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Lloyd Godman
Alternative
Photographic Processes - (Hand
made photographic -emulsions and processes)
Processes
- Salted Paper Prints
This
section on salt printing many thanks to Wynn White
Check
out Wynn's
work
A dash
of salt
A description of the salted paper print process with some interesting
variations.
Always be careful when handling chemicals. Read the health and safety
instructions.
Combine hydrochloric acid
and sodium hydroxide and what do you get? That's right, sodium chloride
commonly known as table salt. Salt is one of two key ingredients in
the making of salted paper prints.
The salted paper process
was invented by William Henry Fox Talbot, known as The Father of Modern
Photography, in 1833 while he was on his honey moon. He was the first
to make a silver image on paper. On his first attempts paper coated
with a silver nitrate solution and exposed to light only gave a faint
metallic silver image. He later discovered that by first applying salt
to the paper and then coating it with the silver nitrate solution he
could get a much stronger image. This is basically the same way that
we make salt prints today.
Image above: William Henry
Fox Talbot
Photogenic drawing of a fern
leaf, c.1835-40
Salted paper printing process
Recipe I:
Table Salt Sodium
Chloride 2.0 gm
Distilled Water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled Water to make 100.0 ml
I recommend starting with this recipe since it is the most basic. The
amount of salt can be altered slightly but at three grams per 100 ml
the paper prints a very faint violet unless double coated with silver.
At four grams per 100 ml I could only get a faint violet image. It is
possible to make prints with much lower salt concentrations than the
standard 2%. Substituting ammonium chloride for sodium chloride moves
the print color from sepia towards more of a reddish brown and also
increases print speed slightly. The amount of silver nitrate solution
can be lowered to around 10% (10 grams per 100 ml).
Method
Step 1
Mix up the salting solution. Before coating write the name of the paper
on the back in pencil for future reference and also so that after it
is coated and dried you will be able to tell which side the coating
is on. Smooth, preferably hot press, paper works best. It is important
that the paper not be too porous since the solutions will have a tendency
to sink in too deeply. One paper that I have found to work nicely with
no additional sizing is Rising Stonehenge. Using masking tape, tape
the paper at the corners to a heavy sheet of glass. Measure out an appropriate
amount of salting solution. I use a pipette that I have marked so that
the amount of solution won't vary from print to print. Coat the paper.
I like to use a glass rod for coating.
A detailed description of
glass rod coating can be found at Bostick & Sullivan. http://www.bostick-sullivan.com/newbook/Page_thumbs.htm.
Use a foam brush
or hake (Japanese generic term for brush) if you want prints with painterly
brush marks. Allow the paper to dry. A hair drier at any setting can
be used to speed up the process. Salting can be carried out under bright
light and the salted paper will keep indefinitely.
Step 2
After the salted
paper is dry, under safelight conditions, coat it with the silver nitrate
solution. Salted paper is mainly sensitive to ultraviolet light so exposure
to low level tungsten light will not fog it. Just to make sure that
my paper doesn't get fogged I work under the light of a 7 watt, yellow
light bulb placed one meter above my coating area and another one above
my darkroom sink. Be very careful not to get silver nitrate on your
skin or, more importantly, in your eyes. It could blind you. If you
use brushes you should use a separate brush for each of the two solutions.
I use two separate pipettes and coating rods.
Step 3
Dry the paper in the dark. If you use a hair dryer use the cool setting.
The paper is now ready for printing and should be used right away to
avoid fogging.
Recipe II: Tokyo Bay Water
Tokyo Bay water: 50.0 ml
Distilled water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled water to make 100.0 ml
I collected the bay water in a Suntory whisky bottle that had washed
up on the beach. When I got home I boiled it to kill the plankton. Coating
and drying are the same as in Recipe I. The problem with using sea water
is that it is difficult to judge how much salt there is in the water.
One method of testing for salinity calls for silver nitrate, one of
the main ingredients of the salt print.
I learned that there is,
on average, 35 grams of salt in a liter of sea water and slightly less
in bay water due to fresh water runoff. I mistakenly calculated that
it was a 30~35% solution and mixed my first salting solution one part
bay water to fifteen parts distilled water. Even with this small amount
of salt I was able to get a nice print that was quite pink in color.
After realizing my mistake I made another salting solution mixing it
one to one and got a sepia colored print.
Image above: Rocksurf (Tokyo
Bay Water print).
Note: If you absoulutely
have to try this variation but don't have access to Tokoy bay water,
Wynn will be happy to send you some, just send him the postage... ;-)
Recipe III: Wynn's Favorite
Sodium Chloride 2.0 gm
Potassium Citrate 2.0 gm
Distilled water to make 100.0 ml
Silver Nitrate 12.0 gm
Distilled water to make 50.0 gm
Citric Acid 6.0 gm
Distilled water to make 50.0 ml
Sodium chloride is used in this recipe but ammonium chloride gives results
that are almost the same. The amount of potassium citrate can be lowered
or omitted and sodium citrate can also be used in its place. Citrates
seem to give deeper richer browns.
I mask off my prints to give
a neat border around the image area. With the basic salt recipe I kept
getting slight to moderate fog in the masked area. After adding citric
acid to the silver nitrate solution the fog went away. I strongly advise
masking, at least in the beginning, so that you can see whether or not
your prints are clearing properly.
Contrast Control
The safest and most natural way to gain contrast if you are using a
UV printer is to use sunlight. The boost in contrast is substantial.
A very efficient but more
dangerous method of contrast control utilizes potassium dichromate.
