[alt-photo] Re: IDEA? NEW ALT PHOTO BOOK
Paul Viapiano
viapiano at pacbell.net
Fri Apr 23 19:32:33 GMT 2010
Here's my thought, FWIW (and that's not much)...
Fab EW is a highly sized paper already and adding PVA size is like gilding
the lily, and could sometimes be a bit too much for our purposes. As I've
said before, Keith Taylor uses Fab EW soft press and does not size (to my
knowledge) and has no staining or shrinkage problems with 3 layers.
Rives BFK, while sized, is still highly absorbent. That stuff just sucks up
emulsion like crazy, so maybe the PVA size gets absorbed into the paper
fibers better.
It would be interesting to try PVA size on unsized paper ala Arches 88 or
something like that.
Arches bright white, if I recall, is a pretty slick paper, seems very
heavily sized compared to the Rives, so maybe that's why it didn't work for
you.
Paul
----- Original Message -----
From: "Katharine Thayer" <kthayer at pacifier.com>
To: "The alternative photographic processes mailing list"
<alt-photo-process-list at lists.altphotolist.org>
Sent: Friday, April 23, 2010 12:23 PM
Subject: [alt-photo] Re: IDEA? NEW ALT PHOTO BOOK
> PS The only time I've seen something like what you're describing is when
> I was printing on Yupo, which reminiscence reinforces (to my mind) my
> suspicion that it's a problem of not having enough available tooth.
>
>
> On Apr 23, 2010, at 11:41 AM, Keith Gerling wrote:
>
>> A very nice summary, Katherine. However, can you explain this? In the
>> process of clearing the third or fourth layer of a print, I've had the
>> previous two or three layers suddenly go soft and slough off the surface
>> (or
>> at least threaten to do so. For instance, I might spray a print in an
>> effort to clear some highlight and see gum blow completely off the
>> surface
>> wherever a larger droplet might hit). I've never seen this happen
>> with
>> gelatin sized prints. in my experience, there has always been a
>> sacrosanct
>> understanding between me and the print, that a cleared, hardened and
>> dried
>> layer was "permanent" and would not loosen and go weak. Any amount of
>> scrubbing on further layers would not disrupt the previous hardened
>> layers.
>>
>> If the gum is attaching to the fibers, and not to the PVA size, then it
>> would seem that this loosening would not happen. The effect I observe
>> appears very much as if the PVA sits BETWEEN the fibers and the gum, the
>> PVA
>> softens, and the whole shebang lifts off. I don't think gelatin and PVA
>> size in the same way.
>>
>> Keith
>>
>> On Fri, Apr 23, 2010 at 1:08 PM, Katharine Thayer
>> <kthayer at pacifier.com>wrote:
>>
>>
>>> Whatever size is used, the gum attaches to the paper fibers rather
>>> than to
>>> the size, so the material used in the size shouldn't make any
>>> difference to
>>> how the gum adheres to the paper. Difficulties with size arise when
>>> the
>>> size becomes so thick or heavy that it clogs the surface fibers and
>>> leaves
>>> nothing for the gum to hang onto; then the hardened gum tends to slide
>>> off
>>> into the water. This is true whatever size is used, and this is why
>>> the
>>> optimal dilution of PVA size is different for different papers, because
>>> different papers have different surface qualities, and the size needs
>>> to be
>>> diluted enough that it soaks into the paper leaving surface fibers
>>> ("tooth")
>>> open for the gum to attach to. So no, the gum doesn't "sit" on top of
>>> PVA
>>> size any more than it does on top of a gelatin size.
>>>
>>> Paul: Since the unreacted dichromate and soluble gum wash off in
>>> development, there are no reaction products left in the finished and
>>> dried
>>> print, so there would be no purpose in exposing the dried layer to UV.
>>> IME, a print that's properly exposed and developed is entirely stable
>>> to
>>> rewetting. If soluble gum is left in the print, in other words if the
>>> print
>>> is removed and dried while there is still soluble gum in the paper,
>>> then
>>> that soluble gum will continue to dissolve and change the print when it
>>> is
>>> rewetted, but if the print is properly exposed and developed, there
>>> will be
>>> no undissolved gum and the print will be entirely stable to water,
>>> containting only hardened (insoluble) gum. If you think about it, the
>>> permanence of a gum print is a function of the insolubility of the
>>> hardened
>>> gum. If the print dissolves when wet, that's not a permanent print.
>>>
>>> Katharine
>>>
>>>
>>>
>>> On Apr 23, 2010, at 9:41 AM, Paul Viapiano wrote:
>>>
>>> Christina...
>>>
>>>>
>>>> These are all very good questions.
>>>>
>>>> Personally, I like to put down at least two layers before PVA sizing.
>>>> I
>>>> have noticed that the layer after the size has a harder time adhering,
>>>> hence
>>>> I should probably expose more or develop for less time. But then
>>>> again,
>>>> there are so many variables going on in any print, that I haven't
>>>> taken the
>>>> time to try and pin it down.
>>>>
>>>> I think that someone (Keith Gerling) also mentioned a while back, that
>>>> he
>>>> found layers were less stable when re-wetted. Would things be more
>>>> stable if
>>>> we exposed the print to UV after drying each layer? Just a thought
>>>> here...
>>>>
>>>> I don't know if the print really sits on top of the PVA any more than
>>>> the
>>>> gelatin. I look at it as just helping the already-sized paper along as
>>>> its
>>>> original size gets diluted with repeated soaking. This is all very
>>>> unscientific of me but is what I'm thinking.
