Re: Resinotype Mountain Revisited

[Keith Gerling <keith.gerling@gmail.com>]

Hi Alberto,

Ok, now things are getting a bit confusing:

you say here "I started to pour a known volume of 6% gelatine over my paper" and "all these operations are the same for preparing a carbon tissue or a paper for oil printing"  

the original directions that I read at http://www.alternativephotography.com/process_resinotype.html state:  "choose a medium-weight 
            paper and seize it with a 8-10% gelatine solution, like for an oilprint."  Now, perhaps never having made an oilprint I am at a disadvantage, but it would seem that the volume of gelatine one would use to "size" is much different than that used to make carbon tissue.  Also, 6% is less than 8-10% by a considerable amount.

So, three more questions, and then I'll stop pestering you until after I actually MAKE one of these things:

1) what gelatin percentage to you recommend?
2) what IS the "known volume" that you pour and for what size print?
3) do you think I would have successful results if I brushed on 3 or 4 coats of gelatin, letting it dry between coats?

oh, one more question regarding pigment preparation:

what method do you use to melt the rosin/pigment mix?  Melting it in a spoon over a gas stove worked for a small batch, but with larger batch this doesn't work.  The heating is inconsistent throughout the batch and the rosin starts to smoke and burn.  

Thanks!

Keith

www.gumphoto.com

On 11/1/07, Alberto Novo < alt_list@albertonovo.it> wrote:

> First:- To make things really easy for those of us who do not
> have sophisticated electronic scales ( I DO have them ) could you simply
> state, in level teaspoons, the measures of rosin  to pigment powder?  I
> noted that Keith managed, somehow, to get the ammounts reversed.

I use both an electronic scale (0.1g) and a very old scale for document (0.5
g, one of those with a weight near the arm and a quarter of circle scale,
once used also for letters, 0-50 g and 0-250 g). So I am not used to measure
by volume. The proportion by weight is 4 parts of pigments and 10 parts of
rosin. This proportion may be changed adding more pigment if this is weak,
but increasing the ratio pigment/rosiny our powder will stain the highlights
more.

> From my own experiments the following might also help:-
> Stick your selected paper to a sheet of slightly roughened acrylic sheet
> with a solution of  warm  Gelatine 10gms to 100ml Water (10%) brushed on
> the back of  your  paper and smoothed out by hand with an interleaf of
> cheap paper to prevent soiling.  Directly following this the base coating
> ( the same 10% Gel) may be evenly brushed on and allowed to dry.  I have
> found that all of the subsequent stages, including sensitizing, are much
> easier to handle.  The completed print can be stripped from the acrylic
> when all stages have been completed.

The first times I coated the paper by immersion, but I ever had problems
with tiny air bubbles forming a few moments before the settling of the
gelatine :-(
Moreover, I find poorly repeatable this type of coating.

So, I started to pour a known volume of 6% gelatine over my paper. The most
important part is to have it over a perfectly leveled plane. Next, you may
simply spread the gelatine over with a proper tool. Or use a frame, fixed
with pliers, and pour your gelatine inside, etc.

I use a glass cutted slightly wider than my paper, where I deposit my wet
paper keeping it with my fingers at the opposite corners, so that there do
not form air bubbles. Check for bubbles looking at the read side. Then I
wipe off the excess water with an old windscreen wiper staring from the
centre, and finish the wiping with a paper towel again starting from the
centre.
I look after the air bubbles because they might rise the paper leading to a
different level of gelatine.

But all these operations are the same for preparing a carbon tissue or a
paper for oil printing...
And are again the same for sensitizing.

In this way, you will also become skilled for other two additional
techniques :-)

Alberto