VolkerSchulz
I recently bought some rolls of CHM 400 film. These are advertised as being identical to Kentmere 400, amongst others, and as having the same development times.
However, according to the packaging, the times are by no means identical. Development time for CHM 400 in D76 1+1 is 21 minutes, Kentmere 400 in D76 1+1: 14 mins (400 ASA). That is anything but identical. With other developers, such as Rodinal or Xtol, the differences are similarly significant.
Has anyone here in the forum had any specific experience with this film?
Best regards,
Volker
Morte
Yes, me. I use it as a replacement for the Kentmere and haven’t had any problems with it (mostly with A49).
In my experience, people tend to be far too slavishly fixated on pre-set development times, whether on packaging, online, in forums, etc. Film is forgiving, and everyone has their own methods, preferences, experiences, and so on! Hence my suggestion:
If you have two times that are as far apart as described above, take the average and see if you like the contrast! Then adjust the time up or down. Film development is not, and never has been, an exact science. Real experts (i.e. those who don’t measure in labs, but who have been developing artistic films professionally for years) will confirm this. Ask three of these experts, and you’ll get three different answers. And all three lead to good results!
VolkerSchulz
Since you’re using film, which exposure times do you use? The ones on the CHM package insert, or the ones from Kentmere?
Morte
I’ve no idea what it says on the packet. I’ve worked out my own development times. I’ve developed plenty of Kentmere films for 7 minutes 20 seconds in A49 stock solution. But it always depends on the lighting conditions when taking the shot – whether I wanted to increase the contrast or perhaps reduce it. At some point, I started giving Kentmere 400 a 320 or even 200 ISO exposure; I now do this with all 400 films because it allows me to achieve better differentiation in the lower tonal ranges. It simply looks better. But that’s my way of working! It might not be right for you.
VolkerSchulz
As I’ve been using Kentmere for quite some time now, I already know how to develop it. However, I’m interested in the development times for the CHM400 Universal. Since the development times are stated as being around 50% longer than for Kentmere, I’m starting to wonder whether it’s really just Kentmere in different packaging. Of course, I could test the CHM400 myself, but I’d rather not go to that trouble.
But it seems you don’t have any specific experience with the CHM400 either.
VolkerSchulz
I’ve now developed the film on the off chance, following the instructions for Kentmere 400. The Kentmere instructions specify 16–30 minutes for D76 1+1. This also applies to the CHM 400.
The development times of 21 minutes for D76 1+1 stated on the CHM 400 package insert are far too long and are likely to produce completely unsatisfactory results.
Morte
That’s exactly my experience. I developed the CHS400 from Fotoimpex in exactly the same way as the Kentmere and couldn’t see any difference.
Unsatisfactory results? I don’t think so. Just a bit more contrast.
grommi
21 minutes versus 16.30 is just 27% longer. That’s not really a big deal.
?
By now, one must assume that all Kentmere 400 derivatives are identical, including the RPX 400. With this, I recently achieved identical results to those with the APX 400n developed in the same tank. Hopefully, this puts an end to the back-and-forth, even if it’s a great shame about the original quality of the RPX 400.
?
I don’t know what the current situation is with the 100s, but I’m quite happy with the APX100n. With the 400s, I’ll probably have to dig deeper into my pockets again to get a decent film. In my opinion, the Kentmere 400 and the others are quite resistant to pushing.
Florek
Hi Volker,
Could you please post a screenshot of the times shown on the packaging? That might help us understand where the times are coming from. Perhaps they’re a copy-and-paste error from CHM 100 or something similar.
Best regards,
Florian
VolkerSchulz
Here are some photos of the film box.
€
Best regards,
Volker
VolkerSchulz
Here are some photos of the film box.
€
Best regards,
Volker
Florek
Here are some photos of the film box.
?
Best regards,
Volker
Good evening Volker,
Thanks for the photos!
It looks to me as though the dilution instructions for D-76 on the CHM 400 packaging are incorrect. In my opinion, the general difference for the other developers is due to the different speeds of ISO 400/27° in the Kentmere datasheet and ISO 320/26° for the CHM 400. Perhaps Mirko from Fotoimpex can shed some light on this for us?
Best regards,
Florian
Morte
The processing time for Rodinal 1+50 also seems rather long to me. However, this ties in with the frequently cited view that manufacturers’ recommended times can be seen as a bit of a push, based purely on laboratory measurements rather than an assessment of the image quality. That’s why I’ve so far successfully reduced almost all the times given in the processing charts by around 20% to achieve well-balanced negatives. But as always, this is a matter of taste and also depends on the enlarger.
