processing temp.??

[stradibarrius]

What differences would you expect between using the correct time for 68f and the correct time for 79f when processing.
By correct time I mean either the manf. recommend time or "your" correct time.
Is there an advantage or drawback from using the "correct time" at a higher temp. opposed the the longer time and a lower temp??

 

[Ian Grant]

There was thread about similar issues last month, some of us living in warmer climates have issues in the summer so use up to 25-27°C

You need to be more careful as emulsions will soften more, the major problem is making sure all your chemistry & washing is as the same temperature, although that's sometimes less of an issue as indoor ambient & tap water temps are often about the same. Variations in processing temperatures may cause micro-reticulation which is really grain clumping, and that's far more likely to occur at these higher temperatures.

There's no quality differences or increase in grain etc between my negs processed at 27°C here in Turkey or those made in the UK or winter here at 20°C.

As long as you can control all the temperatures then there's no disadvantages, it's not really worth it just to save time.

Ian

 

[tkamiya]

I am having this very problem at this moment. I use XTOL for film. According to Kodak literature, any time shorter than 5 minutes is not recommended for it may produce uneven results. For my film (Tmax 400), 80F is not recommended as processing time is shorter than 5 min. You might want to check if your chemical has any restrictions as such.

At higher temperature, the development time shortens. I think, that means any variation in your timing have greater effects in result (ie. over/under development).

 

[Ian Grant]

I am having this very problem at this moment. I use XTOL for film. According to Kodak literature, any time shorter than 5 minutes is not recommended for it may produce uneven results. For my film (Tmax 400), 80F is not recommended as processing time is shorter than 5 min. You might want to check if your chemical has any restrictions as such.

At higher temperature, the development time shortens. I think, that means any variation in your timing have greater effects in result (ie. over/under development).

That's a good point short times make the time it takes filling/emptying a a tank more critical and you need to balance these issues.

Ian

 

[Mike Wilde]

Then there are the developing agent issues; for instannce, glycin is very slugish to develop at anything below 75F. So if there is glycin in you mix, you will need to fine tune a time for the use at the higher temperature; the relationship is not easily mathematically predicted.

 

[Sirius Glass]

Ilford has time/temperature charts so that you can adjust to the current temperature from the 68ºF.

Steve

 

[Bruce Watson]

Then there are the developing agent issues; for instannce, glycin is very slugish to develop at anything below 75F. So if there is glycin in you mix, you will need to fine tune a time for the use at the higher temperature; the relationship is not easily mathematically predicted.

Yes. I've read that the different developer agents have activity curves (with temperature) that are somewhat different. For example, hydroquinone may be more active at lower temperatures than metol. This in turn may change your effective film speed somewhat, and the tonality of the image, again, somewhat.

If you balance out speed and contrast using the tools you have available (like dilution, agitation, time/temp, etc.) then two films exposed the same way at the same scene, one developed at 20C and one at 27C, should look very similar. But they may not look exactly the same, depending on the developer (and it's agents). The question is, will they look enough the same for your purposes? And only you can decide that.

More discussion available on the photo.net thread Myth #12 Processing Temperature.