A Bostick & Sullivan Research Project
The Ziatype was developed in the Labs of Bostick & Sullivan.
I was looking for a better way to control color and contrast in
a palladium or palladium-platinum printing system. About 20 years
ago I tried Guiseppe Pizzighelli's printing out process developed
in the late 1800's without much success. In the mid 1980's Dr. Michael
Ware developed a variation of Pizzighelli's POP process which has
enjoyed a loyal but small following.
This process is also a variation of Pizzighelli's process. It uses
lithium palladium chloride as the primary metal and ammonium ferric
oxalate for the iron compound. In the Pizzighelli and Ware's processes,
color and contrast are interlocked and controlled largely by humidity.
In the Ziatype the color and contrast are controlled chemically,
making for a much more controllable and flexible printing system.
The Ziatype has undergone some changes in the past year and will
more than likely see more in the future. We here at B+S are striving
to constantly improve our products and the Ziatype is one of our
The Advantages of the Ziatype:
A printing out system. Images can be evaluated as they print. In
most cases the first print will be successful. Far fewer underexposed
or overexposed prints.
Greater contrast control without graining. Normal silver negatives
made for printing on No. 2 grade paper can be printed.
Greater paper acceptance. It tends not to be finicky and prints
well on most papers.
Greater color control. You can "dial in" various shades
of brown and red brown, purple and grays.
Greater printing speed. As much as 3 stops in some cases.
No developer needed.
Cold neutral black color with pure palladium. The elegance of a
Frederick Evans print with palladium.
Good Dmax without the use of costly platinum.
Your kit will contain:
|Ferric ammonium oxalate sol. 1
|Lithium palladium chloride sol. 3
|Ammonium dichromate sol. 2
|Sodium tungstate 40% sol. 4
|Tween 20 10% sol.
|Citric acid clearing agent
MATERIALS you will need to provide:
UV light source -- the sun works nicely
though a little unreliable at times
Coating rod or brush
Contact printing frame
Protective mask or respirator
5 eyedroppers, one for each solution.
1 mil to 3-mil Mylar sheets
All processing should be done under yellow bug light or very
low illumination. The Ziatype appears to be a little more sensitive
to ambient light in the printing room than the conventional platinum
and palladium process. Though there may not be any visible fogging
in the print, incipient fog might compress the midtone values.
For an 8x10 print start with 15 drops (about 1 ml) of ferric ammonium
If you want a warm brown tone, add 1 or more
drops of sodium tungstate sol. No. 4. Three drops will make a very
warm sepia print. When you add the tungstate solution to the ferric
ammonium oxalate a slight precipitate will form. Swish the solution
around for a moment and it will dissolve. (If it is added after
the lithium palladium solution is added it will be harder to dissolve
Now add an amount of lithium palladium Sol.
No. 3 equal to the amount of ferric ammonium oxalate No. 1.
If a neutral gray color is desired, use only
the lithium palladium sol. No. 3 and ferric ammonium oxalate No.1
together in equal amounts.
Adjust contrast by adding small quantities
of ammonium dicromate sol.2 (1 drop per 8x10 is quite a bit so you
may wish to dilute the dicromate solution with water for finer control.)
1 drop or more of 10% Tween 20 ™ may
be used to adjust the absorption qualities of the paper. This will
vary according to paper and conditions. It is an emulsifier and
surfactant. It aids in spreading the emulsion and helps it penetrate
the sizing of the paper. If the paper forms darkish areas during
coating where the sensitizer has penetrated unevenly, use less Tween
20. Be sure to mix the Tween 20 into the emulsion thoroughly or
it may leave a spot where the over-concentrated Tween 20 penetrated
the paper. You can dilute the Tween with water.
Coating can be done with either a glass rod or a brush. The amount
of sensitizer may vary with the paper being used but it should be
in the 1.5 to 2 ml range for an 8x10 print if you are brush coating.
If you are rod coating, you usually need about 15% less.
The key to success is to get enough but not
too much emulsion on to the paper surface. The use of Tween 20,
will also aid in getting the right coating depth.
Using a coating
The example we will use here is for an 8x10 print on a 11 x 14 sheet
of paper. It is also assumed that you are right handed. Southpaws,
as usual, will have to interpolate.
Prepare a coating area. Obtain a 16 x 16 inch
piece (or larger) of 1/4 inch plate glass. Have the glass shop sand
Using a level, level the glass. A handy trick
is to use a couple of pieces of modeling clay in each corner. It
should be leveled so quite a bit of pressure can be applied and
not squish any clay out of level.
