Effective PPI for large scale printing

Forum|Forum|1 year ago
February 5, 2025
4 replies
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Hi!
I am saving a file tfor printed, its quite big 6990mmx2980mm, so I have made the file 50%. I am now adding in images, and for one of them, instead of just saying something like Effective PPI: 300 it says Effective PPI: 131x129. What does this mean? Why is is not just a number?

Also - placing TIFs is just gonna make a monster file - can I add JPGs? If they have 300 effective ppi? Any other tips for this large scale printing?

Thanks!

Print

Correct answer jmlevy

Why is is not just a number?

If you see 2 numbers, it means that the image has not been scaled proportionnaly.

Brad @ Roaring Mouse

Community Expert

Large scale printing like this, say for a mural or a billboard, does NOT need the same level of image information. In fact, most mural companies I deal with only need 50-75 ppi at final print size, so if you are doing a file at half size, you can certainly get away with an image around 100ppi. In any case, this is a discussion you should have with your vendor.

I do pull-up banner displays a lot and even they don't need much more than 100-120ppi.

TIFF vs JPG. Stay with TIF. You don't want to induce compression artifacts by trying to make them smaller by saving as JPG. Regardless, You should be linking the files, not embedding. It's when you save out your final print PDF for them you can control the file size and compression. That being said, because it's so large, you don't want to compress your images too much as the artifacts will be huge and very noticebale.

Robert at ID-Tasker

Legend

Also - placing TIFs is just gonna make a monster file - can I add JPGs? If they have 300 effective ppi? Any other tips for this large scale printing?

By @mikaelabirath

Depends on which file you mean?

INDD file - your document - only previews are stored inside - so size of the LINKED files doesn't matter too much - unless you'll link 1000s of very big files.

Exported PDF file - it depends on what export setting you set.

M

mikaelabirathAuthor

Participating Frequently

If I place 8 large TIF files, is this not goint to affect the file size of the final PDF?
Or can I place JPGs just as well?

James Gifford—NitroPress

Legend

Export to PDF almost invariably involves optimizing all image files to a specific resolution, typically 300ppi. The size of the source files don't matter much after that point, whether it's a 25MB TIFF or a 2MB JPEG. But yes, a large file exported with 300ppi/dpi images is going to make a very large PDF. There's not really any way around that except to optimize your export resolution to what the printer/output device can actually use; for most large format/grand format, it's not useful to go to regular print resolution since it will be viewed from some distance. Sometimes 100ppi is plenty. You'll need to consult with your printer or experiment with your output system to see what resolution is really needed for the results you expect.