There is also a closely related strategy known as "defensive patenting."
plus another strategy, I'm not sure if it has a real name, but it's along the lines of:
"let's not patent this thing, because as soon a we do it's in the public domain and competitors will try to get as close as they can without infringing the patent, instead let's just hope / presume it's so innovative that nobody else actually manages to figure out how to do it too"
And there's also the oft-mentioned problem that not everything is patentable, nor covered by one.
Certain things about the methods they used to test accelerated-aging may be patentable and patented, as would be the improvements in chemicals for the next film as a result of those tests.
Some things may have been (at the time) 'obvious to a skilled worker in the field' and not patentable (whether or not it would be obvious to someone skilled in the field today).
And other things just aren't patentable at all, like the results themselves. They'd probably just be stored in a filing cabinet someday until someone declares them a fire risk and throws the whole lot out (don't laugh, it happened at my old job with years of sales and design records).
