Rumor has it that the currently available Adox CHS Art 25 is the same emulsion as the now discontinued Afgapan APX 25. I still have some old stock of APX 25 in 120 roll film format. Unfortunately this film was never produced in sheet format. So, I bought a roll of the Adox material and decided to carry out a little experiment. The currently available Efke PL25 emulsion also appears very similar to the APX material, and it is available in sheet format in both 4x5 and 8x10. The quality control of the PL25 material is not the best as I often get negatives with coating flaws and emulsion issues. Despite this, it is one of my favorite films and I use is on a very regular basis. The newly available Adox material is hopefully very similar and perhaps of a little better quality. It too is available in sheet format... Onward with the experiment. I loaded two film backs for my Hasselblad camera, one with Adox CHS and one with APX 25. Then over the course of the last few months, whenever I was shooting medium format, I would take two identical shots, one on each film. I recently finished shooting these two rolls and set about processing them. I always loved the smooth tonality of APX 25 developed in Rodinal 1:50. So, back home in my darkroom I loaded the two films onto reels and put them in a developing tank. They were processed together with Rodinal developer, diluted 1:50, for my standard time. I am not convinced that the new emulsion is identical to Agfa. It is certainly very similar. The Adox negatives look a little brighter and have a bit more contrast. I suspect that this is at least partially because the Adox film was fresh, while my old APX stock expired seven years ago. The base fog is noticeably a little higher in the old film. The conclusion is that the emulsion is at the very least, quite similar. It appears as though development time may have to be reduced slightly to produce a negative of the same contrast. I've attached scans of a number of the images from these rolls.
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