View Full Version : Render Resolution vs. Billboard print.

07-14-2005, 04:47 PM
Hey folks... have a lil question I thought someone would have run across before. Trying to figure out the render resolution that would upscale decently to billboard print size. This isn't a question about render dpi vs. print dpi. I've done this for many years ... but am trying to figure out with a client what we think appropriate pixel render size would accomodate blowups to billboard size, at a) a minimum render size, b) an optimal render size.

Someone over at one of the agencies tried to push the idea through of a 40inch by 50inch at 600dpi to accomodate a blow up to billboard. I nearly fell off my chair laughing as that is about a 2gig file just to accomodate pixel info. Never mind renderer's not being able to accomodoate that size (its.. 24000x30000 pixels), nevermind the renderer just looking at me and saying .. abort abort.

Anyway.. if anyone has any info, or experience with this.. please let me know.

Steve. ([email protected])

07-14-2005, 05:25 PM
billboards are generally 14' x 48'. this equates to 168" x 576".

there are 72 ppi in a render. this would mean that a billboard at 72 dpi would need to be 12,096 pixels x 41,472 pixels. of course we know this is not possible. generally billboards are printed (or used to be when they were offset) at about 3 or 4 dpi. extapolate (heh, i used a big word) that into a reasonable render size and you'll get something like (i used a higher number for a better resolution) 5040 x 17280 pixels at 30 dpi. this might be doable. i've done some stage backdrops at about this size and with the current printing technology (vutech) they came out very nice.

depending on your memory limits you might have to move the scale down from 30 dpi.

hope this helps.

07-14-2005, 05:51 PM
Seams like I read somewhere's that road side bill boards are printed at 12 dpi because they are so far from the road, giving the illusion of a higher dpi. If this is true then yes I would agree 30 dpi would be doable.
Maybe the thing to do is find out how far away the reader will be, for example in NYC billboards can be right next to the road, but then they usually are quite high off the ground. Perhaps the owner of the billboard could give you some specs to use.

07-14-2005, 06:08 PM
I was chatting tonight with a designer who does a lot of print work for Universal Music, and he was telling me that the rule of thumb he uses is that it's about [email protected] = 1foot at billboard print. The dpi for billboard print is anywhere from 20-30dpi depending on who's printing it and they interpolate up. City side billboards are generally 20feet x 10 feet, and larger on the freeways and larger roadways.

Sooo... that would make a 20x10 foot billboard render around 7200x3600 - 6000x3000 pixels depeneding on interpolation if my math is correct.



07-17-2005, 05:14 PM
Another option you may want to consider is rendering a high res image at a smaller size, printing it the final image from a very high quality photo-printer on a high-quality paper (if you don't have one a service bureau could do this for you pretty cheaply) and then having the final image professionally drum-scanned at the resolution and size you wish to have it printed at.

07-18-2005, 01:59 PM
Hi Steve !

I've done few PRINT size works and i was doing 6000*7000 renders in Lw 7.5 with only 1GB of RAM. Worked fine at end but lasted little longer than it should since it used another 1,5GB of VMem :). But i ha donly one object in scene and it wasn't more than 10k polygons. SO if you are planing to do car renders in subpatches don't even think of it under 2GB RAM machine and preferably 4GB RAM in machine :). Good luck ;).