Diffrence developing at 68 or 75deg?

[ezwriter]

So tonite its taking forever to get the chem bathtub down to 68deg. It started at 80, put in all
my ice and bottles and its now at 75deg.F.
Is there any neg difference developing at 75 compared to 68? Tmax dev. I know the time is different but negs would look the same?
thanks
ez

 

[ezwriter]

2- Before logging off, i hit Mark forums Read but when logging on again, still see old posts. Like Joke thread has 230 or so messages.
How do u just see new ones? thx

 

[BMbikerider]

I have always understood (and believed to a point) that if you developed at a higher temp than was recommended, there was a risk of enlarging the grain structure of the film. I don't mean developing for the same time as the approved temp but even shortening the time did run the risk of larger grain sizes. It may not happen with all films . For instance T Max films are always processed at I think 75 degrees instead of 68 and that has a very fine grain structure.

 

[Ian Grant]

I have always understood (and believed to a point) that if you developed at a higher temp than was recommended, there was a risk of enlarging the grain structure of the film. I don't mean developing for the same time as the approved temp but even shortening the time did run the risk of larger grain sizes. It may not happen with all films . For instance T Max films are always processed at I think 75 degrees instead of 68 and that has a very fine grain structure.

Grain itself isn't related to the processing temperature I process at 20° C (68°F) when in the UK and in the winter in Turkey and 27°C (80.6°F) in the Summer in Turkey with no differances.

It's important to keep the temperature consistent across all stages,a few films are more prone to issues if the temperature's not consistent at higher temperatures particularly with developers like Rodinal which contains Hydroxide.

Ian

 

[Roger Cole]

I develop all my film at 75F. I use a Jobo CPE2 and by using 75F I almost always can use the heater to warm to that temperature. It has no cold water inlet and I don't have running water in the darkroom anyway yet. As long as you adjust the time accordingly I've never seen a difference. Even on the warmest days of summer my solutions without the heater are at most maybe 76 and a slight adjustment takes care of that. The rest of the time I use the Jobo heater.

 

[johnielvis]

someone just asked this not too long ago--I have standardized on 75 degrees myself--

I have found (or maybe this is my imagination) that with stronger developers, the higher temp results in less fog development due to the shorter times---it's like the high temp gets the exposed stuff going quick and the fog (very little "exposure") doesn't get a chance to "catch up" like it would with longer development times--so you get higher smack--cleaner--it's just the shorter times are harder to control though...so that's the only tradeoff--you get less "repeatabliitly" with the shorter times because the dump and fill times become more critical--but if your dev times are over 5' it really shouldn't be a problem at all.--you'll SAVE time--less dev time.

 

[Bruce Osgood]

Do you warm water guy's have a reliable temperature conversion chart? If so, which one? I'm in the same boat as Roger Cole using the CPE2 and I depend on ice cubes to control temperature inside the drum and beakers but they inch up quickly.

 

[pentaxuser]

Bruce there will be plenty of answers to this from others but the Ilford site gives a chart for conversion of the 68F time to other temperature times. It is included with each of the developers on which Ilford gives its instructions. Obviously the chart is applicable to all devs

pentaxuser

 

[Ian Grant]

Do you warm water guy's have a reliable temperature conversion chart? If so, which one? I'm in the same boat as Roger Cole using the CPE2 and I depend on ice cubes to control temperature inside the drum and beakers but they inch up quickly.

I use a timer program on my PC Wlab/Dlab and that includes a temperature conversion pge, it's been fine for my film/developer combinations and I get consistent results. I have an accurate digital thermometer in Turkey and was surprised that working to the summer tap water temperature of 27°C I can keep within+/- 0.2°C for the whole process cycle.

Initially I tried cooling by refrigerating the chemistry, and ice cubes during processing, but with an ambient temperature of over 30°C this was very impractical.

Adox/EFKE films shouldn't be developed at the higher temperatures as the softer emulsion are prone to damage.

Ian

 

[Roger Cole]

Do you warm water guy's have a reliable temperature conversion chart? If so, which one? I'm in the same boat as Roger Cole using the CPE2 and I depend on ice cubes to control temperature inside the drum and beakers but they inch up quickly.

I use the Ilford chart. I've never had my temperatures above 77F even in the hottest part of this summer when it was 100F+ outside (darkroom is in the basement and though my house is on a sidehill and the basement has a door and windows that open to the back yard, the front side of the basement is underground and it stays fairly cool.) It's close enough for such a small change that I can't tell any difference from my standard times at 75F.

 

[Bruce Osgood]

I've found the large Ilford chart and downloaded it. I'm presently using 4X5 Delta 100 and Xtol (1+1) at 7:00 @ an intended 20C/68F and trying not to get times too short.

Thanks,

 

[Ian Grant]

Xtol works well at 1+2 if the times are too short.

IAn

 

[Roger Cole]

With inversion processing short times may be a worry, if you pour the chemicals in with the lights on and the film loaded. In that case, the thing to do is have the tank full of developer as you load film then drop the reel(s) in and hit the timer and put the lid on in the dark. If you want, you can also turn the lights off and take the lid off at the end of the cycle, lift the reel and plunge directly into another open tank of water or stop bath.

For others using Jobos with the lift I don't think short times matter, within reason at least. C41 first developer time is, what, 3.5 minutes? And we don't have problems with that (or at least I didn't back when I used it.) The tank is rotating as the liquid flows in over just a few seconds, same for pouring it out. Just be consistent with your timing as you work out your times (I hit the timer once I've poured all the liquid, but you can also start it as you start pouring, just do whichever the same way each time) and you'll be fine. I've never seen uneven development with times as short as 4 minutes.

That said, I wouldn't want to use 2 minutes or anything like that.