No, actually image degradation is probably more an issue for a plastic based material than a fiber base one for number of reasons. For one thing, microfilm is the standard in archives for longterm records retention and preservation reformatting. Fiber based papers are used to make archival prints for some types of projects like a building survey or whatever reason, but microfilm is what other materials are compared against. If it's done to the standards--this includes type of film, process and storage--it's LE rated (life expectancy--they don't use the term archival) for 500 yrs. Polyester based films are very stable and don't require the lower temps that the acetate films have. My guess is a fiber base paper would be maybe 100 yrs or less, but it would depend heavily on how it was stored. Paper isn't going to be as stable as a polyester support because of temp & rh and handling. Same goes for an RC paper. If the paper itself didn't self-destruct from say the dev-inc. agents, or the brighteners, or preservatives-- if it was stored in a climate controlled vault it could be considered "archival"--might be a hard concept for some to accept, but it comes down to the storage environment in the end. You can spend all sorts of money on archival processing & enclosures, but if the environment isn't right, it won't mean much in the long run.

All these materials are different because of base supports--but the thing in common is silver halide emulsions. Silver is silver. It might be that microfilm is finer grain, and has a tighter pattern for the emulsion, and is more sensitive--I don't know really, I'm a photographer--I'm not a conservator, an archivist or a materials engineer....But I do know that microfilm is the standard for archives. They have a whole set of ANSI/ISO standards that they check against. These include filming & storage--from enclosures & handling to temp & relative humidity. We follow similar stds. where I work for storage of objects--to keep our AAM accredidation, and I can tell you that the criteria would be almost impossible to do outside of a temp controlled facility or vault. It's really hard to do even in a facility designed for this purpose...you pretty much have to put things away forever, or view them for short periods of time without committing the unforgiveable act of touching them, and use uncomfortable temps & rh's and lighting.

So what you have is a bunch of archives around the country that discover problems with their microfilm collections over a span of a decade or so. They study it, and come with these recommendations--which include a change in the way the film is toned & post-treated. They also begin to review the standards for storage...but this also includes regular film & photogaphic images in general. You won't find many studies out there of photos in the "real world". There are no set standards being followed for the most part. Alot of funding for institutions is contingent on these accredidations and being able to follow these standards. It's what defines a professional institution. But what this means is pretty much putting images away in dark rooms, or in cold vaults away from anyone ever seeing them--and displaying copies or using "surrogates". The prints are treated as artifacts or master images with duplicates used. It's just different...they're looked at as records, not so much art. Outside--people process film to their own made up standards, they display & handle them however they see fit. Nobody can predict how long anything will last, not even a manufacturer, without some control to go against. You couldn't find a bigger test pool than microfilm in archives....

There's a theory that rc paper is more sensitive to pollutants than fiber because the emulsion is lying on top of the support. the base traps pollutants and they can attack the image from both sides. With fiber , the theory goes, it allows pollutants to pass through and the damage is slower. So, it could be a big deal--depends on what you're doing I guess. Where I work, we're film based for longterm, so it's of interest to me and I pretty much believe it's all the same in the end...