[alt-photo] Re: Chlorox Bleach Development of Gum

[Katharine Thayer]

I can attest that ammonia works well for hastening development in  
gum.  I have always kept a bottle of household ammonia (no flavor,  
scent or detergent added of course, just ammonia)  by the sink to  
gently flood across areas that need a little nudging, like when I  
don't have the time or patience to wait for shadows to open up on  
their own. Works in a flash.
Katharine


On Jan 13, 2010, at 11:04 AM, pfriedrichsen at sympatico.ca wrote:

>
> Has anyone tried using an alkaline bath instead of the bleach?.
>
> I haven't tried the bleach development but I have been working with  
> "gum" subing gelatine, or casein, and the print clears more readily  
> as the
> developer is made more alkaline. Salts I use are Sodium Bicarbonate  
> for a mild alkaline  solution pH of about 8, or Sodium Carbonate  
> with a solution pH of around 10.
>
> A dilute bleach solution that I made up using about 200 ml water to  
> 20 ml household bleach gave me a pH of 11.2. This is very alkaline.  
> From what I understand, an alkaline pH changes the charge of  
> particles and cellulose, so they start to repel each other hence  
> the alkalinity of most detergents.
>
> This would be good because it would avoid the use of hypochlorite  
> which is hard on cellulose fibers. This is just a hunch.
>
> At 08:21 AM 01/13/2010, you wrote:
>
>> And another one, which Loris already kindly answered, but might be
>> interesting to draw attention to below method again anyway..
>>
>>
>> Cor
>>
>>
>>
>> .....................
>>
>> Last night I played a bit with gum over platinum, I made an exposure
>> mistake, and seriously over exposed a cobalt blue gum layer. After a
>> night long soak/development I saw barely some development this  
>> morning.
>>
>> Than I recalled below method as originated from Marek and  
>> described by
>> Loris.
>>
>> I was wondering about one thing: when you do the bleach step, do you
>> keep the gum layer towards the solution, just like a "normal" water
>> developing step, or do you place it image side up and gently rock the
>> tray.
>>
>> I assume the first?
>>
>> Thanks & best,
>>
>> Cor
>>
>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>
>> RE: Miracle size for gum (chlorox bleach development)
>>
>> From: Marek Matusz <marekmatusz at hotmail.com>
>> To: alt-photo-process-l at usask.ca
>> Date: 14 Oct 2009 - 3:30p.m.
>>
>> Loris,
>> A very good description and a starting point for experimentation. I
>> usually keep my bleach concentration on the low side (20cc/liter),  
>> but I
>> actually no longer measure the exact amount. Just like a cook adding
>> salt to the dish without measuring how much, I just pour some bleach
>> into the tray. Interesting part of the process is that I had some  
>> test
>> strips that I ried to develop overnight and there were still not  
>> quite
>> there yet after 12 hours. A 30 second bleach soak followed by 10  
>> minute
>> water development made just perfect test strips.
>> Marek
>>
>>
>>   _____
>>
>> Date: Tue, 13 Oct 2009 17:12:29 +0300
>> From: mail at loris.medici.name
>> Subject: RE: Miracle size for gum
>> To: alt-photo-process-l at usask.ca
>>
>>
>> Bleach development, in short, is developing by adding small amnt.
>> (20-40ml into 1000ml) of household bleach into the development  
>> water. It
>> was brought into attention by Marek Matusz a couple of years ago.  
>> See my
>> procedure below, I'm sure Marek will describe his and/or add more
>> information later:
>>
>> * Prepare two development trays, one with bleach and one without.
>> * Use a generously pigmented coating solution; a pigment amnt.  
>> that you
>> would not normally use.
>> * Expose longer; I use 2x-3x-4x times the normal. (Test!)
>> * Put the print in the plain water bath to let the unreacted  
>> dichromate
>> ooze out, refresh the water few times and drain until the print is  
>> clear
>> of dichromate. There will be no (or almost none) development action.
>> Refresh the water again.
>> * Put the print into the bleach bath and wait for a pre-determined  
>> time
>> such as 1-2 minutes. (Test!) The print will start to develop.
>> * Drain and put the print in the plain water bath, the bleaching  
>> action
>> will continue for some time. Check 5-10 minutes later, if the
>> development speed/amount is consistent with the norm (I mean what you
>> experience with normal prints after 10 minutes of development),  
>> change
>> the water and continue to develop in plain water. Or, put the print
>> again in the bleach batch to further trigger/speed up development,  
>> but
>> keep the bleaching time short this time (15-30 secs), once  
>> triggered the
>> development is very quick in the bleach bath.
>> * Put the print in the plain water bath and continue by bringing back
>> the print to the bleach bath if further more is necessary. You got  
>> the
>> idea!
>>
>> You can use this method to save overexposed layers too - works  
>> most of
>> the time. It's my most useful tool in workshop situations, saves time
>> and motivation! :)
>>
>> Using this method, you can print very dark one-coat prints which have
>> convincing blacks. In other words: "subtlety and drama at the same
>> time"... (See Marek's recent step tablet tests.)
>>
>> As I said before, I'm sure Marek will add to the information above  
>> (or
>> correct it).
>>
>> Hope this helps,
>> Loris.
>>
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