[alt-photo] Re: Sulfite + Na4.EDTA clearing bath quick kitchen formula?

[Loris Medici]

Exactly! (Here's your post: http://www.apug.org/forums/viewpost.php?p=913735)

Thanks for sharing, it's reassuring to know you're using this
particular formula for such long time. I was testing clearing Masa
paper (w/ Li variant of pop pd process) the day before, and found that
a simple (and very mild) citric acid first rinse followed by 1 dessert
spoon sulfite + 2 dessert spoons of Na4.EDTA into ~ 1500ml works like
a charm. Just wanted to be prepared for worst case scenario...

Thanks again,
Loris.


24 Şubat 2012 18:32 tarihinde Keith Schreiber <keith at jkschreiber.com> yazdı:
> Hi Loris,
>
> I may be the source of that particular kitchen formula. I've mentioned it here several times over the past decade and it is also on the formula page on my website. The original source of the formula was Howard Efner who used to be active on the list, though I don't remember if I got it from him directly or if he posted it here himself. As Howard explained it, the order that the ingredients are mixed matters because the citric acid converts the tetrasodium edta into the disodium form, so be sure they are dissolved fully before adding the sulfite.
>
> I don't think that the proportions are critical within limits. There are probably chemists here who could show how to balance it perfectly, though Howard himself was a chemist by profession.
>
> I've been using this formula successfully for at least 10 years now and have found no need for anything more complicated or convoluted. Sometimes I have mixed it with a little more or less water to decrease or increase the strength for certain papers - a bit weaker for Bienfang 360 or a bit stronger for Twinrocker WC, for example.
>
> Cheers,
> Keith
>
> Keith Schreiber
> keith at jkschreiber.com
> www.jkschreiber.com
>
>
> On Feb 24, 2012, at 12:36 AM, Loris Medici wrote:
>
>> Thanks Philippe!
>>
>> Out of curiosity, I found a formula that says:
>>
>> 2 Tbsp Na4.EDTA
>> 1 Tbsp citric acid
>> 1 Tbsp sodium sulfite
>>
>> The EDTA:sulfite proportions are reversed here, I guess it's not
>> critical - as long as they're together. Do you have any experience
>> with a formula similar to the above?
>>
>> Regards,
>> Loris.
>>
>>
>> 23 Şubat 2012 14:36 tarihinde Philippe Ayral <payral at gmail.com> yazdı:
>>> In my work I use 20g sodium sulfite per liter (should be a heaping
>>> dessert spoon) plus a half one for EDTA.
>>> It works for Arche Platine.
>>>
>>> 2012/2/23 Loris Medici <mail at loris.medici.name>:
>>>> Anyone with a quick kitchen formula for sodium sulfite + tetrasodium
>>>> EDTA clearing bath for pt/pd? (I mean something like: 2 dessert spoon
>>>> sulfite + 2 dessert spoon EDTA into 1000ml water...)
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