Film Grain and Agitation

[John Bragg]

Brain freeze, senior moment. But I did say I would have to check. 9 or 9.5 is correct for 1:1 and a condenser enlarger. So take off 20% from 9 and use EI 200. It will print the same. Multiply .8 times 9 for the answer.

What has to be balanced is you do not get too short and risk timing errors, although I can do color at 3.25 and that works fine. I did do monochrome one time at very short development cycle and it worked ok too.

I would urge anyone interested to try 1/2 box speed . I have never had anyone not be extremely pleased with the results.

I shoot at half box speed too and develop in HC-110 H instead of D76, Much like Charjohncarter.

 

[gns]

My time for ti-x (EI: 200) in d76 1:1 was 7.5 minutes. Always used 4 reel stainless tanks and did invert agitation (yes they did leak) continuous for first 30 seconds, then 2 inversions every minute.

I think the type of developer and the length of dev. time will affect grain much more than how you agitate.

 

[Photo_Smith]

How much agitation is best for minimal grain ?
will I lose contrast is I agitate less ?

I tend to do 5 inversions every 30 secs. (Tri-X ,TMY or TMX and TMAX developer)

do people use inversions or swirls/stirring ?

what works for you ?

What works best is consistency, start with the recommended agitation from the film or developer manufacturer. Your current regimen seems fine if a little on the over agitation side particularly as you state you use T Max developer which is quite an active developer with a low inertia point.

As for the question about which development/agitation will give minimum grain, that is a much harder question which will require a detailed answer (please roll your eyes and read another thread should the kinetics of development be of little interest)

Development
From the moment you finish pouring in the developer several chemical reactions occur; the gelatine swells developing agents come into contact with the gelatine and then the upper layer of grain, this point (15-30 seconds) is known as the inertia point as the grain isn't being reduced (developed) during this time constant agitation is recommended.

The next phase is when diffusion of developing agents reach the grain and start reduction, they are rapidly depleted at this point that action is proportional to the developer strength (and type) and amount of agitation and to some extent gelatine structure and to a lesser extent temperature.

During the following phase the silver releases a retarding agent called bromide which naturally slows development; to make this stage easier to explain (harder to predict) areas of the film that receive greater exposure exhaust the developer more rapidly and create localised areas of bromide concentration.
Less agitation at this stage can cause halo effects or 'Mackie' lines especially with less active and or diluted developers.

The relationship of chemical concentration, agitation and temperature are complex, for most common developers the diffusion coefficient decreases with increased concentration and the rate is not proportional to concentration, furthermore a change in temperature or solution p.h (less alkaline) can bring a transition from reaction controlled development to diffusion controlled–especially true with phenylenediamine (type) developers low in sulphite (which aids reduction).

Agitation increases development rate at this point as reduction is now underway and in most cases will increase contrast.
Ideal agitation maintains a fresh supply of developer agents at the grain interface between the emulsion and the bulk solution and maintains the reduction at that point allowing diffusion further into the lower layers.

So yes agitation will have an effect on both the chemical development of the grain and the appearance of graininess (in the user) and granularity (measured) other things effect these as well; some to a larger extent.

My advice is to be consistent and methodical, if the above seems like gobledygook then just go and take some pictures