I am not sure if this is off topic, but I will have a go as I think it is relevant.
What is the closest modern age available film to APX 25? I have searched the archives on apug, and the discussions are all pretty old or bordering on argumentative. I am a relative newby to film, having only gotten serious in the last year or so. When APX 25 comes up it seems to get religious levels of passionate debate.
I have a nice supply of APX 100 thanks to Ultrafine Online and about 100 feet of APX 400 off a fellow APUGer. I have recently seen several eBay auctions pop up with old stock of APX25 and PanatomicX that has God knows what kind of storage history selling for extremely high cost (to me at least).
Now I have been able to stash about 300 feet of TechPan away in my freezer. So far my results have been pretty impressive using P. Formulary TD3 for souping. I also have about 50 rolls of rollei ATP 1.1 in 120 format stashed away. Tests with it have been good, but my scanner quality for anything other than 35mm is lacking, so really my 35mm and 120 scans wind up being pretty close in quality. At this point in my life a real darkroom and enlarger setup is just outside my means for space/storage.
I have developed some Imagelink HQ, HSU, and copex microfilms in 16mm and minox formats, but that seems to be the only size I can actually source. I do also have a couple rolls of CMS20 in 35mm in my bag waiting to be shot.
I guess ultimately i feel like I want to be able to say i have at least expeienced all or most of the iconic films of recent history. So, given all my existing low speed stock that seems to be in the same asa range, am I going to get some sort of experience to match what I might have seen with the real APX25? Or should I bite the auction bullet and risk it on some of the real thing? FWIW, I have considered some of the Rollei 25 and Efke 25 that is available at Freestyle or B&H.
I kind of look at it like being able to shoot Kodachrome before time ran out. I don't have any iconic favorite keeper slides. However, I did get to fire off 4 rolls of K25, and I feel like I did get a little glimpse of nostalgia/history because of that. And before someone reminds me to focus on mastering one particular emulsion before branching out, keep in mind that (at least partially for this instance) my motivation is not only to make great final images. I really am trying to get these emulsions while I still can find them on the market. I also don't feel as bad about stashing away the low ISO B&W films for years to come. My Tech Pan bulk rolls are many many years out of date and still have virtually no fog.