Effect of temperature on development`

[nickandre]

Do higher temperatures increase grain size? I processed a test roll of rebranded (assumed HP5) film in D23 at 75 because it was still warm from when I mixed it. I think the grain was fairly large. Any explanation?

 

[Claire Senft]

Increasing development increases grain. Increasing temperature increases the rate of development. if the time and agitation remain the same and the temperature is increased then the development is increased and grain will be larger. If the time and agitation are reduced and temperature is increased it may be that the same overall development occurs. Will this mean that the grain remains unchnaged? Dunno.

 

[Anscojohn]

Hail to thee, Tiberius...
Those who love D23 salute you! The real experts might be able to better answer your question. Provided your film was not overdeveloped, one would reasonably expect the grain size to be the same no matter what the temp--within limits, of course. And D23 should react linearly to time/temp changes. Still, if the emulsion were softened a bit too much as a result of the high temp...........

 

[Martin Aislabie]

Ilford no longer sell their materials under other brand labels.

I believe this practice stopped with the management buy out

So, unless its old stock, it won't be HP5

Martin

 

[George Collier]

I would second John's suggestion that warmer developer would soften / expand the emulsion to a greater "degree" - (ha ha), therefore allowing the grains to move about more easily, clumping, etc., even if the temp is compensated for and contrast is normal.
You don't say what your normal temp is, but if it is 68, then maybe this is enough of a jump to see a noticeable difference?
Pure speculation, but makes sense.

 

[Bruce Watson]

Do higher temperatures increase grain size?

When I researched this a few years ago, I found that both Haist and Henry indicated that increasing temperature with all other things being equal (that is, the film ends up with the same gamma and same Dmax), film developed at a higher temperature will in fact be somewhat grainier.

That said, it's a minor effect. The primary determiner of graininess is the film itself. Next is the density you develop to -- graininess is directly related to density. Third is probably developer choice. Fourth would be effects from things like processing temperature.

Interestingly, agitation itself, all other things being equal (again, final result with same gamma and Dmax) appears to have no effect on graininess. People often think it does because if you increase agitation without a corresponding decrease in development time you end up with more density, and thus more graininess. But the added graininess isn't due to the increase in agitation, it's due to the increase in density.

 

[Ian Grant]

The increase in temperature also increases the risk of micro reticulation. This occurs when the differential between the temperature of processing stages isn't controlled tightly. It can lead to grain clumping rather than the classic old fashioned reticulation it's one of the reason why one person gets very fine grain with a particular film/developer combination, but another doesn't.

Ian

 

[nickandre]

About how many degrees of difference will cause micro-reticulation?

I developed it for the normal time at what I think came out to be 72 degrees. The DMAX was quite high compared to the film that the younger students were running through the developer.

The film was probably purchased back in January of last year and I froze it in March. The film was changed this year and now has the pink cast which I assume to be either TMAX or Trix.

I'm interested to try total development just to see how that would work. I have some of the Efke 25 which uses the old formulas from the 50s. Can anyone help me here? I'm told I develop enough rolls in it to dissolve silver in it and then just leave a roll in the developer for a few hours. Last time I did this by accident in Sprint chemistry I left it in the developer for 48 hours (I forgot about the roll) and ended up with grain the size of peas and the film didn't fix entirely. How often should I agitate?

 

[Ian Grant]

You should ideally keep within 1°C, (2°F), temperatures can drift, it's the shock of sudden temperature change that causes problems.

Ian

 

[optique]

Ian,

Would a temp differential (of 5 C.) in the post-fix wash put you in danger of micro-reticulation? IOW, is the wash stage part of the temperature sensitive process?

I ask because I normally wash with tap water which varies from the 20 C. of the other stages.

Thanks.
Steve.

 

[nickandre]

I think my stop/fix were 61 degrees...

 

[Ian Grant]

Ian,
Would a temp differential (of 5 C.) in the post-fix wash put you in danger of micro-reticulation? IOW, is the wash stage part of the temperature sensitive process?

I ask because I normally wash with tap water which varies from the 20 C. of the other stages.
Thanks.
Steve.

Yes the wash is part of the overall process, 5°C (approx 9°F) is quite significant, but you can allow the wash water temperature to drift slowly down over the wash cycle.

If you use the Ilford wash method it's easier to control the temperature.

Ian

 

[Martin Aislabie]

Ian,

Would a temp differential (of 5 C.) in the post-fix wash put you in danger of micro-reticulation? IOW, is the wash stage part of the temperature sensitive process?

I ask because I normally wash with tap water which varies from the 20 C. of the other stages.

Thanks.
Steve.

For at least half the year my wash water is sub 10C

To avoid reticulation, I minimise the thermal shock by running the tap water at the start of the wash cycle very slowly.

I start at a trickle and over about 5 minutes, I steadily increase the wash water flow rate.

Because of the low water temperature, I at least double the wash times recommended.

Martin