Indesign downsizing DPI of images

Forum|Forum|6 years ago
December 16, 2019
4 commentaire
1534 vue

Hi all,

Have you ever heard of InDesign downsizing the DPI of any images? Say you place a 300 dpi image and it downgrades to 270 dpi?

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Rob de Winter

Community Expert

Hey, just an extra explanation to make this a bit more clear without all the numbers 😛 , I created an image for you:

When you make an image larger in InDesign, the resolution will go down (like the image below). When you make it smaller, it'll place the pixels (or dots) closer to each other. The resolution will go up. So InDesign itself doesn't change the image DPI.

By the way, if you notice the resolution changes in your PDF, make sure your you don't downgrade the pixels in the PDF Export menu, in the compression section.

focusedm17724973Auteur

Participant

Thanks, everyone very helpful. To avoid this issue I did increase the size in photoshop and on some images created a bleed area to keep the integrity of the images, also ran a preflight and it came back with no issues.

But very good to know that the resolution can be affected like this.

John Mensinger

Community Expert

InDesign doesn't do it, you do. And, it's not a "downgrade". In fact it's mathematical proof that the image itself is unchanged.

The simple math: If you place an image that is, say, 5" x 5" @300ppi (not DPI), then increase its phyiscal dimensions on your page by 10% to 5.5" x 5.5", the effective resolution (that is, the output resolution of a 5" x 5" image scaled, without resampling, to 5.5" x 5.5") is affected inversely by that same factor of 10% and falls to 270ppi. The same holds true in the other direction too. If you reduce the physical dimensions of that same 5" x 5" image down 10% to 4.5" x 4.5" the effective resolution will increase 10% to 333.333ppi.

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datap6156868

Inspiring

Hey there, Yes the dpi will downgrade if you enlarge the image size in InDesign than its actual size.