Tape the paper to be coated with a couple of
1-inch strips of masking tape on the two top corners. The paper
will be placed on the glass in "landscape" orientation.
Even portrait orientation prints are coated in the landscape mode.
Lightly mark the 8x10 area to be coated with
pencil marks in the corners.
Measure out your emulsion. It should be approximately
2 ml total. I like to use 1 oz plastic taco sauce cups from restaurant
supply houses, but any small glass or plastic receptacle will do.
Take a clean glass coating rod and place it
about 1 inch to the right hand edge of the area to be coated. The
rod should be pointing from top to bottom of the print.
Hold the rod in your right hand and with your
left hand quickly pour the emulsion from the cup up and down the
length of the rod. It should flow against the rod as your pour.
Now gently but quickly move the rod up and
down about a half-inch to flow the emulsion evenly up and down the
Starting on the right hand side, pull the rod
to just over the left margin of the print. The emulsion will run
up and down the rod due to capillary action.
Now start moving the rod to your left across
the paper covering an area a little larger than than 8x10 with maybe
an inch or so extra on each end. When you get to the left edge lift
the rod slightly off the paper and back down to readjust the emulsion
and then move the rod to the right hand edge.
You will not need much pressure on the rod.
You will continue the back and forth action. In the beginning you
will move at a modest pace. If you were counting you might go: One
.. two .. three .. four.. lift.. down.. reverse direction ..one
.. two .. three.. four and so on. Each count taking about one second
in the beginning
While going back and forth observe the emulsion
line through the clear glass rod. At first it is a running seam
of emulsion but as you progress, it will get thinner. When it becomes
a very thin line, it is time to stop. As the line gets thinner you
will need to go slower and perhaps you will need to add more pressure.
You do not want to break the line. The last pass across the paper
could take 15 seconds or more.
If you have never done this, it may sound exceedingly
complicated, but it is not that difficult. The problem is trying
to describe it in writing. The whole operation is quite intuitive
once you understand two things. Gradually slow down and don't break
the line of emulsion. You might want to practice at first with some
dark coffee (add a little Tween 20 to judge its effects.)
Drying and Humidification
The Ziatype process depends on humidity in the paper to allow the
development to occur during the exposure. The process is quite flexible,
so working practices among printers may vary. Beginning Ziatype
printers should follow this outline at first, and then vary their
practice later to suit their particular printing needs.
One Step Drying
This is the best method to obtain true black. First coat the print
with brush or glass rod. Let the print sit for two or three minutes.
Using a hair drier with a cold air setting, blow dry till the surface
of the paper is just dry. The paper should not crackle when snapped
or bent back and forth gently but quickly. It should sound a little
dead. In no case should the paper be wet enough to transfer any
wetness to a negative. The paper is now ready to print.
Carl Weese has perfected
a method that is almost foolproof.
The basic trick is to run your darkroom at 50-65% relative humidity.
You will need a functioning humidity gage. I need to run a fairly
large humidifier due to the exceptionally dry atmosphere here in
Santa Fe. We are also at 7000 feet altitude, which doesn't help
much either. When I am in a hurry and the humidity is low, I run
hot water in my 16-foot darkroom sink and when Bostick isn't around
to complain, I spray some water on the floor as well. Carl is in
Connecticut and only needs a small electrostatic drugstore humidifier
to get his up to the recommended level. I suspect those in Key West,
Florida may need a de-humidifier to get to the 50-65% level.
Once your darkroom
is set to the right relative humidity range, the process is simple.
Coat your paper.
Let it sit for 2 minutes to soak in. .
Dry for 1 minute under a cool air stream,
A small clip on fan will do nicely. Time will vary depending on
fan and print size. Make your first experiments with a negative
that your life doesn't depend on.
What is important is consistency. Once you get a routine that produces
prints you like, just repeat the humidity and drying times. Everything
else like color control and contrast control will then be chemically
Two Step Drying
This method will produce black to black-brown prints with lithium
First coat with a brush or glass rod and let
sit for a few minutes as in the One Step method. Dry the paper thoroughly
on both sides. To humidify, take the print and move it emulsion
side down about 6 inches over the spout of a humidifier. (A standard
ultrasound "sick room" humidifier works best while the
less expensive hot steamers have a tendency to spit water, which
is annoying and could ruin a negative.) Occasionally turn it over
and humidify the back. Try to get an even coating of the paper with
the steam. An 8x10 piece will take only a minute or two to properly
humidify. A good rule of thumb is to listen to the crackle of the
paper. Snap the paper a little and listen. When starting out it
will sound very alive, as humidity builds up it will sound a little
deader. With this method, it will not sound as dead as with the
One can build a very simple chamber with a cardboard box, or more
elaborate ones with full humidity controls. The choice is determined
by the individual's talents and resources. Several printers have
built a chamber with a large clear plastic clothes storage bag with
the bottom having been cut out for the spout of the humidifier.
