Which file type do you send for printing large prints?

I'm just wondering what everyone uses for large landscape prints? .JPG or .TIF? I've started printing pretty large (30x60") using a JPG file and it looks fantastic, but I'm just wondering if there's a noticeable difference in printing with .TIF files(16 bit) over .JPG (8 bit) to the human eye? Kind of expensive to experiment I guess, so I'm reaching out for experience in this area. I'm going to print an image 40x120" in the next month so I want the best possible quality, but my .TIF file not even sized for 40x120" yet is 1.06GB, so it's going to be hard to send that to the lab. Advice?

Jpg. Quality = LR 80 / PS 10

Ask the lab, if they don't care, well, some people see a difference, others don't...you be the judge. For large prints, a "big" thing to bear in mind is viewing distance, and so how much of a difference will minutiae make?

Having done some relatively scientific testing I could find no significantly measurable difference between a 8 bit Tiff file and a Q80(10) JPEG from LR. By significant I mean that no single pixel had a difference greater than 2 in any colour chanel. I now use Q80 JPEGs for all images sent out to a lab. I print direct from LR to my home printer.

Alan

This is all great stuff to know....I've also learned over the years that a little noise in the shadows doesn't show at all on a print. People stress about it sooooo much and then you print it and it looks great

If the pixel count is identical for JPG and TIFF, the number of bits in the file used for each pixel might (or might not) merely account only for less perceivable 'steps' in color gradations (thereby overcoming the sRGB vs. aRGB debate), meaning squat for 'quality' of most photos

An analogy to that is 'quality' seen in JPG at Quality=80 vs. JPG at Quality=60