Massive query concerning render resolutions vs real world print measurements.

[Legmog]

Hi peeps

I'm a 3D artist, but to my discredit I (as of yet) have never really taken the time to examine the relationship between the pixel resolution I render my images at, and how that translates to real world print dimensions.

I rarely do work for print, and am always at a loss when (on the rare occasion) a client says ''I need a 'X inches width' by 'X inches height' image! My brain (which only knows pixels) just gets confused as all hell, thinking ''Ok how does that translate to pixels!!'

The 3D software I use is 'Cinema 4D'.
In C4D's render settings you CAN change the numeric values from pixels to real world measurements.
I'm currently working on a project which requires a 3D rendered image to be printed off at 6 meters width by 2.77 meters height.

Now then...

Inputting 6m x 2.77m (at 150 dpi) and seeing what that is in pixels....
That's a whopping 35583x16427 pixels!!!
To my mind, that seems to be an absolute overkill ridiculousness... There's not even enough intricate detail in the image to warrant anywhere near that level of resolution. When I zoomed out to view the entire canvas space, I was viewing it at a scale of 4%! When viewing the image at 100% magnification, I swear I'd need a computer monitor the size of an office block to view the entire canvas.

I attempted to render this image at that resolution. After 15 hours, C4D crashed at about 60% of the way done. So my question...

WHAT IS the relationship between pixels and real world print measurements? How does it work? I'm sure I must be able to render at a far more practical pixel resolution? 35k x 16k pixels is crazy! And for my computer... Technically impossible.

For 6m x 2.77m, what should the pixel resolution be?

Thankyou VERY much in advance!

 

[Paul Murray]

Generally, for print you've going to be looking at up close, for example images in a book or photographs on a wall, you'd use a standard resolution of 300dpi. For larger images that will be viewed from a distance, such as a billboard, or banner for an exhibition, you could go down as low as 15 dpi because nobody will be looking at it close enough to spot the low quality. There's a few print experts on here who can advise, but uUltimitely, I'd ask the client to check with whoever is printing the file for the resolution they'd want the final file supplied in. They should be able to tell you for sure.

 

[Levi]

Ok, I do 3D design too and basically you're doing the rendering side of things wrong.

What you should be doing is talking to the client/printer etc about the dpi/bleeds etc they use for the work being produced/printed, as said by Paul the standard dpi for a book is 300dpi but it's only going to be about 20 inches at most in most cases so you'd do a render that is 300dpi multiplied by height/width and use those as your render resolutions, which in this case is like 6000 pixels at most. Obviously this would change if you're doing a banner and be 15dpi x height/width.

So for your 6m x 2.77m image you would first need to know the dpi and then it would 6m (convert to inches) x dpi and 2.77m (convert to inches) x dpi for your resolution. I'd personally also zoom out a little and go slightly larger than needed to allow for any bleeds that may be required on printing.

IF on the very rare occasion you need high dpi and large size (I'm assuming C4D has this feature) you can do split renders where you render multiple 'sections' of the whole scene rather than trying to do the whole thing in one go and then stitch it together in photoshop or the likes.

EDIT: I changed the 3rd paragraph for clarity, after re-reading it I realised I missed out an important element.