>>>>
>>>> Paul
>>>>
>>>> ----- Original Message ----- From: "Christina Anderson" <
>>>> zphoto at montana.net>
>>>> To: "The alternative photographic processes mailing list" <
>>>> alt-photo-process-list at lists.altphotolist.org>
>>>> Sent: Friday, April 23, 2010 6:31 AM
>>>> Subject: [alt-photo] Re: IDEA? NEW ALT PHOTO BOOK
>>>>
>>>>
>>>>
>>>> Bob,
>>>>
>>>>>
>>>>> I think it could be a good thick chapter of a book...
>>>>>
>>>>> I am probably opening up a can of worms here...
>>>>>
>>>>> I've been using the Gamblin PVA size now and taught it to my class
>>>>> this
>>>>> semester in place of glutaraldehyde hardened 2.8% gelatin (6ml of
>>>>> 2.5% per
>>>>> liter), and it is a great teaching method and really user friendly.
>>>>> Boy was
>>>>> my life easier--no hot plate, massive sizing day, mess, toxicity.
>>>>> PVA you
>>>>> can just "size as you go". It is the "magic bullet" of teaching for
>>>>> sure.
>>>>>
>>>>> I use it 1+2 on Artistico. I found more issues with staining with
>>>>> PVA
>>>>> than with glut/gelatin but that I think is specifically related to
>>>>> having to
>>>>> determine the dilution of PVA for each specific paper. I almost
>>>>> think
>>>>> Fabriano might benefit from either a 1 + 1.5 or an intermediate layer
>>>>> of
>>>>> sizing between multiple coats. But at a point, then, PVA becomes too
>>>>> slick
>>>>> and plasticy.
>>>>>
>>>>> However, after having worked with it all semester I slightly prefer
>>>>> glut/gelatin. **But** I am not sure I prefer the latter enough to go
>>>>> to all
>>>>> the trouble to do it. With tray sized sheets gelatin is no big deal,
>>>>> but
>>>>> with 15x22 size sheets it is a pain. PVA wins, hands down, for
>>>>> user-friendliness.
>>>>>
>>>>> I will be finishing up two large gum projects this summer so we'll
>>>>> see by
>>>>> the end of summer how I feel--if I go back to gelatin in my own work,
>>>>> in
>>>>> other words. I will continue to teach the non-toxic PVA method, but
>>>>> parts
>>>>> of me think I should still at least show students traditional sizing
>>>>> because
>>>>> of a concern I am feeling.
>>>>>
>>>>> My concern is this: when I take a print out of the water to hang to
>>>>> dry,
>>>>> even the border of the print is what I would call "unstable"--
>>>>> meaning a
>>>>> fingerprint on it will mar it quite extensively in a way I have not
>>>>> seen
>>>>> with gelatin sized paper. Anecdotally, a rewetted PVA print SEEMS
>>>>> also less
>>>>> stable--layers still manipulatable. Is that an issue? I don't know.
>>>>> My
>>>>> question is does each layer you do of dichromated gum on top of a
>>>>> layer of
>>>>> previously hardened gelatin also affect the gelatin below (another
>>>>> colloid)
>>>>> and does it, in fact, affect a layer of PVA in the same way? Or can
>>>>> the
>>>>> layer of gelatin even GET rehardened repeatedly with each succeeding
>>>>> layer
>>>>> of dichromated gum or is it hardened once and for all with the glut
>>>>> and that
>>>>> is it--successive layers do nothing?
>>>>>
>>>>> Or is this just a "hydrophilic" thing, or that gum is (how would you
>>>>> say)
>>>>> "attracted" to PVA in the same way it is to a surface of gelatin?
>>>>> Are, in
>>>>> effect, PVA and gelatin truly interchangeable in sizing or is it
>>>>> possible
>>>>> that each layer of hardened gum has better adhesion to a layer of
>>>>> gelatin
>>>>> vs. a layer of PVA, probably only visible at the microscopic level?
>>>>>
>>>>> Maybe the scientists of the list can answer these questions and put
>>>>> my
>>>>> mind to rest, because my lurking fear is that the gum print on top of
>>>>> the
>>>>> PVA may not be as stable in the long run as one on top of gelatin. A
>>>>> non-scientific test I will do in a couple months is soak a PVA'ed
>>>>> print and
>>>>> a gelatin-sized print, old ones, side by side, and scratch and see
>>>>> the
>>>>> results. But I don't know if that proves anything.
>>>>>
>>>>> I hope someone will come on list and say this fear is completely
>>>>> unfounded, that both sizings create equally stable final prints. But
>>>>> I am
>>>>> worried the gum print sits on top of the size instead of melds into
>>>>> it.
>>>>>
>>>>> I have no answers, just asking the hard questions....on this quest
>>>>> for
>>>>> the most perfect, easiest size.
>>>>>
>>>>> Now, as far as other processes aside from gum....salt...hmmm....
>>>>>
>>>>> Chris
>>>>>
>>>>>
>>>>> Christina Z. Anderson
>>>>> christinaZanderson.com
>>>>>
>>>>>
>>>>>
>>>> _______________________________________________
>>>> Alt-photo-process-list | http://altphotolist.org/listinfo
>>>>
>>>>
>>>>
>>>>
>>> _______________________________________________
>>> Alt-photo-process-list | http://altphotolist.org/listinfo
>>>
>>>
>> _______________________________________________
>> Alt-photo-process-list | http://altphotolist.org/listinfo
>>
>>
>
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo
More information about the Alt-photo-process-list
mailing list