[alt-photo] Re: cyanotype

[Mark Nelson]

You can count on at least one weird thing happening at every workshop!

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

sent from my iPhonetypeDeviceThingy

On Jun 2, 2010, at 6:37 PM, Christina Anderson <zphoto at montana.net>  
wrote:

> I have to tell another funny.
> BTW the chemistry is definitely not contaminated.
> BUT listen to this speaking of contamination:  We had a row of  
> prints hanging in the one darkroom. I mixed a tray of ammonia for  
> bleaching and tea toning (100ml household ammonia for 1 liter).  I  
> went out of the room, came back, and the FUMES from the ammonia had  
> changed all the prints hanging and still wet to lavender (not the  
> dry ones)!!! It was really pretty hilarious. So whenever I think I  
> have seen EVERYTHING under the sun with alt, something else like  
> this comes along.  Try it!! It's really a lovely purple.
> Christina Z. Anderson
> christinaZanderson.com
>
> On Jun 2, 2010, at 9:58 AM, Loris Medici wrote:
>
>> As for the "why?" I would suggest that you try to add a drop of 40%
>> citric acid into 10ml sensitizer and see if it gets better. If yes,
>> then it's probably chemical fogging (always more noticeable in the
>> highlights) due combination of increased sensitivity and paper
>> impurity (or sensitizer contamination?)...
>>
>> Regards,
>> Loris.
>>
>> P.S. Sorry for the "stuttering" postings...
>>
>>
>> 2010/6/2 Loris Medici <mail at loris.medici.name>:
>>> BTW, remember FAC is incredibly hygroscopic and deliquescent,
>>> therefore it's pretty normal that the paper doesn't want to get  
>>> dry in
>>> very humid environment.
>>>
>>> Regards,
>>> Loris.
>>>
>>>
>>> 2010/6/2 Loris Medici <mail at loris.medici.name>:
>>>> Christina that's my standard practice with cyanotype. I always  
>>>> expose
>>>> hot air force dried paper (after paper absorbed the sensitizer
>>>> completely that is - usually takes not more than 4-5 minutes...)  
>>>> for
>>>> sake of consistency. That way my exposure times and contrast remain
>>>> constant in all seasons / environmental conditions...
>>>>
>>>> Humidity increases sensitivity a lot and maybe that is causing the
>>>> chemical fogging (my interpretation) which doesn't kick in when  
>>>> you're
>>>> under a specific sensitivity threshold (with thoroughly force dried
>>>> paper)... ???
>>>>
>>>> Regards,
>>>> Loris.
>>>>
>>>>
>>>> 2010/6/2 Christina Anderson <zphoto at montana.net>:
>>>>> ...
>>>>> We've taken to blow drying the paper with blow dryers til  
>>>>> "snappy" to alleviate it.
>>>>> ...
>>>>
>>>
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