Dick Sullivan says:
>>Terry King in error says:
>>Four pins, magic tape, heavy estar film ( or fix thin film to heavy duty
>>acetate), 140 lb paper and you will not need a substrate to remove your gum
>>print from !
I would not have said it if twenty years of practical experience had not shown
what I said to be true !
There are elements in the practice that Dick describes that give rise to the
difficulties.
>The substrate in gum does two things. One is that it stabilizes the paper.
>Paper when wet stretches and when it dries, it shrinks, and not always
>exactly the same.
If you dry pape rapidly with a hair drier, especially one where the heat is so
great that steam results, the paper is going to distort and shrink. I use a fan
heater which gives a steady stream of warm air that does not give rise to the
difficulties that seem to make a substrate necessary.
> The other is that it allows only one side to become wet.
>When only one side is wet it can be dried rapidly with a hair drier.
But then you have the diffficulties with the substrate that we have been
discussing.
> I found
>.that with the substrate, I could make very short exposures, with very short
>development times. We're talking here about 2 or 3 minute exposures and
>similar development times.
Obviously this depends upon the light source, but in my practice I would regard
an exposure of anything beyond three minutes, other than the first exposure with
very thin pigment, as being a gross over exposure. Shadow detail exposures are
going to be of the order of a minute to ninety seconds. An exposure of three
minutes at that stage consigns the print to the rubbish bin.
> With short exposures, short development and fast
>drying, I've had students make 8 to 10 coats on 4 or 5 or more prints in an
>evening workshop. The print can be built up in thin layers with absolute
>registration, the color and contrast can be adjusted in increments.
This is the bit I have never been able to understand. Me and my students make a
full range of tones, i.e. when necessary, every step on a step wedge, with
subtle gradations of colour with three coats or, rarely, four. I cannot see the
need for the extra coats that only add to the difficulties and, perhaps, make
the substrate necessary.
>Heavy paper is more stable than light paper, but when taped down, both sides
>get wet. Our experience showed that applying a hair dryer to a taped down
>gum caused the paper to buckle, and steam to push the print up in the
>center, the drying was not even and water would puddle in the buckles
>causing uneven development.
That is why I advise against using a hair dryer.
>In traditional gum making the tape mentod will work, but the substrate
>allows you do heretical things to the gum print.
I have some fun too. " The impossible takes until Tuesday ".
I am going to put some gums on photo CD so that people can see the evidence on a
home page.
Terry King
Bostick & Sullivan
1541 Center Dr.
Santa Fe, New Mexico
87505