Rodinal - temperture transition formula, anyone?

[DGA]

It's damm hot in here these days.
Keeping 20°C is difficult.
My boiling mind starts looking for a solution.
Until recently I was using HC-110 solely, but someone gave me a bottle of
Rodinal for free (what a gift, hey).
I know that there is a temperature transition formula for HC-110 and I was
wondering if there is one for Rodinal as well.

The formula for HC-110, by the way, is:
New time = Old time × exp(-0.081 × (New temp °C - Old temp °C)) and it works great to me.
I took it from Michael A. Covington's wonderful wedsite

 

[FPjohn]

Hello:

The data sheet from Agfa gives time / temperature profiles. Apx100 1/50:18C, 14min; 20C, 12min; 22C 10min. gamma = .55

yours
FPJ

 

[FPjohn]

Your formula for HC110 is likely a good starting point.

 

[venchka]

The best time-temp chart

The best time-temp chart

This is the best. Bookmark it. Print it. Don't develop without it.

http://www.ilfordphoto.com/Webfiles/2006210208211880.pdf

Good luck!

 

[DGA]

Thanks, Wayne.
That looks promising, in deed.
But, isn't there a difference between developer types?

 

[FPjohn]

http://www.phototec.de/infomag_erechner.php

One stop Rodinol, and others, calculator.

yours
FPJ

 

[venchka]

Individual testing

Individual testing

Thanks, Wayne.
That looks promising, in deed.
But, isn't there a difference between developer types?

The Ilford chart tells you how to adjust time and temperature. You need to find your own time for a given developer. This forum has a lot of information on Rodinal and various films.

In the end you need to test for what you like.

 

[DGA]

http://www.phototec.de/infomag_erechner.php

One stop Rodinol, and others, calculator.

yours
FPJ

That is a good one.
I came across it once but never really used it
(though the times there looks reasonable, according to my experience)

 

[Mephiloco]

I've gone by the ilford chart and had no problems. I did a little math with it since I was developing at 80 F and stand developing. 1 hour became something like 28 minutes with inversions at 14 mins. Negs came out fine/great

 

[Mablo]

Wow! Big thanks venchka and FPjohn. Really good material.

 

[Fotohuis]

But, isn't there a difference between developer types?

To have the correction in density, no but indeed developers behaviour is different:

Rodinal (Para-Amino Phenol) is going to rise in grain when the temperature is higher therefore the best temperature for Rodinal is under room temperature let's say 17-18 degrees C is the optimum.
For you in Israel a big problem so you have to cool down the tank in ice cubes to prevent the temperature is running out of optimum specification.

Best regards,

Robert

(Working about 20 degrees C now in Holland)

 

[venchka]

Cross check your Rodinal times with the Massive Development Chart.

Here's another good item from Agfa. Bookmark it. Print it. Keep it with the Ilford time-temp chart.

http://unblinkingeye.com/Articles/Developers/Times_Rodinal/Rodinal.pdf

Good luck.

 

[Fotohuis]

That's a very old Agfa chart (from 1994). A lot of emulsions has been changed in the time.
Here a latest Rodinal chart from A&O (2007) but unfortunately with some failures in the APX100/400 (new).

http://www.fotohuisrovo.nl/documentatie/Rodinal.pdf

dilution 1+25 1+50

APX100 7 10
APX400 10 13

Greetz,

Robert

 

[DGA]

Funny.
One chart suggests 16min, other 14min and another - 12min.
All "official", all at 20°C.

Well, I just had to test it myself.
TX400 @ 400ISO, souped in Rodinal 1+50 @ 24°C for 11:30min gave me nice results
(at least that's how it looks like, hanged drying in my bathroom)

Conclusion - (you were right, Wayne) "In the end you need to test for what you like"

 

[venchka]

NOTE: all of the above times, for films and Rodinal developer, are suggesed starting times. For best results a test run should be made under individual conditions.

You collect data points. Assemble the pieces of the puzzle. Cross your fingers. Test.

Or use Diafine.

Take your pick.