I'm creating an image collage for an A0 poster. I started making the image full size, 300dpi, but Photoshop won't save it because the file is too large.
I assume my best bet will be to scale down the image to 50% or so, but will this give me problems later on when passing artwork on to the printer? I have vague memories of making display banners at 25% final size in my first job but that was a long time ago...I'd ask the printer, but a supplier hasn't been selected for this job yet.
I just called a poster printer to see if they'd give me advice and my hunch was correct: so long as the image is 300dpi I could supply it to them at A3 size and they'd be happy to print it up to A0. Phew!
Scaling A3 up to A0 at 300dpi would give you roughly 105dpi at full size. This *should* be ok with A0, they're not gonna be standing less than a foot away from the poster, but something to keep in mind anyway :)