Adjusting dev. times with rotation

[coops]

Is there a need to adjust the developing times when using a tube for 4x5 and constantly rolling in water as opposed to using a tank and inverting every minute? I am using HP5 and D76 1:1

Thanks

[Leigh]

The purpose of agitation (inversion or rotation) is to bring fresh developer in contact with the emulsion.

Using continuous agitation shouldn't make a large difference unless you're using a very fast-acting developer.

I suggest looking at the Jobo documentation for their recommendations.

- Leigh

[Lenny Eiger]

Is there a need to adjust the developing times when using a tube for 4x5 and constantly rolling in water as opposed to using a tank and inverting every minute? I am using HP5 and D76 1:1

Thanks

Do a quick test for N with whichever system is your new one and come up with new times. No one can answer this for you.... Manufacturer's times are only a guide, and usually will not produce useful results. Development times are based upon a certain look, which may or may not be the one you're after.

I don't know what you are trying to accomplish, but unless you are contact printing, I'm not a fan of either that film or that developer. But hey, that's just opinion...

Best of luck,

Lenny

[Lachlan 717]

Try reducing the N ('Normal") time by around 15% with continuous agitation.

[joselsgil]

Is there a need to adjust the developing times when using a tube for 4x5 and constantly rolling in water as opposed to using a tank and inverting every minute? I am using HP5 and D76 1:1

Thanks

coops, are you using BTZS tubes or? If you are using BTZS tubes, I would think that they provide you with a guideline to go by.

Another way to test the development times. Try exposing film to a 18% gray card,(or the Northern sky without clouds). Make sure you used the same exposure meter that you will be using in the future. Develop the sheets in either 1 minute or 30 second intervals. 1st sheet at say 5min @20 degrees, 2nd sheet @ 5 1/2 min., 3rd @ 6 min., you get the general idea. Make sure that the developer is the same for all of the tests. This should give you an idea as to what time to use as a guideline. This can also show you if you are getting even development, too much agitation, or other development problems. It is time consuming, but its better than always hoping to get a decent developed neg.

Once you get your times down, remember stick to them unless you change film or developer.

Good luck and let me know what you come up with, as I might be tempted to try it myself.

[philbed]

There is a big difference between Jobo tank and BTZS tube : size. I use BTZS tube since 2002. I have done a lot of tests. Here is a links to calculate new time for a developer film combo (http://www.phototec.eu/infomag_erechner.php).
To my experience, I have the best result for N development with G 0,55 time.
Hope it helps.

[coops]

Thanks for the responses. I decided to do my onn testing, seems its the only way to know for sure.

[John Kasaian]

I just reduce the "normal" times by 15%.