There is a range of ordinary inkjet papers with thin coatings from companies like Felix Schoeller, Mitsubishi, etc that certainly create color photo quality prints. The gloss with dye inks, the matte for both types of ink. The papers you baked in the sun had thicker, more complex coatings than used in the ordinary qualities and the last may stand the treatment better, at least on the coating bond.
Thanks. I had a look at those websites. Unfortunately, it seems that these are commercial-grade papers designed for large-volume printing, not fine art papers. They're certainly not cotton rag, and I doubt they are OBA-free either - if they were, the manufacturers would probably advertise them as such. They may not even be alpha-cellulose or acid-free. Without further information, certainly not something I'd be printing archival works on.
Blacks on uncoated papers like Arches with the inks you mention is visibly lower than on coated papers. The Dmax measurements show that too. On Biotop 3 the best measurement shows a 1.5 D, L 20.70, Paul hits at approx L 18.0 ( 1.6 D?) with Eboni on uncoated Arches, Photorag with HP Vivera can get to 1.82 D. It is not just that but bleeding of detail, mottle in gradations etc that count for me. I do not use QTR but an ordinary driver and can not boost the blacks though I doubt that would gain much either given the bleeding. For Platinum/Palladium prints I see Dmax values reported from 1.3 to 1.8.
I've seen 1.7 using Cone inks and a printer with a makeshift platen heater set at 55 degrees. No doubt many matte papers can exceed this. But a lot of other matte papers - particularly the heavily-textured ones - only reach around 1.6.
Where did you see a platinum print with a Dmax of 1.8? It's generally around 1.4, although it can be pushed up a bit more (to around 1.5-1.55) using multiple passes. At least that's out of the ones I've seen.
The surface of the prints made on uncoated paper can be handled far rougher than coated inkjet papers allow. Offset on opposite pages in books is no issue either. A big plus. So yes, what Mark tried to achieve with Hawk Mountain etc could solve other issues too. There is a thing we should not forget though, with pigment inks the gain in Dmax and gamut is by keeping the pigment layer at the top which inevitably leads to a delicate surface.
That's with dye inks. Pigments, in the cross-sectional micrographs I've seen, all stay on, or very close to the surface. I thought the loss of Dmax and gamut was due to the need to restrict ink load due to dot gain and drying times - accelerating the drying process allows for a greater ink load.
No doubt the surface would be more delicate than with a dye print. But delicate is OK - as long as the surface (and the image) doesn't start disintegrating even without abrasion, just through expansion and contraction of the substrate and minimal flexion.
What Aardenburg-Imaging showed as lasting; HM + Canson paper qualities + Z3100 and Z3200 Vivera pigments and more and more used with protective sprays. That does not cover the mechanical issues like abrasion and coating bond. Something I was well aware off but have no answer on right now other than framing behind glass.
The coating-on-paper papers, with no extra layer in between the coating and the paper, seemed to hold up very well -at least when uninked. Unfortunately, inkjet coatings are well known for developing micro-cracks when heavily inked... Still, something like BC Pura Velvet or Pura Smooth seems like it would be a good compromise - great lightfastness, good gamut and physically durable as far as coated papers are concerned.
The Kernewek line of canvas (by Kernow, tested on Aardenburg) look interesting. It's uncoated, unprimed cotton or poly-cotton canvas that's basically been soaked in inkjet receptive coating (so no coating to crack or flake off), has a better gamut and Dmax than most canvas and has very good print permanence too. Unfortunately, it's not paper...
You mentioned that your print results on uncoated paper were somewhere between newspaper and magazine output. I assume you mean in terms of gamut and dot-gain, not in terms of the dot pattern (which tends to be horribly low-resolution in both newsprint and cheap magazines)? Would you say the output is somewhat similar to that of a watercolour painting?