Re: Sizing paper with gum and dichromate, was Re: glut

On Dec 15, 2005, at 3:18 PM, Yves Gauvreau wrote:

> Katharine,
>
> I wouldn't say that just yet because I wasn't exposing for clear gum,

Okay,

> I was
> trying to get as many steps as possible and for this I exposed for up
> to 2
> hours which is about 30-60 times more that what you usually do if I
> recall
> correctly. I fact I wasn't even using gum at some point, just
> exploring the
> dichromate by itself.

Well, I'm not sure what you're doing when you do that. I thought I
proved to myself some years ago, by painting dichromate on glass,
drying it and putting it out in the sun until it turned brown, that
the dichromate gets reduced whether there's any other material there to
pass it an electron or not. But I've been told that's impossible, so
I'm not sure what to make of what I saw. But when you expose dichromate
on paper, it's almost certain that the dichromate is reacting with
something in the paper, and not just with its own self; that's why I
did the experiment on glass, because I knew that I wouldn't be able to
interpret any result on paper as having only to do with the dichromate.

>
> As for being curious, well I plead guilty your honor. Though I find
> this a
> bit weird that the gum universe is so poorly defined and understoud
> compared
> with other process, it wont stop me, at least not yet.

That's good. Understand that it's not that some of us haven't been
working very hard to figure it out for a long time, and it's not that
we're all idiots, honestly, or that none of us is curious, it's just
that it's not that simple.

>
> Maybe you could start thinking about the day when someone will ask you
> "What
> makes a "gum print" a gum print???" I'm sure the person who will
> interview
> you someday will find something much better then this to ask you but
> I'm
> sure you get the idea.

Actually I thought I had answered that question, when I said in
another discussion that my study of the mechanism of the gum process
has made me understand that the gum process is all about the
crosslinking of gum. Nothing more, nothing less. And what makes a gum
print a gum print, IMO, is the croosslinked gum. The pigment makes a
gum print VISIBLE to a viewer, but it's not what makes a gum print a
gum print, or what makes a gum print interesting, IMO. To me, that's
the beauty of it.

I almost hesitate to say that again, since I have been so thoroughly
misunderstood when I've said it before, but I can't help it if people
are determined to misunderstand me. I'm not saying that you don't have
to understand pigment and how pigment and gum work together, in order
to become a gum printer. That would be a ridiculous thing to say, and
it's not anything I've ever said. All I'm saying is that the structure,
the mechanism, the image, is entirely constructed of crosslinked gum.
You can make a gum print without pigment (although you can't see it
very well unless it's stained with dichromate) but you can't make a
gum print without gum. That may seem simplistic, but to me it was a
profound insight that has made everything about gum printing easier and
more understandable.

Just a suggestion: It might help our communications run more smoothly
if you wouldn't assume that I and the rest of us here had never
considered these questions before. Or, for that matter, that I haven't
already been interviewed about gum printing many times. (And no, they
don't ask interesting questions like that, at all,).
Katharine

>
> ----- Original Message -----
> From: "Katharine Thayer" <kthayer@pacifier.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Thursday, December 15, 2005 11:56 AM
> Subject: Re: Sizing paper with gum and dichromate, was Re: glut
>
>
> Hi Yves,
> I'm sorry, I don't have a clue why I get clear gum and others don't. I
> used to think it had something to do with the light, but it sounds like
> you didn't get clear gum with the same light, so that's not it. I'm
> about out of ideas for why things happen in gum, at the moment. I know
> you want definite answers for all your questions, and I applaud your
> curiosity and persistence, but definite answers that generalize to the
> universe of gum printers and gum printing are very few and far between.
> All I know, and all I can say, is what works for me, and I'd say that
> your best bet, if you really want to learn gum printing, is to set out
> and see what works for you. That's just how it is with gum, sorry,
> Katharine
>
>
> On Dec 15, 2005, at 6:46 AM, Yves Gauvreau wrote:
>
>> Hi,
>>
>> thanks to all who replyed to my question. I'd like to add, Katherine
>> showed
>> us a gum dichro layer that at least from the scan I've seen didn't
>> show any
>> apparent color like Kees and Loris mention. Maybe she could tell us
>> the
>> "secret" of getting a clear unstained gum layer. From what she said I
>> think
>> it's all a question of exposure but I've been known to misinterpret
>> her and
>> others writing before, thus maybe it's better to wait for her own
>> words on
>> this.
>>
>> Thanks again
>> Yves
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Kees Brandenburg" <ctb@zeelandnet.nl>
>> To: <alt-photo-process-l@sask.usask.ca>
>> Sent: Thursday, December 15, 2005 9:26 AM
>> Subject: Sizing paper with gum and dichromate, was Re: glut
>>
>>
>>> Loris, Yves and others,
>>>
>>> I tried gum sizing too and got the same greenish stain that would not
>>> clear even after a long(er) disulfite bath and wash. Probably I
>>> overexposed. But why not standardize things a little bit more and
>>> size
>>> with gum and expose with your standard printing time through a clear
>>> sheet of printing substrate (or film). I'll give that a try this
>>> week. I
>>> do like my gelatin/formalin or gelatin/glyoxal sized papers but
>>> there's
>>> allways a different 'feel' in the first (gum on gelatin) and the
>>> subsequent (gum on gum) coats.
>>>
>>> -kees
>>>
>>>
>>>
>>> Loris Medici wrote:
>>>
>>>> IME, the practice of sizing with gum has the risk of dichromate
>>>> staining
>>>> unless you expose very carefully. When I coat the paper with
>>>> unpigmented
>>>> gum + dichromate mixture and expose it 30 secs without the negative
>>>> +
>>>> contact printing frame combo (my normal exposure with negative and
>>>> contact printing frame is 360 secs / 6 mins. In other words: I
>>>> expose
>>>> the unpigmented gum + dichromate mixture ~ 3.5 stops less when
>>>> sizing...), I get a slightly greenish / grayish surface (very slight
>>>> and
>>>> subtle, but you can see it clearly), not paper white. Probably I
>>>> should
>>>> expose less in order to get rid of the stain (or reduce it further)
>>>> but
>>>> if I do so, I may get suspicious about the effectiveness of the
>>>> sizing.
>>>> Therefore, I size with gelatine and harden in formalin. (BTW, I
>>>> should
>>>> admit that: I never tried to use paper sized in that manner - I mean
>>>> for
>>>> gum printing, I didn't like the cyanotypes I've made on paper sized
>>>> with
>>>> gum dichromate - and dumped that method when I saw the stain + my
>>>> bad
>>>> experience with Cyanotype... I also didn't tried to establish a
>>>> non-staining exposure time - I guess I was lazy back then).
>>>>
>>>> Regards,
>>>> Loris.
>>>>
>>>> -----Original Message-----
>>>> From: Yves Gauvreau [mailto:gauvreau-yves@sympatico.ca]
>>>> Sent: 15 Aralık 2005 Perşembe 14:31
>>>> To: alt-photo-process-l@sask.usask.ca
>>>> Subject: Re: glut
>>>>
>>>>
>>>> Hi,
>>>>
>>>> out of curiosity, would there be a "problem" sizing with gum instead
>>>> of
>>>> gelatine especially if you intend to do gum printing later???
>>>>
>>>> Yves
>>>>
>>>> PS Aren't we suppose to sent our message in plain text...
>>>>
>>>>
>>>>
>>
>
Received on Thu Dec 15 21:31:56 2005