XTOL Again...

Renato Tonelli

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I would like to use XTOL at 1:3 for my Tri-X at 75F (Jobo ATL1500)
The Kodak tables show full strength and 1:1 only.
Is there a mathematical formula (+%) for figuring out the new times when changing the dilution and the temperature? Kodak used to have a very useful Developing Dial in their Darkroom Guide, but not the later edition.
Searching the forum, I noticed that a lot of users do indeed dilute it 1:3 and are happy with the results.
 

Peter De Smidt

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Originally, the Kodak PDF listed times for up to 1:3. I'm sure it's on my computer somewhere. If you PM me your email address, I'll send the PDF as an attachment. (You might also be able to find it online somewhere.) I used Xtol at 1+3 for years with great success.
 

john_s

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Also, FWIW, many of us would have the old Kodak pdf which includes those times. If you can't locate a copy, drop me a PM and I'll email it to you.
 

Helen B

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Peter,

Do you use rotary or inversion processing? I use 1+3 for inversion processing, but not for rotary because the lower tank volume would restrict the number of films I could develop at once without reducing the amount of stock per film.

Best,
Helen
 

Neal

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One small caveat when using the old data sheet. The developing times changed after Kodak moved to the new coating facility (at least I think that was the reason). You should compare the full strength and 1:1 times to move yourself to a closer starting point.

Neal Wydra
 

Peter De Smidt

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Hi Helen,

I used rotary processing, mainly 6 sheets of 4x5 in the 5x7 Jobo expert drum. I always used 1 liter of developer.

Regards,
Peter
 

Tom Hoskinson

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http://photo.net/bboard/q-and-a-fetch-msg?msg_id=008I2M

A claim is made in this thread that the development time varies as the square root of the (volume resulting from the) dilution.

For example: If your development time with undiluted D76 is 5 minutes. Your time for the 1+1 dilution would be (5)(sqrt(2)) = 7 minutes. Your time for the 1+3 dilution would be (5)(sqrt (4)) = 10 minutes.

I have not verified that this estimation method works.
__________________
 

Bruce Watson

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For continuous agitation (e.g. Jobo) time varies as the square root of dilution. For example, if your normal time is five minutes at 1:1, and you double dilution to 1:3, your new time would be 5(sqrt(2)) = 7 minutes.

For intermittant agitation like 35mm in small tanks or sheet film in hangers, time is more difficult to determine. Many people seem to like the rule-of-thumb that doubling dilution also doubles time. This will vary with the vigor of agitation of course.

For stand or semi-stand, all bets are off. You'll have to experiment and see.
 

Helen B

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Peter, thanks for the reply.

If anyone is interested: the Kodak times for stock, 1+1 and 1+3 Xtol with continuous agitation do not follow the square root rule of thumb - unless the value of root two varies between about 1.2 and 1.8. This is not a surprise because there is no real basis for such a simple, generally-applicable relationship. It's a good enough starting point in the absence of anything better.

Best,
Helen
 
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