Thanks.
I believe Clyde Butcher used to enlarge 12x20 negatives to mural size - does/did he use a graphic arts machine?
Re: diffraction: Indeed. I just started shooting 8x10, and am quickly learning about diffraction limits. I have only made contact prints and examined negs under my 8x loupe so far. From negs I have examined, my guess is that I would be good up until f/45 for 4x enlargement (32x40"). I have already found the need to close down to between f/64 and f/90 for many works, and yesterday had to make a close up abstraction within a Century Plant at f/128. Even then, I'm not sure whether this latest neg will hold universal sharpness. For these images, I just have to accept that they will only ever be 8x10 prints.
Nonetheless, I've long fantasized about one day making epic landscapes at a scale of presentation akin to the Hudson River School, for that level of visceral impact. Like those earlier works, I would also want the viewer to be able to then walk in and observe the tiniest details. To give the illusion of being able to walk into the work. It seems that that kind of fine detail holds until 4x. I'd want the print to be at least as tall as a moderately tall male person, and I find 1.66 to be a very agreeable aspect ratio in my motion picture work. So, let's say one orders the 20" film from Ilford, cuts it into 20x33 sheets and has some ridiculous camera system made (the lens would be another issue). The prints could theoretically be enlarged to 80 x132 (6'8 x 11'), but again, if we are limited to f/45 for 4x magnification, all landscapes would have to be distant with no mid-ground elements. Presumably it would be similar depth of field to shooting a landscape at f/11 on 8x10 - not a lot!
Anyway, are there existing graphic arts machines that could house such a large negative?
Failing that, can you even drum scan such a negative?
J