BTZS developing times

[Mike M]

Hi Everyone,

I've recently started using BTZS tubes and would like to see some input on development times. I realize that dev. time is a function of the entire photographic process, but would like to read what people have to say about estimating times based on manufacturer's recommendations.

For example, I've recently switched my Kodak TXP / HC110 setup to BTZS tubes. Kodak only gives suggested times for tray & large tank processing. I couldn't figure out where to start with my dev. times compared to these methods as a starting point for film testing.

Any advice? I went with 6 1/2 minutes @ 68F rather than the recommended 5 min tray & 7 1/2 min large tank. Based this on the fact that there is less developer used than tray, but more continuous agitation than large tank. Seems to have worked okay but I haven't printed the negs yet.

If anybody has any say about where to start in comparison to manufacturer's times, I'm sure lots of us would like to hear them. Additionally, advice on speed of rotation of tubes would be appreciated.

Thanks,

Michael

[Gem Singer]

Hi Mike,

Developing film in tubes is similar to developing it in trays. Both methods are considered to be continuous agitation. You'll be in the ballpark if you reduce your regular slow intermittent tank development time by 15%. Since you mention that your tank time is 7.5 min., your tube development time is really close at 6.5 min.( both times are at 68 degreesF).

The amount of solution has no effect on the development time. I only effects the capacity of the developer ( the number of films it can develope before exausting). The dilution, the temperature, and the time are the deciding factors.

[Philippe Bedfert]

Mike,

As you say, time is a function of the developing process. It depends from the Subject Brightness Range, the paper you use, the constrast you which and many other parameters.
For instance for a "normal" development (SBR = 7, gamma = 0,5) I develop 4x5 FP4 sheet in HC 110 1+79 for 6:05 mn.