Here's a group of my friends painting up in Vermont
Although I am a traditional painter I don't limit my choices to only historic materials, as you saw in my post on pigments for instance, when I replaced the old Alizirin with Quinacridone red. When modern methods work, I use them. I have been experimenting with a new canvas from Fredrix called Red Lion. It is a relatively new product made from a material called polyflax. This is a completely synthetic canvas. It doesn't come and go at all. Since it is synthetic it is not hydrophilic, that is, it doesn't absorb water from the air and "grow". I expect it is probably as archival as you can get, as it won't rot. This canvas is absolutely consistent in texture which is nice, no slubs, no knots, no larger or smaller lines in the weave, perfect. Incidentally a slub is an annoying little lump in the weave often where the line or thread has run out and a new one is knotted in. That's why fancy linens say they are picked and pumiced. Essentially they are gone over by hand and have these lumps sanded out.
Although it is acrylic primed I have been enjoying painting on it. It is a little too absorbent and toothy and I may try putting a primer coat of white oil paint of my own on it before use. Once I have the painting laid in of course that problem goes away. I have only been using Red Lion for a couple of months but I haven' had any problems with it yet. It certainly stretches up well. It is very inexpensive and has a medium texture. I like the slightly pronounced weave and flawless look under my paint. The stuff seems to be tough as iron and I have been impressed with its resistance to damage when I scrape a passage out with a palette knife. The last painting that I posted that I titled the Mountains of Maine was painted on this canvas. Red Lion canvas is available from most of the online art supply outfits at a very reasonable price.