Topic: Tetenal Ultrafin developing times

[Nigel]

I looked at Tetenal Ultrafin as a possible, cheaper, alternative to my usual HC-110. Your comments on that would be appreciated on that subject, although that's not the point of the post. I was hoping for some help deciphering these development times!

I've looked a quite a few developer datasheets in the last 40+ years (f**k!) of developing film, but I have no clue what they're getting at here.

Say I want to develop Tri-X at a 1+10 dilution, what the hell are the A and B about? Do I go for 5 minutes or 9 minutes? It mentions "Beta = 0.55" at the top, 9 mins x 0.55 = 4.95 mins, so we could call that 5 mins. But what that means I have no idea?

Also, the A=3 sec, B=1 min at the bottom, what's that all about? Do they mean invert for 3 secs? That seems too short! 

[Francois]

Looks like they calculate the time in number of inversions...
Never seen that before.

Maybe you should just rely on the massive dev chart instead.

[Nigel]

The massive dev chart says 9 min, so that makes sense. But it would be good to know what this means.

[Kai-san]

The A=3 sec and B=1 min is labeled inversion agitation rhythm. One way of reading the table is that the A column requires inversion every 3 seconds while the B column requires agitation every minute. That would mean that A is continuous agitation, which could explain the difference in developing times. But I'm a bit skeptical that continuous agitation should halve the developing time.

[Nigel]

I'm pleased it wasn't just me being thicker than usual. I think it's safe to say it's not as clear as it could be!

[Kai-san]

I found a post on Photo.net that confirms my theory. Otherwise very little to be found on this developer.

[Francois]

Well... they definitely outdid themselves on that one.
Thing is that since the 1+10 is on top of the A B, it looks a bit like if it's A+B... and the times don't say that they're times.

Oh well... not surprising when you know it's German (not a bad thing for our German members, it's just not instantly obvious). They did invent DIN sensitivity ratings where adding degrees multiplied things because everything was on a logarithmic scale (https://en.wikipedia.org/wiki/Film_speed#DIN).