Re: Resinotype Mountain Revisited

[Alberto Novo <alt_list@albertonovo.it>]

Keith, 
> 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.
Well... it depends on the conditions you have in your room. 8-10% is a good 
choice for sizing by immersion (this method needs some viscosity), while 6% 
is better if you need to calculate the amount of solution.
An example: you have a 20x25 cm surface to coat at 35 g/m2.
20*5/10000= 0.05 m2 = 1.75 g gelatine/sheet
using a 6% solution this means 1.17:x=6:100 x=100*1.75/6= 29 cc of solution. 
A very manageable amount: use a 50 cc siringe and your error will be +- 1 
cc. 

> 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?
see above. 
> 2) what IS the "known volume" that you pour and for what size print?
see above. 35 g/m2 is what I found (for my taste) the best amout; 50 g/m2 
might be more comfortable if you are not already skilled in this art; higher 
amounts could require an higher percentage of gelatine (but if your room is 
cold you will see your gelatine settle under your eyes) or an higher amount 
of solution (and probabily you will see your paper dry in 2 or 3 days). The 
more the gelatine, the more you paper will curl; sugar may be added as an 
equal amount of the gelatine, but this will work only for the gelatinized 
paper. After it will soak in the water, it will loose the sugar and il will 
curl again. 
One of my first attempts with an hig amount of gelatine leaded to a 3 days 
before full dryness, and a strange thing looking like a "solid paper wave". 
> 3) do you think I would have successful results if I brushed on 3 or 4 coats
> of gelatin, letting it dry between coats?
If you are able to avoid bubbles, yes. I tried this method for a wide 
surface, but I was not able to achieve a satisfactory result. Moreover, I 
found tricky to calculate the exact amount of gelatine/m2 because the many 
coats required. 
> 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.
I use one of those aluminium tubs (I don't know how to describe them) used 
for baking or to pour things in the freezer. I pour my mixture (about 50 g 
pigment+rosin up to 150 g) iside the tub, and this over a double wire gauze 
(this for evenly distributing the heat under the tub) over my kitchen stove, 
slowly mixing the melting mixture with a glass or wood rod. 
When cool, the mixture is easily detachted from the aluminium tub. 
Alberto