[pure-silver] Re: Purple-Tinted Negs

I was also not able to measure a loss of shadow density until 8 minutes in
rapid fix. All my films are always fixed twice for 3 minutes.





Regards



Ralph W. Lambrecht

http://www.darkroomagic.com







On 2006-06-01 00:00, "Eric Nelson" <emanmb@xxxxxxxxx> wrote:

> Maybe the techs at Kodak Professional are crazy but
> they've told me several time that the "too long in the
> fixing bath" issue we were all taught to fear, is a
> myth insofar as film is concerned.  i.e. that the
> shadow/midtone whatever info would be lost/dissolved
> or whatever if fixed for too long.  They said they ran
> tests and fixxing could be as long as 6 minutes in
> Rapid Fix. 
> 
> Given that, I standardized with 5 minutes for fixing
> here, and; I NEVER fix more than 30 rolls per 1/2
> gallon, I use HCA with agitation (Jobo) for 1-3
> minutes. A minute is fine but longer won't hurt
> anything, and I NEVER have purple negs whether it be
> T-Max or otherwise.
> 
> Different films will have a different color.  PlusX
> looks blue for example, and a stack of processed Tri-x
> sheet film waiting to be sleeved has that purple
> color, yet individually the sheets look perfect.
> Eric   
> 
> --- Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
> 
>> 
>> ----- Original Message -----
>> From: "Adrienne Moumin"
>> <photowonder2010@xxxxxxxxxxx>
>> To: <pure-silver@xxxxxxxxxxxxx>
>> Sent: Wednesday, May 31, 2006 1:42 PM
>> Subject: [pure-silver] Re: Purple-Tinted Negs
>> 
>> 
>>> Belated & heartfelt thanks to all who took the
>> time to 
>>> respond, it took me a bit to bounce back after all
>> the 
>>> holiday weekend schlepping!
>>> 
>>> From her comments, I think my friend is using both
>> TMax 
>>> and Tri-X.  I think after all of everyone's help
>> she 
>>> shouldn't have the problem again!
>>> 
>>> As is often the case in life as well as
>> photography, an 
>>> answer begets another question in reference  to
>> this 
>>> excerpt:
>>> 
>>> The old rule of thumb still holds, measure the
>> clearing
>>> time and fix for double this time. The old rule is
>> also 
>>> that
>>> the fixer should be discarded when clearing time
>> doubles.
>>> This might be OK for a two bath system but IMO is
>> well
>>> beyond the safe limit for a single bath.
>>> 
>>> ---
>>> Richard Knoppow
>>> Los Angeles, CA, USA
>>> dickburk@xxxxxxxxxxxxx
>>> 
>>> 
>>> How does one know when the clearing time should be
>> 
>>> increased?
>>> 
>>> Thanks,
>>> Adrienne Moumin
>> 
>>    By fixing out a scrap of film occasionally. Use a
>> scrap 
>> of the film you originally tested with. Soak it in
>> plain 
>> water for 2 or 3 minutes (longer is OK) and then fix
>> it and 
>> watch to see when the cloudiness disappears. The
>> reason for 
>> soaking in water is that the rate of fixing for wet
>> film is 
>> different from dry film. Since the film is wet in
>> practice 
>> it should be wet when testing.
>> 
>>    Its important to understand that clearing is not
>> the same 
>> as fixing. The film can be visually clear and still
>> have 
>> enough halide left in it to cause trouble later.
>> However, 
>> the time it takes to clear is a good indication of
>> the 
>> amount of silver dissolved in the hypo.
>> 
>>    Another test is to use a solution of Potassium
>> Iodide. 
>> When this is added to fixer it combines with the
>> silver to 
>> form Silver Iodide in the form of a cream colored
>> cloud. The 
>> amount of dissolved silver which results in a cloud
>> which is 
>> not immedediately dissipated depends on the dilution
>> of the 
>> test solution. Kodak gives instructions for testing
>> both 
>> single and double baths but I think there is an
>> error in the 
>> instructions for the two bath system. I have not
>> been able 
>> to substantiate this. In any case, its easy to see
>> when film 
>> clears and its a more direct test.
>> 
>>    The degree of fixing can also be tested using a
>> solution 
>> of either Sodium sulfide or Kodak Rapid Selenium
>> Toner, 
>> diluted 1:9.   The Sulfide test is standard. KRST
>> can be 
>> used provided the film or paper is well washed
>> because it 
>> fails if there is a lot of residual hypo.
>>    A drop or two of the test solution is placed on a
>> clear 
>> area of the film or paper and allowed to stand for
>> about 2 
>> minutes. It is then rinsed off. There should be no
>> residual 
>> stain. Both Sulfide and Selenium will "tone" silver
>> halide 
>> or incomplete fixer reaction products as readily as
>> metallic 
>> silver so any stain will indicate the presence of
>> silver in 
>> some form. Since this method tests the actual
>> performance of 
>> the fixer it is probably the best test. When this
>> test is 
>> used on paper I suggest using a scrap that has been
>> processed along with the prints. The reason is that
>> prints 
>> or film that has been tested should be washed
>> following the 
>> test, which is, of course, not necessary when a
>> scrap is 
>> used. Also, the stain, if it develops, is permanent.
>> The 
>> film or paper can be re-fixed in fresh fixer but
>> refixing 
>> will not remove the stain.
>>    This residual silver test should be run on a
>> routine 
>> basis where permanence is of concern. Also, it will
>> show up 
>> prints that will give problems when toned ahead of
>> time.
>> 
>> ---
>> Richard Knoppow
>> Los Angeles, CA, USA
>> dickburk@xxxxxxxxxxxxx
>> 
>> 
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