[alt-photo] Re: IDEA? NEW ALT PHOTO BOOK

[Christina Anderson]

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

On Apr 22, 2010, at 8:54 PM, BOB KISS wrote:

> DEAR LIST,
> 
>            I have been faithfully reading most postings on this list since,
> I think, 1998.  Many, many postings have been very informative about the
> amazing number of options for sizing many different kinds of paper for the
> many alt processes.  I really think it is time for someone to collate all
> this info into a new alt photo book.  I hereby propose that the title be,
> SIZE MATTERS.  Any takers (as it were)?  ;-))
> 
>                        CHEERS!
> 
>                                    BOB

> Please check my website:  <http://www.bobkiss.com/> http://www.bobkiss.com/
> 
> "Live as if you are going to die tomorrow.  Learn as if you are going to
> live forever".  Mahatma Gandhi
> ______________________________________________
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