[alt-photo] Re: On working with hydrochloric acid

[Mark Nelson]

I agree with Kerik!

Thanks Harlan!

I can't work around HCL at all. 

Mark Nelson
www.PrecisionDigitalNegatives.com
PDNPRint Forum @ Yahoo Groups
www.MarkINelsonPhoto.com

sent from my iPhonetypeDeviceThingy

On Feb 16, 2013, at 9:52 AM, Kerik Kouklis <kerik at kerik.com> wrote:

> Thanks for posting this Harlan!  I would encourage the use of oxalic acid for treating paper. I've been using this approach for well over 10 years with many hundreds of pt/pd prints and it works extremely well. 
> 
> Kerik
> www.kerik.com
> 
> On Feb 16, 2013, at 7:14 AM, Harlan Chapman <hchapman at coastside.net> wrote:
> 
>> A gentle warning on a sneaky little hazard in using hydrochloric acid
>> (muriatic acid):
>> 
>> The acidic component is a gas, hydrogen chloride (HCl). Even dilute
>> hydrochloric acid will liberate the gas into your working environment.
>> Within reason this doesn't present a serious toxicity hazard and with good
>> ventilation you will be fine - hydrochloric acid is surprisingly friendly
>> to work with considering it's strength. But nearly any metal (aluminum,
>> iron, copper, even most stainless steel alloys commonly used) in your
>> entire workspace, even across the room, will begin to corrode. The
>> corrosion will be slow, insidious and damaging. Once noticed you'll find it
>> everywhere. So don't work with HCl in a darkroom space that may include
>> valued metal objects like clocks, cameras, dry mount presses, cutters…
>> Don't use it in a stainless steel sink unless you know it is an
>> HCl-resistant alloy. And don't store concentrated (even dilute)
>> hydrochloric acid solutions inside unless double or triple packaged as even
>> the best sealed bottle will likely leak fumes slowly into your storage
>> space and destroy it.
>> 
>> Mix hydrochloric acid, use it, store it, and dry paper treated with it
>> freely outside.
>> 
>> The volatile corrosiveness of HCl largely is not shared with most other
>> acids commonly used in photographic/printing processes.  Oxalic, acetic,
>> citric, dilute sulfuric, and dilute nitric, are OK, they won't liberate
>> undetectable vapors that slowly chew on metals throughout your workspace.
>> 
>> Happy printing,
>> 
>> -Harlan
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