Re: pyro developed negs for cyanotype?

Hi Diana,

That is correct. TMAX-400 does not have a coating that causes UV filtration.

Sandy

>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 20:43:19 2004