U of S | Mailing List Archive | alt-photo-process-l | Re: Wood panel preparation (Keith?)

Re: Wood panel preparation (Keith?)

Hi Keith,

Yes, I'm a little bit meticulous because I have little time devoted to
printing, therefore I don't have the luxury of trial and error, without
risking motivation loss that is... ;)

That sizing seems pretty weak. (My usual for paper is 3%) Will calculate
by measuring the weight of half tablespoon gelatin -> that should be
pretty close since we have the same stuff. What if I don't size? (I'm
pretty sure you have tried this.) Will that work also?

I was afraid of long soaks therefore I ordered marine grade plywood (which
is very resistant to water - no warping, no veneer coming apart...), it's
not expensive (considering the material) -> I ordered 25 13x17" sheets, it
will cost me only USD 48, including cutting the huge raw sheet to size.
(Makes less than USD 2 per sheet, and that's cheaper than fine quality
watercolor paper!)

At your printing size smoothing actually takes something (tactility?) from
the prints but I prefer to work on smaller scale which makes a smoother
surface a necessity.

See the aluminum sheet I just finished to gesso here:

It was shot under oblique incandescent light, exaggerating the texture.
(The field of view is something like 4x6" - just to give you an idea of
the magnification. 4 layers of acrylic gesso with calcium carbonate,
applied with a foam brush.) Ground formulation as following: 40g gesso +
80g CaCO3 + 80ml water.

I like the texture, will sand half only of the sheet and see how each side
behave... The surface is very nice, feels very absorbent and soft to the
touch -> very similar to an eggshell. (That's fine I presume...)

Scotch pad idea is great -> will try that first. Yes, I'm concerned about
the dust -> I don't think Elif will appreciate it! :)

Thanks again,

24 Şubat 2009, Salı, 5:40 pm tarihinde, Keith Gerling yazmış:
> Well, here is where we may go our separate ways, because we are
> meticululous and me?... not so much!
> Sizing Strength:  I don't actually know.  I use a half tablespoon of
> Jelatin (Toz - no idea of the bloom) to 450 ml water to which I add
> about 3 ml Gluteraldahyde.
> Coating:  I'm using two surfaces at present.  MDO is a very smooth
> plywood used for signs and for boatbuilding, but I'm not sure if it is
> actually "marine grade".  MDF is a heavy pressed wood.  MDO is very
> smooth so it takes three coats of the affore-mentioned gesso.  MDF
> requires only two.  I'm sure a roller would be great.  I prefer a big
> rough brush, as I like the brushstrokes.  I do not sand, as this
> provides a surface that is too smooth and perfect.  Something tells me
> this is the method you will prefer :)  - When I did sand I just used a
> rough screen -  the type used for smoothing drywall plaster, or a 3m
> scotchpad green thing - sandpaper made a big mess - the pumice powder
> got into everything.
> 2009/2/24 Loris Medici <mail@loris.medici.name>:
>> Thanks Keith! As I understand it, I need to increase the whiting amnt.
>> in
>> my preliminary formula, since I choose to mix equal *weight* of acrylic
>> gesso with whiting (50g gesso + 50g CaCO3), but you say equal
>> *volumes*...
>> That was good to know. Thanks for the info about sizing.
>> Few more questions:
>> - What is your sizing solution strenght?
>> - What is your coating method? (Detailed description please; how much
>> layers? exact application method and procedure? - crossing fingers: I
>> want
>> to be able to coat with a foam roller...)
>> - Do you sand the acrylic gesso before sizing? If yes, how? What is your
>> exact procedure?
>> I feel like leaving the "traditional gesso" plan behind, it's too much
>> complicated for my liking -> I may resort to it if everhing else fails,
>> but I'm afraid it has its own problems as it looks like a method that
>> should be mastered - painfully!
>> Thanks again & regards,
>> Loris.
>> 24 Şubat 2009, Salı, 4:22 pm tarihinde, Keith Gerling yazmış:
>>> Hi Loris!
>>> The #1 formula you present is very similar to the one I use with great
>>> success:  1:1 Liquitex acrylic gesso to water and then to that 1:1
>>> dilute gesso to pumice by volume.  That produces a surface that acts
>>> very similar to paper, so I size it with gelatin and hardener.  This
>>> mix is very good for coating porous surfaces such as wood, plaster
>>> (spackle-ed wood) and old gumprints on paper.  For surfaces such as
>>> aluminum and glass, bubbles of water tend to form between the surface
>>> and the gesso with long soaks.  For these surfaces I do not use
>>> acylic, preferring to mix up a concoction of gelatin, pumice and
>>> marble powder.  I haven't used this in a while and I haven't reduced
>>> it to a recipe, but essentially it is a gelatin mix (the same as used
>>> for sizing paper) with 50% pumice and marble.  It produces a surface
>>> that is so hard that it is actually very hard to remove even with a
>>> belt sander!
>>> Hope this helps
>>> On Tue, Feb 24, 2009 at 2:30 AM, Loris Medici <mail@loris.medici.name>
>>> wrote:
>>>> I will try to print gum on wood panels (marine grade plywood). I will
>>>> try
>>>> two different grounds: 1) Acrylic ground + whiting (I presume that's
>>>> what
>>>> you do Keith?) 2) Traditional gesso ground...
>>>> 1) Keith, what is your acrylic formula? I plan to dilute acrylic gesso
>>>> 1:1
>>>> with water and then add equal amnt. of calcium carbonate (marble dust)
>>>> and
>>>> some white pigment into it. For instance: 50g acrylic gesso + 50ml
>>>> water
>>>> +
>>>> 50g calcium carbonate + 10g titanium dioxide (titanium white -> purest
>>>> /
>>>> brightest white pigment).
>>>> 2) Traditional gesso: 100ml water + 10g hide (or rabbitskin) glue
>>>> (high
>>>> bloom gelatin) + 60g calcium carbonate + 12g titanium white.
>>>> I need a good working recipe and application (and finishing) procedure
>>>> for
>>>> #2. BTW, traditional gesso is a PIA! (Have to keep it hot + it doesn't
>>>> set
>>>> quickly, so takes awfully long to complete 4 - 6 layers...)
>>>> Another questions:
>>>> 1. Do you harden the traditional gesso ground?
>>>> 2. Do you add a hardened gelatin layer on top of the acrylic (or
>>>> traditional gesso) ground?
>>>> Thanks in advance,
>>>> Loris.