How large does a render have to be for large scale printing?

[michaelordway]

I recently printed a 48" x 24" image for a client at 150ppi. The size of the image was 7200x3600. The quality was beautiful, no problems. He's now requested it to be blown up even larger. He wants a 16 foot by 8 foot image (4.8m x 2.4m).

 

I don't think re-rendering at 28800x14400 is the best way of doing this. What sizes and what ppi can I get away with while still preserving image quality?

 

The image is going to go in a store window, so it has to remain fairly high quality from a few feet away.

 

Michael

[M V]

This has been discussed quite a bit on these forums. Almost beaten to death really. Try a quick forum search. The thing to consider is that the viewing distance on a billboard will be much greater than someone standing 2 feet from a printed board. If you climb up to one of those highway signs, you would see that its very low dpi. I think I have heard 18-30 dpi for billboards, so your render at 7200 should be fine.

[michaelordway]

You are absolutely right. I did a search in the main search window on the site's homepage, not on the forum search!

 

Thanks for the answer though!

[Stephen Thomas]

As a side note, those 3d people aren't going to look too pretty at billboard size. Might be worth thinking about replacing with photoreal people?

[Dimitris Tolios]

It is all down to viewing distance. My 27" 1440p screen is only 114ppi, but viewing it @ 24" (60cm) or more looks immaculate.

 

The natural viewing distance to fit the whole frame in our field of view is roughly the diagonal of the image.

That would be nearly 18’ (17’-10" 5.43m) or for your 16’ x 8’.

 

At this range, I think your current resolution will do ok...if they are to see it really close, I would perhaps double it...but don't try to get insanely precise.

 

I don’t know what kind of bleeding the 8’ wide capable printer will have also, how smooth the material will be etc…having a 150ppi source file for an output that cannot exceed – say – 100 true dpi, is a waste.

[michaelordway]

The viewing distance is usually the diagonal. That's a good measure to keep in mind. Thanks for all the advice.

 

I'm going to try printing at that size using the existing file as a test first. If it's good then I'll use that.