

Second Cover: Way too small, like 66. something.

If I were able to up the DPI to 300 would that stretch the pixels too far?
 

tiggs

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I'm publishing via Createspace and understand they advise a 300 DPI--

First Cover: 286 DPI

1. Will a 14 dpi discrepancy make that much of a difference in the quality?
2. If so, how can I change the DPI? I do not have photoshop or any other software.
3. Would someone be kind enough to do it for me?

Second Cover: Way too small, like 66. something.

If I were able to up the DPI to 300 would that stretch the pixels too far?

So, here's the thing:

DPI is just an number stored in your image file that tells the printer the number of dots it should use to print your image, per inch. The more dots there are per inch, the higher the quality. The important bit to remember is: if you change the DPI in an image file, the physical pixels in that image file don't change, at all.

So -- if you've created the images with the number of pixels they've asked you to -- then you can just adjust the DPI using an online tool, like: https://convert.town/image-dpi -- and everything will be fine and dandy.

If, however, you've created the images at the number of inches they've told you to, and messed up the DPI -- then you'll need to resize the physical image to the right number of pixels, before you can change the DPI.

That's because the image needs to fit on a fixed-size physical book. For every inch it is across, you're going to need 300 pixels to fill that inch -- as that's what 300 DPI is.

If that's the case, then the 286 DPI image will need to stretch about 5%, because (300/286)*100=104.89%. It's relatively small enough that you may get away with it.

66 DPI, on the other hand, will need to stretch to (300/66) * 100 = 454.54%, which is a big nope.
 

Cindyt

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So, here's the thing:

DPI is just an number stored in your image file that tells the printer the number of dots it should use to print your image, per inch. The more dots there are per inch, the higher the quality. The important bit to remember is: if you change the DPI in an image file, the physical pixels in that image file don't change, at all.

So -- if you've created the images with the number of pixels they've asked you to -- then you can just adjust the DPI using an online tool, like: https://convert.town/image-dpi -- and everything will be fine and dandy.

If, however, you've created the images at the number of inches they've told you to, and messed up the DPI -- then you'll need to resize the physical image to the right number of pixels, before you can change the DPI.

That's because the image needs to fit on a fixed-size physical book. For every inch it is across, you're going to need 300 pixels to fill that inch -- as that's what 300 DPI is.

If that's the case, then the 286 DPI image will need to stretch about 5%, because (300/286)*100=104.89%. It's relatively small enough that you may get away with it.

66 DPI, on the other hand, will need to stretch to (300/66) * 100 = 454.54%, which is a big nope.


So I converted the dpi of my cover images and interior illustrations to 400 dpi, just to be sure, using convert.town. The change showed on my WORKS picture files, but Createspace didn't recognize the conversion. I sent convert.town an email. And they got right back with me. They've spent the better part of this week investigating the problem. Just got a reply. The image I sent showed 400 dpi on Paint (they sent a screen shot). The image conversion is true. He advised me to convert one to 1000 an see what happens.