[rollei_list] Re: OT: development
- From: Allen Zak <azak@xxxxxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Fri, 20 May 2005 23:34:00 -0400
On May 20, 2005, at 7:01 PM, Richard Knoppow wrote:
>
> ----- Original Message -----
> From: "Allen Zak" <azak@xxxxxxxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Friday, May 20, 2005 3:06 PM
> Subject: [rollei_list] Re: OT: development
>
>
>>
>> On May 20, 2005, at 4:21 PM, Richard Knoppow wrote:
>>
>>>
>>> ----- Original Message -----
>>> From: "Bob Shell" <bob@xxxxxxxxxxxx>
>>> To: <rollei_list@xxxxxxxxxxxxx>
>>> Sent: Friday, May 20, 2005 12:17 PM
>>> Subject: [rollei_list] Re: OT: development
>>>
>>>
>>>>
>>>> On Friday, May 20, 2005, at 02:57 PM, James Davis
>>>> wrote:
>>>>
>>>>> Sorry to follow myself up, I presume that the Ilford
>>>>> equivalent (for my
>>>>> local store stocks Ilford) is Ilford Wash Aid? It's not
>>>>> clear from
>>>>> their
>>>>> literature that it's sulfite based.
>>>>>
>>>>
>>>> I never use a wash aid with film. Fixing the film
>>>> longer
>>>> and washing
>>>> properly will get rid of any residual dye. The wash aid
>>>> won't hurt
>>>> anything, but I don't think it is really necessary. I
>>>> do
>>>> use it on
>>>> fiber based paper prints, though.
>>>>
>>>> Bob
>>>>
>>>> ---
>>> It has the same benefit for film as for paper in that
>>> it
>>> makes some othewise insoluble fixing reaction products
>>> soluble, or at least releases them when they are bound up
>>> to
>>> image silver or the gelatin. This has the effect of
>>> extending fixer capacity and insuring complete fixation.
>>> Wash aid also helps to conserve water where that is
>>> desirable by reducing film washing time from 30 minutes
>>> to 5
>>> minutes.
>>>
>>> ---
>>> Richard Knoppow
>>> Los Angeles, CA, USA
>>> dickburk@xxxxxxxxxxxxx
>>
>> Ilford recommends fixing with non-hardening rapid fixer,
>> no wash aid,
>> then washing with a technique that usually takes about 5
>> minutes or
>> less and uses about three pints (@ 1.5 liters) of water
>> per roll of
>> film, assuming SS Nikor style tanks and reels. That's
>> what I have been
>> doing for the last decade or so. It is probably too early
>> to determine
>> how well my negatives will last, but I'm also old enough
>> to not really
>> care. Fortunately, my earlier B&W was processed strictly
>> to Kodak
>> specs, which included a wash aid ( Perma Wash) and
>> therefore will
>> outlast all meaning.
>>
>> Allen Zak
>>
>> ---
>> Rollei List
>
>
> I am not certain what is in Perma-Wash. At least one wash
> aid on the market seems to be composed of a detergent. I
> have no idea if this stuff works. I have the vaguest memory
> of reading an article or paper on detergents as wash aids
> long ago but have not seen anyting recently. Lets say I am
> suspicious of it.
> The test for completeness of washing is the Silver
> Nitrate test. There are others which are most sensitive but
> the Silver Nitrate test will show whether the prints have
> excessive hypo in them. The method is very simple but a more
> elaborate version, in which the stain spots are fixed, can
> be used with a densitometer for quantitative measurements.
> All this stuff is in Kodak literature somewhere.
> Ilford's procedure is premised on the idea that fixing
> time should be so short that hypo can not work its way into
> the paper fibers. Washing is a diffusion process except for
> this condition of paper base. Once the hypo becomes adsorbed
> onto the interstices of the fibers they tend to bind there
> and it is at least partially a frictional process to remove
> them. Sulfite acts as an ion exchange for thiosulfate so
> tends to force it out of the fibers. Ilford found that if
> the fixing process could be completed in less than a minute,
> preferably in no more than 30 seconds, the hypo did not
> become bound up in the fibers. After 2 minutes the deed is
> done and washing must be done conventionally. One problem is
> that no all paper will fix out in one minute or less.
> Ilford recommends a ten minute treatment in sulfite wash
> aid followed by a five minute wash. Ilford also has a water
> saving method of using successive baths of water. Kodak has
> a similar regimen but Ilford's probably uses less water.
> Such a system of successive baths can give perfectly
> archival washing but has no advantage over running water
> other than conservation of water and utility where running
> water is not available.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
The procedure I described was for film, upon which there is no
absorption of fixer other than the emulsion. Quickie paper fixi/wash
seemed suitable for RC but more problematical with FB, so for those I
stayed with standard methods. Perma Wash was pretty common way back
when, probably because it came packaged as a liquid and was more
convenient to mix than KHCA. Most large volume processors around here
used the stuff.
Allen Zak
---
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