Agitation during development.
For developing tri-x, Kodak recommends 5-7 initial inversion cycles in 5 seconds, then 5-7 inversions every 30 seconds. That's what Kodak says for N development. At the darkroom I'm involved with, everyone seems to have their own style, but most agitate for 30 seconds initially, then 10 seconds every minute after that. It would seem this would give you different negatives than if following Kodaks recommendations. It's 2-3x more agitation that they recommend. Does it really matter how you agitate, so long as it's consistent?
Either method produces good negatives. If you are more comfortable with Kodak's instructions then by all means follow them.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
~Antoine de Saint-Exupery
The one thing I learn from following Apug is that consistency is king. Only if you are consistent can you fix problems reliably and quickly. So like Gerald says, either is good, and I've used both in the past.
PS: "different" does not equal "bad" especially in darkroom work. As long as you're consistent you can experiment with the difference between different differents and pick the one that makes the best prints for you
Yes it does affect how the negative turns out. More agitation pushes your highlight higher. Less, pulls your lightlights down.
The normal agitition method is first minute then 2 inversions every 30 sec.
Less agitation method is first minute then 2 inversion every minute.
^ Both of these methods are that I use depending on the rolls contrast. ^
So if you have a low contrast scene you would want to agitate more so you can push the highlights a little higher for more contrast.
But if you have a high contrast scene, you would want to agitate less to retain the highlights and less contrast.
It is because the developer for the highlights exhausts locally faster. So if you let it sit longer in-between inversions the highlight will not develop as much and will lower the contrast of film. (agitation does not affect shadows, within reason)
The opposite is also true. If you agitate more often, you will be giving the highlights new developer and it will develop more increasing the contrast.
Last edited by cjbecker; 02-15-2014 at 08:11 PM. Click to view previous post history.
For D-76 1:1, small tank, I definitely do agitation on 30-second intervals during development.
I will say that when I do it this way, for 35mm, I can measure differences between frames at the center of the reel versus the middle and the outside.
Stand development, if that's what you want to do... is a different story altogether.
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I'm not sure what developer you're using, but w/ D76 and most other developers (except Rodinal) I use 30 seconds of gentle swirly inversions, 2 gentle swirly inversions every 30 seconds, and none the last minute. Comes out perfect.
Last edited by momus; 02-16-2014 at 03:00 AM. Click to view previous post history.
Unless your agitation method is causing problems (streaking, uneven development, etc) then no, it does not really matter how you agitate the KEY thing is to be consistent. As you have seen from the previous replies, everyone has their own way of working. In my case, what works for me is:
Does it really matter how you agitate, so long as it's consistent?
- All chemicals always at 20˚C
- Two minute pre-soak.
- All stages up to the washing of the film with the same agitation method: four gentle inversions over the first 30 seconds followed by one gentle inversion every following 30 seconds.
- Washing is different as I use a variation of the Ilford washing method that involves constant inversions.
Whether the Stop Bath and Fixer require the same agitation is a matter of opinion that tends be as different as every photographer on APUG, I simply use the same agitation because then I don't have to think about it as every bath (I use a two-bath developer) receives the same agitation sequence.
So back to your question again, consistency and repeatability (rather than how you do something) are paramount. Once you consistently use a repeatable processing sequence you then can easily assess any given changes that you might want to make (such as reducing development time if your negatives are consistently too contrasty or increasing development time if your negatives have too little contrast) to adjust how your negatives come out and how easy they are to print how you want them.
Best of luck finding what works for you.
While this is true, most of us prefer to alter developing time and not agitation to achieve differences in contrast index. Varying time and keeping all other things constant is more predictable and repeatable.
Originally Posted by cjbecker
There are times when one wants a minimal agitation scheme, e.g., stand or semi-stand agitation, for a particular purpose; some use reduced agitation schemes exclusively. Even in this case, contrast control is usually accomplished by changes in developing time.
I would recommend to the OP that agitation be kept constant. I like the scheme with an initial 30 seconds of agitation followed by 10 seconds every minute as long as the negatives do not exhibit any streaking, mottling, etc. If that were the case, I'd agitate 30 seconds to start and then 5 seconds every 30 seconds thereafter.
Cjbecker gave you a good hint: agitation affects contrast of your negative. More agitation means more contrast, and less means less contrast—as long as you do not reduce agitation so much that you begin using semi-stand, or stand development, which are useful, but quite specialised, rather than general-use techniques, and as such they bring a whole raft of their own issues to deal with.
Similarly, you can influence the contrast by changing the duration of negative development: longer development means more contrast, less development means less contrast. In fact, changing the duration of development is the most common method of controlling the contrast of your negatives, whilst keeping agitation always the same. It is easier to predict continuous changes to contrast levels from development duration changes, than from somewhat discrete changes to agitation patterns. Zone System, BTZS, and many other time-tested approaches to negative contrast control, and the foundation of sensitometry (curves), and, of course, manufacturer recommendations by Kodak and Ilford, or equipment manufacturers like Jobo, advocate keeping agitation consistently same, and adjusting development time to achieve required changes to negative contrast.
If in doubt, do what the manufacturer has recommended. They want your images to succeed, because they realise that you are more likely to use their products if they gave you good recommendations that lead to repeatable, easy, error-free results.
PS. After I posted this, I noticed Doremus's post, with which I fully agree. Sorry for duplication...
Doremus and Rafal Lukawiecki
I fully agree and would also suggest the op to vary time instead of agitation to vary contrast. From the op question I kinda got into tunnel vision and never left it.
But knowing how agitation affect your outcome is a nice tool to have.