>I just made my first few sheets of pigment tissue for carbon print. It is
>drying right now, so I haven't made print out of it yet, but I have a few
>questions / problems:
>
>1. I got lots of bubble, so much that it is impossible get rid of. I just
>left them there for now since this is going to be for exposure test only.
After you finish mixing up everything you need to set aside the warm
pigmented gelatin until all the bubbles go away. This can take anywhere
from 1-4 hours depending on how much you agitated the solution during
mixing. To keep the solution warm during this period of time place it in a
warm water bath in an ice cooler. Also, pour the coating solution on the
tissue carrier very careful because it is easy to produce bubbles at this
point also.
>
>2. About how much gelatine/water ratio do I need? The article in APR by Mike
>Shorter says 28 gr. gelatine in 460 ml water. That seems a little diluted.
>Another book uses 20 gr / 100 ml, which is quite thick. (I don't have the
>author's name because I only have a few xerox pages, but it mentions that the
>formula is based on 1938 edition of American Photography magazine). I started
>with something in between, 28 gr. / 320 ml.
The optimum %solution of gelatin depends very much on the bloom of the
gelatin. Hard gelatins of Bloom 300 or so will require only about a 6-7%
solution (that is, 60-70g of gelatin per 1000ml of water), while soft
gelatins of Bloom need about a 10-13% solution to have the same coating
characteristics. Also, the temperature of the coating room must be taken
into account. The cooler the room, the lower the %solution should be,
within the practical coating temperature limits of 65-75 degrees F.
In general, what is the effect of
>the amount of gelatine to the final print?
There is no easy answer to this question. It depends on how much pigmented
gelatin solution you use for a given coating area, type of pigment and
quantity, as well as the bloom of the gelatin. However, if you stay within
the useful coating range for any specific gelatin (5-8% for a hard gelatin,
9-15% for a soft gelatin) the answer is that there will be very little
difference in final image quality or printing characteristics
>In my first tissue, I didn't use glycerine, gum, or tween. I only added some
>syrup as plasticizer.
I can't say this won't work for you. I also tried it once but had some
trouble with the tissue, though it was so long ago the details escape my
memory.
>
Sandy King