CIBACHROME
PRINTING
(make
your own easel for test strips)
By
John Pearle (Area 13)
Before
you can start making prints from a new packet of Ilfochrome paper
you have to find out what the response of the paper is to
filtration.
Maybe
you have done prints before and have made a note of your basic
filtration, then you can add your basic filters to the filtration
marked on the new packet, and you should then be able to print a
neutral grey, but it isn't that easy. Your basic filters are the
difference between those marked on the packet of paper and the
filters that you had to use to get a print with no colour cast.
If
you are starting from scratch you will have to find out what
filtration is needed to give you neutral grey - using your standard
exposure in seconds - with the enlarger head at a height that will
give you a 9" x 12" picture with an empty mount in the
carrier; previously focused with an ordinary slide in, of course.
So,
using the filtration on the packet you have to make several
exposures from, say f5.6; f8; f11; and f16 to see what the colour
balance is. You may have to change the filters several times before
you are satisfied, this can use up lots of paper. Tests can be done,
both for filtration or for exposure using a strip of paper 8"x
2"and a four exposure easel.
If
you are the least bit handy you can make one like the one Major
designed for us and that we have found to be very useful over many
years.
Here's
how. Start with a piece of hardboard 18" x 9". Cut it in
half down it's 18" length and then cut a
strip off the long edge of each piece. In the centre of one
piece make a hole 2" square (as diagram). Glue the strips along
the edges of the plain piece, on the smooth side of the hardboard,
and then glue the piece with the square hole in, smooth side down on
top making a long box with a hole in one side.
Now
you have to make the paper carrier. This is made out of thin card.
Cut strips 3"x 10½", 10½"x ½", 2½"x ½",
10"x ½",and two strips 3/8" x 10". Join them
all together as the diagram and glue a piece of cloth tape or a
bootlace about 40" long along the centre back of the paper
carrier.
Find
a ball bearing or a small bead and drill a hole into which it will
fit about 3/4" in from the outside edge of the hardboard cover,
level with the centre of the square window. The paper carrier should
slide into the hardboard cover with a length of tape at each end so
that you can pull the carrier in either direction. Now mark the
inside of the carrier into 2" sections and number each section
from 1 to 5 starting at the closed end. Pull the carrier through
until No.1 appears in the window and mark a spot through the
ball-bearing hole on to the edge of the carrier. Do the same for all
the other numbers and make a small indent where each spot appears.
This will give you an indicator, in the dark, as to where your piece
of cibachrome paper has got to. A piece of masking tape across the
top of the ball prevents it falling out and the pressure of your
finger on top of that will tell you when the ball has fallen into
the indent on the carrier and that a new piece of the test strip is
in the window.
In
use you will find that the strip can be used to judge the exposure
needed for extra dark parts of a slide to bring out detail and to
check that the filtration is right. There could be quite a variation
in colour balance at different stops.
The
test strip can be processed in your usual way.