U of S | Mailing List Archive | alt-photo-process-l | Other PVAc primers/sealers. (Was: Miracle size for gum.)

Other PVAc primers/sealers. (Was: Miracle size for gum.)

Hi David,


I emailed the makers of Unibond, who incidentally are in the same road as my chemical supplier, and received this:


Thank you for your enquiry

Unibond Waterproof PVA is a bonding agent for the building industry and is only waterproof when mixed with cement. In it's own right it is not waterproof and cannot be used directly under waterbased paints or such materials.

We trust the above helps to answer your request.


Mike Lill
Technical Services Department
Henkel Consumer Adhesives
Tel: +44 (0)1606 593933


I had asked for a small, (25ml), sample to try as I don’t really want to buy a tub and find it doesn’t work. I’ll have to look for a friendly builder. What they describe as waterproof might be much more than is needed for gum sizing though. While I can’t test at the moment though as my light box is in bits, I’ll coat a sheet of paper with regular Unibond and soak it over night to see what happens.






From: davidhatton@totalise.co.uk [mailto:davidhatton@totalise.co.uk]
Sent: 12 October 2009 14:11
To: alt-photo-process-l@usask.ca
Subject: RE: Miracle size for gum


Hi John,

This is probably a better bet


as it dries waterproof .



On Oct 12 2009, John Brewer wrote:


I think it's a good idea Judy does try what PVA she has at home as I will
too. I have some Unibond,
(http://www.makingdiyeasier.co.uk/unibond/pva.html) which is PVAc used in
the building industry. I'll try it when I get some time in a week or so.
Gamblin PVA can't possibly be the only PVAc in the world that works, surely.

BTW both PVAL and PVAc are 'glues' among other things.


From: Paul Viapiano [mailto:viapiano@pacbell.net]
Sent: 12 October 2009 06:08
To: alt-photo-process-l@usask.ca
Subject: Re: Miracle size for gum


Gamblin PVA Size is what you want...go to Utrecht...don't bother with
anything else.

I do have PVA adhesive here at home and I use it for bookbinding. It's a


----- Original Message -----

From: "Christina Z. Anderson" <

To: < alt-photo-process-l@usask.ca>

Sent: Sunday, October 11, 2009 6:40 PM

Subject: Re: Miracle size for gum

> ----- Original Message -----
> From: "Judy Seigel" < jseigel@panix.com>
>> Sometimes I have trouble staying out of an argument, because who doesn't
>> love a good argument? Research shows, moreover, that an argument about
>> firms the skin and makes the hormones flow, while discouraging outsiders
>> from attempts to muscle in on the process. But the gum argument (or
>> "discussion") I'm staying out of now is because I don't know what the
>> folks are talking about & decline to expose my ignorance.
> Judy,
> I hear ya, I hear ya...I agree in that testing and arguing about gum
> get gum printers or gum prints made. The proof in the validity of gum
> testing comes in the work produced, IMHO. Now, that will open another can

> of worms--what constitutes a "good" gum print and I daren't touch that
> a ten foot pole. But there are a lot of excellent gummists who never pick
> a step wedge. They just make prints.
> I find it extremely useful that when we discuss things as tonal range,
> miracle size, more or less dichromate, more or less exposure, etc. we find
> way to talk apples to apples in gum, and that is where the lowly step
> comes into play for me--scientific or not, used and discussed correctly or

> not (thanks, Etienne).
> Thus when a statement is made that such and such produces a longer tonal
> range, I take it to mean that the maximum "black" for that color pigment
> been reached (obviously not black as in a glossy silver gelatin) as well
> paper white has been achieved, and those steps in between can be counted
> compared to get somewhat close to apples to apples. Either the step wedge

> shows just a few steps, or lots of steps. And each step on the step wedge,

> being film, is a difference of 1/3 stop or 1/2 stop that corresponds to
> increasing or decreasing hardening of gum, whether that hardening equates
> not to a measurable log of density.
> When gum gets a bad rap as being a "two stop process" which, I assume, the

> writer meant there were only 4 **steps** of color on the step wedge or 6
> a 31 step (writer is well known, and certainly gum has a reputation of
> a short scale process), then it is important to discuss what kind of tonal

> range people who gum print frequently are getting. I personally don't
> gum THAT short scale of a process. Certainly not as tonally long as
> platinum but long enough.
> But as has been found in this discussion, as usual anything gum, the
> parameters of the testing is different from gummist to gummist and
> no longer compares apples to apples anyway. And then we get into arguing
> over how many angels dance on the head of a pin.
> And then it's interesting to see your advice come back to you--or not.
> Seems to me a while back on this list I dared to suggest that past a
> point more dichromate wasn't necessary--it didn't decrease exposure enough

> to warrant the extra amount and I settle now on an easy to measure 15% am
> (used to use 7.5%, one list member only uses 2.5% and her exposures are
> lengthy). That by a step wedge. Wow did I get creamed in that
> Seems I also mentioned that using EQUAL strengths of ammonium, sodium, and

> potassium dichromate had different speeds--ammonium being the fastest, and

> for all the solubility that sodium has, it doesn't have much oomph--more
> like potassium at the same strength (used 10% for all). That I found by a

> step wedge. I know at least Sandy King corroborated and even gave a
> percentage comparison between am and pot di. Oh, and Kosar as well...but
> man, the first time I mentioned Kosar I was creamed.
> So even though using a step wedge on a process that really isn't
> photographic in a sense (just photosensitive) and talking about it in
> photographic terms, that step wedge sure is a handy little thing...
> OH, and having been cleaning out my dimroom all day, I finally found my
> motherlode of step wedges. I had lost them I thought permanently, and
> ordered 3 more 4x5s and 1 8x10, and NOW I have a passelode of the things,
> heheheheh. I just love this cleaning thing. For some reason I had put
> under a towel on top of which I let gum prints dry before exposure.
> Back to size, Marek, I am going to run right out and buy that miracle
> lemmetellya. If I could find a nontoxic size that also printed a LONG
> RANGE (gasp) I will personally come down to TX and kiss your cheeks!! And
> Jeremy Moore, that video thing is a great idea to do for the list! Good
> discussion...
> Chris
> __________________
> Christina Z. Anderson
> http://christinaZanderson.com/

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