Busy with end of semester and so I half followed a discussion about a certain substrate that someone didn't know the name of or whatnot? It's been a while. I don't know if the following information is any help to the original query for a name of the substrate or not.
So I wanted to add my two cents for a substrate I find really fun. It is called Sintra. If you go to the link, below, you will see 3 installations of the Parking Lot project on my website--the first is Bantex banner material, the middle is Sintra, and the right side are the original gum prints matted and framed (I know I know--funerary black frames--but had to do so because black frames were required by a couple of the galleries). These are three different show installations, not in the same space.
Sintra is like a hard plastic/composite sign board stuff, less than 1/4" thick. a 30x40" is about $115 here in Montana, and if you compute framing and matting that size, much less expensive.
It requires 100ppi at final size, so file size is not too huge.
If you make a gum print small enough to fit on a flatbed scanner, which I did for this entire project as I was intending to do the Sintra and banners, you can easily scan for this substrate.
It certainly isn't archival but it is sure fun!! It's for outside signs so it is quite UV resistant and durable, though.
It can be drilled with unobtrusive holes and easily hung and shipped.
I like my original gum prints best usually, but for some projects (e.g.this one where I want to have a feeling of being surrounded by 121st c. pop art trash) I prefer it! The Sintra fits thematically with a fast food culture project.
I wasn't going to mention it on the list here until some students had a discussion with me last week or so that they loved the small gum prints scanned and printed huge because it accentuated the grain and irregularities--the artist hand.
As far as the Bantex banner material, even though that is lightweight and soo so portable (you can roll up a whole project and ship in a tube) it reflects light and doesn't look as nicely crisp as a Sintra print. Bantex is like the stuff you see advertising Buy Your Coke in a Kmart.
Honestly, if I had the money I would use the diasec process, but one diasec of about this size is $400 so way out of my league. And caveat--I can imagine not all galleries would be into this kind of material--too populist and low-falutin'.
I'm not making a value judgment on small vs. big or archival vs. plastic, but just sharing thinking outside the box. For instance, Gregg, wouldn't it be great to scan your pinhole images and print this way??
Christina Z. Anderson