Re: pyro developed negs for cyanotype?

From: Diana Bloomfield ^lt;[email protected]>
Date: 10/31/04-06:31:37 PM Z
Message-id: <63F08650-2B9D-11D9-BE52-000A95DA8EE4@bellsouth.net>

Hi Sandy.

Thanks. I'll see if I can get him to send you one. He had a 3 ring
binder filled with beautiful 4x5 negatives..and we tried several
different ones, all with the same disappointing results. But that
would be helpful. By the way, I am assuming the coating on TMAX 100 is
not the same as for TMAX 400?

Diana

On Oct 31, 2004, at 7:08 PM, Sandy King wrote:

> Diana,
>
> The long and the short of it is that negatives that are well-exposed
> and developed in a pyro staining developer should not print any slower
> than negatives that are well-exposed and developed in non-staining
> developers.
>
> I strongly suspect that the problem with the Fujifilm is a UV coating
> of the type that TMAX-100 has. This coating, as others have mentioned,
> amounts to UV filtration of about log 1.00, or more than three full
> stops of exposure.
>
> I have never used Fujifilm but know of no reason other than UV
> filtration that could explain such long printing times for negatives
> that look good to the eye. However, I would be happy to test the film
> by taking a densitometer reading in UV mode if you could manage to get
> the gentleman in question send me one of his scratch negatives.
>
> Sandy
>
>
>
>
>
>> Thanks, Loris. We used the classic cyanotype formula. The white
>> vinegar bath did occur to me, along with diluting the sensitizer
>> itself at one point. The lights themselves get warm, but the
>> lightboxes had good fans that also kept the lights relatively cool
>> (not hot), and the other students were using the same lightboxes and
>> having no problems with longer than normal exposures. He also tried
>> the sun. So I'm thinking it's a combination of the Pyro and,
>> perhaps, Fuji b&w has this same UV blocking layer, like TMAX?
>> On Oct 31, 2004, at 6:25 PM, Loris Medici wrote:
>>
>>> Hi Diana,
>>>
>>> Don't know if you have already tried what I'm suggesting below but
>>> will write anyway (please forgive if you already know and/or tried
>>> these workarounds...)
>>>
>>> What formula were you using (classic or new cyanotype)? Have you
>>> tried acid development (white vinegar, 5% glacial acetic acid, 5% -
>>> or stronger - citric acid)? If the negatives are too contrasty for
>>> straight cyanotype formula (old or new doesn't matter) developing in
>>> acidic water may decrease the contrast of the paper (even you can
>>> try to add some acid to the coating solution... others: does this
>>> sound like a good solution?)
>>>
>>> If the problem isn't solely based on some sort of UV-blocking film
>>> base, acid development may certainly help - along with prolonged
>>> exposure times of course. But if the contrast is too high, even this
>>> modification may not help. Another point that comes to my mind:
>>> maybe you have to try intermittent exposures if you're using
>>> flourescent tubes. If they get too hot, their UV output is greatly
>>> reduced - which means that increasing the exposure times by 2 stops
>>> may not translate to a "real/practical" 2 stops increase...
>>>
>>> Regards,
>>> Loris.
>>>
>>> ----- Original Message ----- From: "Diana Bloomfield"
>>> <dhbloomfield@bellsouth.net>
>>> To: <alt-photo-process-l@sask.usask.ca>
>>> Sent: Monday, November 01, 2004 12:27 AM
>>> Subject: Re: pyro developed negs for cyanotype?
>>>
>>>> Thanks, Joe. This was Fujifilm, but I've never used b&w 4x5
>>>> Fujifilm, so I don't know how new it is, or whether it is suffering
>>>> the same fate with the film base as TMAX 100, but it sounds like
>>>> it. A 4 hour exposure would have been about right, I think!
>>>> ...
>
Received on Sun Oct 31 18:31:57 2004

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