Re: pigment

Well, I just read through the whole text of handprint's discussion on
Prussian blue, which is most interesting; I recommend it to everyone's
perusal:

http://handprint.com/HP/WCL/waterfs.html

(Choose "blue" and scroll down to PB 27)

He says that the M. Graham PB27, the one I use, is the greenest of the
prussians, which is just another example of the rule that we should
never generalize from our own narrow experience-- I thought prussian
was too green to be good for tricolor, but that may well be true only
of the M. Graham prussian and not of prussian in general. He also says
that the fading and color shift historically has been in paints where
white extenders have been used; it can perhaps be assumed that the
paints which test as totally permanent do not contain these extenders.
  But read it for yourself.

Katharine

On Nov 22, 2005, at 8:30 AM, Katharine Thayer wrote:

> Well, that's interesting isn't it. If it's the same compound, as
> Jack or someone said, then why would it be permanent as a cyanotype
> and not as a pigment? And why some brands permanent and others not?
> (And no, contrary to popular myth, this is not true of most pigments;
> this is the only one I know of where the variability of permanence
> across brands is worth noting; usually the brands vary by only a
> couple of point on an 8-point scale.)
> Katharine
>
> On Nov 22, 2005, at 7:38 AM, Marek Matusz wrote:
>
>> All,
>> This question of cyanotype or prussian blue permanence has beem
>> lingering in literature for a while. Yet there are plenty of examples
>> of perfetly good looking cyanotypes from hundred years ago. I have
>> been conducting my own stability tests on the pigments that I am
>> using. I t has been a couple of months and we do get a lot of sun
>> exposure in Texas. I will report which pigmets do well in a few
>> months (prussian blue from Daniel Smith is one of the pigments
>> tested).
>> Marek, Houston
>>
>>
>>> From: "Christina Z. Anderson" <zphoto@montana.net>
>>> Reply-To: alt-photo-process-l@sask.usask.ca
>>> To: alt-photo-process-l@sask.usask.ca
>>> Subject: Re: pigment
>>> Date: Tue, 22 Nov 2005 07:05:29 -0700
>>>
>>> I'm going to throw out something here you all can hash over.
>>>
>>> I don't use Prussian blue just because of some brands' purported
>>> fading in sunlight and recovering in the dark...Maimeri, Sennelier,
>>> Schmincke, Wand N...
>>>
>>> Page says she has not seen it recover.
>>>
>>> Whether this is fact or fallacy, thalo works so much better with
>>> more color saturation and clearer and smoother. But it seems to me
>>> that this chance would be akin to working with Alizarin nowadays
>>> when there are better, permanent reds.
>>> Chris
>>>
>>> ----- Original Message ----- From: "Jack Fulton"
>>> <jefulton1@comcast.net>
>>> To: <alt-photo-process-l@sask.usask.ca>
>>> Sent: Monday, November 21, 2005 10:15 PM
>>> Subject: Re: pigment
>>>
>>>
>>>> Yes, the 'blue' of the cyanotype is Prussian Blue. The cool thing
>>>> about it is that it was the first true blue that was what one might
>>>> call inexpensive. It came around in the early 1700's, so Herschel
>>>> knew all about it when developing the cyanotype.
>>>>
>>>> One interesting anecdote for today's climate of terrorism is that
>>>> Prussian Blue and Potassium Iodide can be ingested to aid in the
>>>> removal of radioactive materials from the body. Both of these are
>>>> chemicals of our medium. The FDA approval of Prussion Blue is
>>>> either coming up or was recently approved. The U.S. is stockpiling
>>>> capsules of it.
>>>> Jack Fulton
>>>>
>>>>
>>>>
>>>> On Nov 21, 2005, at 8:49 PM, Katharine Thayer wrote:
>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Nov 21, 2005, at 6:55 PM, Dave Rose wrote:
>>>>>
>>>>>> Isn't Prussian Blue the same pigment/chemical that forms
>>>>>> cyanotype prints?
>>>>>
>>>>> Is it? I guess I've never heard or thought about what the final
>>>>> product is that forms a cyanotype print, but Prussian blue is
>>>>> hydrous ferric ferrocyanide or feriammonium ferrocyanide, is that
>>>>> what it is?
>>>>>
>>>>> To my eye, Prussian blue pigment has a greener cast to it than
>>>>> most cyanotypes I've seen, or than pthalo, which to my eye has
>>>>> probably the purest cyan hue for tricolor of the blue pigments
>>>>> available, followed by ultramarine. And to me it's a duller blue
>>>>> than either pthalo or ultramarine, and for those two reasons I
>>>>> didn't suggest it for tricolor. But I can't say for sure that
>>>>> it's not good for tricolor, because I've never tried it. I guess
>>>>> I was also influenced by someone who wrote the other day that he
>>>>> had tried Prussian for tricolor and it didn't work well at all.
>>>>>
>>>>> I feel another test
>>>>> kt
>>>>>
>>>>
>>>
>>>
>>
>>
>
Received on Tue Nov 22 11:38:04 2005