Water temp > 68 deg F

Summertime, and my tap water is coming out a 75 deg F; I know I can

use refrigerated water or even ice to get the temp down, but I came

across this post from a couple of years back...Can anyone validate

this?? I suppose I could shoot a roll of film and try, but thought

I'd try here to see if anyone's attempted this.<p><p>

 

<i>Aaron Sussmans book from the late 60's "Amatuer Photographers

Handbook".<p><p>

<b>"Given the developing time at 68 degrees, you convert to the time

at any other temperature by multiplying the given time by the desired

temperature factor T. <p><p>

To convert from the time at any temperature other than 68 degrees, to

any other temperature, you divide the time of the given temperature

by its own factor and then multiply by the factor of the desired

temperature." <p><p>

Temp in Farenheit followed by factor <p><p></b>

<ul>

<li>64 deg F factor 1.23

<li>65 deg F factor 1.16

<li>66 deg F factor 1.10

<li>67 deg F factor 1.05

<li>68 deg F factor 1.00

<li>69 deg F factor .95

<li>70 deg F factor .90

<li>71 deg F factor .85

<li>72 deg F factor .81

<li>73 deg F factor .78

<li>74 deg F factor .75

<li>75 deg F factor .72

<li>76 deg F factor .69

<li>77 deg F factor .66

</ul>

from the ilford site:

</i> Thanks, RJ, Will, good info.

i forgot to add this....: i'm attempting to verify your factoring by taking the plots from the charts and matching them up. i'll let you know how it goes.

Careful. Different developers behave differently with temperature

change. The Ilford chart is for MQ and PQ developers. If you

go outside the range of the Ilford chart, things can change rather

dramatically, as the super additive effect changes (much less effective

at low temperatures, various effects at high temperatures).

 

The safest path is to download a datasheet for the developer you

are using, and look at what the manufacturer suggests.

oddly it worked quite well for me w/rodinal. spot on, actually. go figure.

Just tested a roll of Neopan 400, rated nominally, using XTOL 1+2 --Lex's favorite :-).

 

Massive Dev Chart lists this combo at 12min 30sec at 68 deg F; applying this chart for 75 deg F calcs out to 9 mins (factor .72)

 

Results look consistent with my usual results at 68 deg F.

As Richard says, it varies with the type of developer. As a rule of thumb and in the absence of better information I decrease dev time by 10 percent per degree C above 20 C (approx. 5 percent per degree F) and increase by 10 percent per degree C below 20 C. which corresponds to the above table. Rodinal is notably linear against temperature having a single developing agent but MQ formulations differently against temperature - the activity of quinol (hydroquinone) drops sharply below 18 C.

I'm using PMK Pyro and have found the recommendation from "The Book Of Pyro" to be correct, 4% per degree above 70f. I've developed Efke 25 at up to 82f with no trouble and even results.

 

Each developer may respond differently to temperature increase. If you have no other information, use the tables above. Otherwise, try finding the correct data for each developer if it exists. It is worth a bit of research and caution.