[rollei_list] Re: Nikor tank: Thing of Beauty
- From: slobodan dimitrov <s.dimitrov@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Thu, 6 Mar 2008 06:36:25 -0800
While I've used a variety of developers in the past, D76 1:1 has been
good to me.
However, when I tried using the narrow 220 reels, with either PXP220
or TXP320, they were constantly under developed. Even adjusting for
depletion, let's say 15% to 25% increase in time didn't help.
2 220 rolls in a standard 2 reel tank is the equivalent of 4 sheets
of 8x10. To say that this wouldn't strain the developer's capacities
is...well, let's say... dealing with the supernatural.
s.d.
On Mar 6, 2008, at 5:55 AM, Eric Goldstein wrote:
> Gentlemen, we'll disagree on this one, and I'll keep trusting what the
> manufacturers and motion picture labs I have used for years tell me...
> that you need a specified volume of developer per volume of film or it
> will be exhausted and fail, whether you are measuring the failure with
> a densitometer or not...
>
>
> Eric Goldstein
>
> --
>
> On 3/6/08, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>>
>> ----- Original Message -----
>> From: "Mark Rabiner" <mark@xxxxxxxxxxxxxxxx>
>> To: <rollei_list@xxxxxxxxxxxxx>
>>
>> Sent: Wednesday, March 05, 2008 8:08 PM
>> Subject: [rollei_list] Re: Nikor tank: Thing of Beauty
>>
>>
>>
>>> Developers do sometimes degrade rather quickly as in
>>> overnight.
>>>
>>> PH meters are a sure bigger help than densitometers.
>>>
>>> Control strips are the industry standard.
>>> Though not of course in small darkrooms.
>>>
>>> You'd just got to run you're own snippet!
>>>
>>> Snippet tests are even common with people bringing stuff
>>> to a big lab.
>>> Say six inches of the film you're shooting.
>>> See how it looks.
>>> If its thin they give it some more time. And visa versa.
>>>
>>> Super common in cinematography I hear.
>>>
>>> Test test test
>>>
>>>
>>>
>>>
>>> Mark William Rabiner
>>> markrabiner.com
>>>
>>
>> I completely disagree. A densitometer and calibrated
>> test strips tell you exactly what the developer is doing in
>> the practica sense that it requires developing some film.
>> Developers can go bad without any change in pH at all. Very
>> few developers fail suddenly, the notorious Xtol is a very
>> rare exception. The usual cause of developer becoming weak
>> without use is oxidation of the reducing agents from
>> exposure to the air. Using the developer does not "use up"
>> the reducing agents, rather, it results in an accumulation
>> of developer reaction products and bromide and iodide ions
>> from the emulsion, the latter acting as restrainers. Not all
>> developer reaction products act as restrainers either. For
>> instance those of hydroquinone act as accelerators.
>> BTW, according to some very competent chemical experts
>> pH measurement of photo chemicals, especially developers, is
>> rather difficult especially since the developing agents tend
>> to attack many common pH sensors. Ryuji Suzuki used to have
>> a rather extensive article on his web site but I am not sure
>> if he has rebuilt it sufficently to have it there again.
>>
>>
>> ---
>> Richard Knoppow
>> Los Angeles, CA, USA
>>
>> dickburk@xxxxxxxxxxxxx
>>
>>
>> ---
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