I looked into this several years ago and came across this article from a conservator at the National Gallery of Canada:

Mounting large format photographs: a temporary and reversible alternative to dry mounting

“The final product provides an even weight and tension distribution for the artwork in a way that is safe, aesthetically appropriate, and 100% reversible.”

I used to work at a lab and would shudder at the total cost of scanning, printing and framing/mounting sometimes. Instead of traditional framing you can have prints mounted to different types of board. Like dibond, aluminum or acrylic, face mounting or gator board, for example. A bit more modern looking since you don’t have a mat board and a frame. Is usually hung using aluminum tubing mounted to the back of the board and hung that way.

Back in the day when photographers printed their own prints, many would have a print dryer, which featured a slightly curved polished metal sheet with a canvas cover. Once the print was dry, you could also use this to mount your photos using sheets of some sort of hot glue between the print and the backing. Here is a pic of one: https://williamsdesign.ca/?product=heatrite-photographic-print-dryer the one I used was pretty big - you could get a lot of prints done in one go… probably about a meter across and a bit longer maybe 1.2m.

Much the same way that smaller photos are, just on a larger scale with heavier duty materials that are exponentially more expensive as they still have to be pH neutral and reversible so as not to damage the print.

Any works on paper should always be hinged from the top between a mount and undermount, essentially an acid-free barrier in front and behind the artwork/photo. Any tape should be acid-free and reversible too. Here’s a good example pic to illustrate.

Like I said, the main difference is the size/cost. A regular sheet of mountboard costs me around £6 for a 44" x 32" sheet. Meanwhile a 104" x 60" 4-ply cotton museum board costs me about £133. That’s literally just the cost price of a single sheet of mountboard, before you’ve even considered the rest of the frame, glass etc or the labour costs.

How big are we talking here? 20x24 I’d still mount with a backing board, hinged front mat, and corners. Though I’d flatten it in a dry mount press first. I’ve never needed to deal with an actual print that’s bigger.

The reason I ask is because I am thinking of making some large prints, like 40x60 or larger, but am not sure what to do once I get them.

I think this explains the popularity of ready to hang art like metal prints which don’t need a frame. Metal is surprisingly robust and although pricy, aren’t as pricy as having a paper print framed. If it was smaller, I’d frame it myself but a 40x60 isn’t something I’d attempt.

It depends on the purpose to the display of the photos.

A friend, now an award winning photographer, goes to various events to show off his photography, with a focus on his 2 big projects. He makes 18x24, 2x3 & 4x6 prints of his subjects.

He has long strips of aluminum or plastic, that get clamped to the top and bottom of the prints. Those then become the hanging points and weight to hold the print straight.

Really big nails that they have to put in with a really big hammer, wielded by a really big person who eats really big portions of soup of really big carrots.

A museum wouldn’t face mount an unmounted photo, but it won’t stop them from acquiring a photo that was face mounted by the photographer. Contemporary photographer may have their prints mounted in DiBond. Which will keep them flat and have a nice look. Causes a few headaches with handling and storage, but museums deal with it if that is what the photographer wanted.

I just strongly advise make sure the framer is using actual brand named DiBond. If seen knock offs delaminate which creates a whole new set of nightmares.

My first real-job was in a graphic arts repro shop, pre-digital. We often mounted very large pieces, like blowups of crime evidence for trials or installation work, up to maybe 4’ x 6’. At the time they used a big vacuum press, and they also had a large heat press for dry mounting. This wasn’t for museums and archival work of valuable stuff, for the most part.

The photo labs I used in the film era used large dry mount presses; the Seal Magnapress was 4’ x 8’, it used heat and vacuum for the pressure. D&K still sells a press of about 4’ x 6’, it’s like 12 grand. With a 20x24 dry mount press, you can do fairly large pieces if you plan them right - the top of the press has very wide, offset hinges so the work can be moved around under the hot part. I have an 11x14 dry mount press and I can mount 20x24 with it. Most of the lab work was done on acid free foam board with claimed-to-be archival mounting tissue.

“Supposedly”, high-quality dry mount tissue is removable, I’d guess you re-heat it and remove it when it’s softened, but no idea if then you have adhesive residue to remove? Never tried it.

While people talk about hinge-mounting with a mat as being the most archival and only “acceptable” way to mount fine art prints, many photographers preferred the perfect flatness of dry mounting, and galleries have been happy with it - the prints are usually better presented when dry mounted, unless you like the aesthetic look of ripples. I’ll hinge mount prints in deeper (almost shadowbox) frames without a mat and have curves and ripples - IMO, sometimes a print is a print, and sometimes it’s more of an “artifact”, a physical object that happens to be a photographic print. But shadowboxing is a more difficult and expensive way to frame, as you need the glass to be set in the frame, and then a sub-frame of some type to separate the art from the glass.

What’s really large? For me it’s billboard sized photographs

The Met in NYC just had a run of displaying Avedon’s murals. They had the one of Andy Warhol’s Factory crew and one of military/ political figures among 1 or 2 others. If you haven’t seen them, he shot groups of maybe 10 people using a large format (not sure 4x5 or 8x10) and made 3-5 frames side by side to show the whole panorama of people in each mural. Very cool stuff. The prints are maybe 8-10 feet tall, when combined in the mural each mural was maybe 20-30 feet long. Each individual print of the mural was just a free hanging print on the wall. No frame, glass, mounting, etc. I think they were just clamped at the top and hung from the ceiling or the wall. Really cool presentation.