[alt-photo] Re: Gum over cyanotype question

[Diana Bloomfield]

Yeah, I agree about the dichromate, but I also agree with Henry about  
too much sizing-- just use the sizing in the paper--  Early on,  
whenever I got flaking, it was because of too much pigment, though.    
Don't know much about a cyanotype base as I never use it, but why not  
just try a pigment for the cyan layer (to fix the cyanotype fading  
problem).  I've never understood using a cyanotype base for gum--  
doesn't it offer too intense a blue for the other layers (?).


On Feb 27, 2012, at 3:11 PM, Keith Gerling wrote:

> How long is the gum wash?  Could you have really hard water, with
> alkalinity that is bleaching the cyanotype?  Personally, I think  
> your level
> of dichromate is rather high, but then I've only used K.
>
> On Mon, Feb 27, 2012 at 11:23 AM, Willen, Matthew S  
> <willenm at etown.edu>wrote:
>
>> Yes, with gel/glut. Maybe it's to give it shot unsized. M
>>
>> On 2/27/12 12:07 PM, "Henry Rattle" <henry.rattle at ntlworld.com>  
>> wrote:
>>
>>> Matt - is your FA HP sized before the first coat? I sized with
>>> gelatin/formaldehyde before starting, and found this paper got  
>>> pretty
>>> slick
>>> after a coat or two.
>>>
>>> Henry
>>>
>>>
>>> On 27/02/2012 16:21, "Willen, Matthew S" <willenm at etown.edu> wrote:
>>>
>>>> Hi Francis
>>>> Fabriano Hot Press extra white, 300 lbs
>>>> Potassium, 1 part gum, part mixed gum/pigment, 2 parts Na  
>>>> dichromate
>>>> Gum exposure about 8 minutes under a bank of 12 uvbl bulbs.
>>>>
>>>> --Matt
>>>>
>>>> On 2/27/12 10:57 AM, "francis schanberger" <frangst at gmail.com>  
>>>> wrote:
>>>>
>>>>> These will probably help the discussion:
>>>>>
>>>>> What paper are you using?
>>>>> What is the gum sensitizer mixture? (ammonium or potassium  
>>>>> dichromate)
>>>>> (1:1
>>>>> or ?)
>>>>> How long is your gum exposure?
>>>>>
>>>>> -francis
>>>>>
>>>>>
>>>>> --
>>>>> francis schanberger
>>>>>
>>>>> www.francisschanberger.com
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