Some experimentation will reveal the proper
"soak" time for the print. At 60% humidity, 2 to 3 minutes
soaking in the chamber should be about right. Chamber humidification
can quickly over humidify the paper if left too long. The paper
should still have some snap to it and not be like a limp rag.
A good "split back" printing frame will be necessary in
order to check by inspection the exposing print. Bostick & Sullivan
has their own brand for sale.
Take two pieces of 1 mil Mylar (2 and 3 mil
can be used) that are at least one inch larger than the paper and
sandwich the paper between the two. A paintbrush of the appropriate
size can be used to smooth down the Mylar and to effect cohesion
at the edges to seal it. This will both trap the humidity in the
paper and keep it from drying out during exposure and protect your
negative from any wet spots that may have accidentally developed
on the paper during humidification.
The Mylar is a safety precaution and probably
can be dispensed with. Carl Weese and I have printed hundreds if
not thousands of prints and we have not ruined one negative…well,
Assemble the components in the print frame in this order: glass,
negative, Mylar, paper, Mylar, frame back.
Negatives should have a long density range and can even be longer
than that used for traditional platinum and palladium printing.
A good negative would be one with a Base + fog of 0.2 to a Dmax
of 2.0 or more. Because it can tolerate a higher percentage contrasting
agent in the Solution No. 2, the Ziatype process can print traditional
silver negatives with a range as low as base + fog of 0.2 to a Dmax
of 1.2 or less.
Carl and I have found that the Rollo Pyro developer
produces exquisite negatives for the Ziatype process. A negative
that prints in Ziatype also will print beautifully on Ilford Multigrade
II with no filter! The Rollo Pyro developer was designed for use
in Jobo™ processors but works fine as a tray developer as
well. Starting times for Rollo Pyro for Tri-X is 8 minutes in a
Jobo™ processor. This should be a good starting point for
tray development as well.
Some mythology has developed about the
dangers of pyro. It is true that it is poisonous and should be handled
with care but my reading of the research data is that it is no more
dangerous than Metol™, which is used in most developers.
Use either a standard non-silver UV light bank or sunlight.
The Ziatype is about 2 to 3 stops faster than
traditional developing out palladium printing. Exposure should continue
until the print looks right. It will appear yellow in the highlights
but overall the exposure will be correct.
After exposure, immerse in water and wash in a slow stream for about
Prepare the citric acid clearing bath, one
tablespoon to a quart of warm water. Soak in clearing agent for
5 minutes with occasional agitation.
Wash in clear water for 10 minutes.
Blot with archival photographic blotters and
dry on screens or by hanging on clips.
COLOR AND CONTRAST
The Ziatype will tolerate without graining considerable ammonium
dichromate "Contrast Boost" Solution No. 2. However, be
aware that printing times can increase considerably.
The Ziatype system was designed so that color
and contrast are chemically controlled. Changes in the paper humidity
can affect both color and contrast. The Ziatype worker needs only
to devise a working method that is fairly consistent and produces
coated paper with close to the same humidity level. Once that is
achieved, color and contrast can be easily controlled.
One of the advantages of the Ziatype system is the ability to get
a wide range of colors by simply adding various compounds to the
The Ziatype is a work in progress and has a
multitude of variables. Workers are encouraged to experiment.
A lithium palladium print that has been exposed
and allowed to sit without washing and clearing will progressively
A print made with 50% lithium palladium drops,
25% gold chloride (5%) drops, and 25% sodium tungstate (16%) drops
may produce blue/black split tones.
Grays, blues, and purple tones can be obtained
by replacing any portion of the lithium palladium solution in the
emulsion mix with a 5% gold chloride solution. Colors vary with
paper, humidity level and amount replaced. As more is replaced,
the contrast increases.
Variations in color
can be obtained by mixing brown additives with the gold chloride.
The possibilities are endless and have not all been tested. Individual
printers can develop unique combinations to suit their own needs
Origins of the Ziatype Name
The Ziatype was named for the ancient New Mexico Anasazi pueblo
people’s symbol for the sun. The Zia is the familiar circular
image with 4 sets of 4 rays seen on the flag of New Mexico. It seemed
appropriate as our business is located in New Mexico and I had been
using its sun to make the prints.
Bostick & Sullivan Web Site
Check out the Bostick & Sullivan web site for updated information
on the Ziatype and many other technical tips on handcoated photography.