Before using this chemical you should be familiar with its hazards.
An MSDS for potassium dichromate can be found at jtbaker.com/msds/englishhtml/P5719.htm.
A general rule would be never
to let it come in contact with any part of your body or to breath in
any potassium dichromate dust, even in minute quantities.
I have mixed solutions of
potassium dichromate from .5% to 10% and keep them in separately numbered
bottles; each bottle being successively .5% more concentrated. Before
coating I add one drop of an appropriate potassium dichromate solution
to the measured out salting solution. With greater concentrations of
dichromate exposure times become increasingly longer. I generally work
in the .5% to 2% range.
Image above: Potassium Dichromate
Bottles
Sizing
In a good salted paper print the image is sharp, rendering great detail.
If the coating solutions soak too deeply into the paper the image will
be in the paper rather than on the surface thus causing the image to
appear dull and lack detail.
Depending on the paper, I
apply a 1-3% (1-3 grams per 100 ml) gelatin sizing. To prepare the sizing
add the gelatin to 25 ml or so of distilled water at room temperature.
Unflavored gelatin purchased at the grocery store works fine. Let the
gelatin bloom for about 20 minutes and then add the final volume of
water at 40-50 degrees C. Stir the solution gently with a glass stirring
rod. It is now ready to be used.
I pour the solution into
a clean print tray and then immerse the paper in the solution. I lift
the paper from the gelatin solution and let most of the liquid run off
of it back into the tray. I then place the paper, face down, on a piece
of thick plexiglass that is resting at an angle and squeegee it with
a glass coating rod that is larger than the paper. I turn the paper
over and squeegee the surface. I hang the paper to dry on a line that
is stretched above my darkroom sink.
As the solution cools it
becomes very messy and difficult to work with. I regularly pour mine
from the tray back into a pirex cup that sits on a coffee warmer. The
optimal temperature for the solution is around 40-45 degrees C and it
should not be heated to above 54 degrees C. If there is any sizing solution
left over it can be covered and kept in the refrigerator for a few days
to be used later after reheating.
Printing
Negative
Salted paper is categorized as printing-out paper and must be printed
by contact. Due to the self masking nature of P.O.P. a negative with
great contrast is needed for optimal results. Salt prints can render
delicate shadow and highlight detail, perhaps better than any other
printing process. If you have been exposing and developing your film
for conventional silver-gelatin paper you probably don't have a negative
with adequate contrast for a standard salted paper print.
I make enlarged negatives
using the Liam Lawless technique of reverse processing of lith film.
It is economical and not so difficult to learn. A detailed description
of this process is found in the article Less is More by Ed Buffaloe
at Unblinking Eye.
Printing
Frame
You will need a split back printing frame so that you can monitor your
exposures without losing registration between the negative and paper.
I use one that I purchased through Bostick & Sullivan and I am very
happy with it.
For masking I use red construction
paper that is just slightly smaller than the paper that I am printing
on. I cut a rectangular opening just larger than the negative and place
it on the paper. I place the negative inside the rectangle.
Light Source
The sun is the most readily available light source and gives the best
contrast. Drawbacks of using sunlight include variable intensity and
long exposure times. It is quite easy to build a UV printer using black
lights as the light source. Exposures are fast and intensity is constant.
It is also nice to be able to print at night.
Image above: Printing Frame
in UV Printer
Exposure
Salt prints need to be exposed well past the point of looking just right
because they will become much lighter during the processing sequence.
After a little experience you will know when they are right.
Processing
Rinse
After you have determined that the print has received enough exposure
take it out of the printer and rinse the unexposed silver. Most of what
I have read calls for a simple rinse in running water but my tap water
is quite alkaline at about pH 8 and has given me trouble with fog. To
be on the safe side I rinse my prints in five consecutive trays of 1%
citric acid solution for one minute in each tray. I fill four trays
and after I have moved the print to the second tray I dump the first
one, rinse it, and refill it. It now becomes tray number five.
Fixer
After the initial rinse salt prints must be thoroughly fixed. Be sure
to use fresh fixer. I use a 10% solution of sodium thiosulfate (hypo)
adding 2 grams of sodium bicarbonate to each liter of fixer. The sodium
bicarbonate helps to hold back the bleaching that takes place and to
keep the fixer slightly alkaline. I use two trays and fix for three
minutes in each tray. After fixing prints should be immersed in a clearing
agent. I leave my salt prints in clearing agent for three minutes.
Wash
I wash my prints in an archival print washer for one hour and then hang
them on a line above my sink to dry.
Salt Print Reducer (Bleach)
Potassium Ferricyanide .25 gm (one coffee stirrer spoonful)
Potassium Bromide .2 gm (2 ml 10% solution)
Hypo 5.0 gm (10 ml 50% solution)
Water to make 1000.0 ml
Immerse the print in water and then check to make sure that there are
no bubbles on the surface. It is then transferred to the reducer and
agitated until the desired degree of bleaching is achieved. After reduction
prints are treated in a clearing agent and then washed.
Salt Print
Toner Recipes
Toning not only changes the image color of the salted paper print but
also makes it much more permanent. The following toners can all be used
before fixing or after. They all keep well and can be replenished.
Platinum Toner
Water 400.0 ml
Potassium Chloroplatinite (20% sol.) 1.0 ml
Citric Acid 2.5 gm
Sodium Chloride 2.5 gm<
Water to make 500.0 ml
Place the print in the toner and agitate it until the desired tone is
acquired; usually three to ten minutes. If you tone before fixing the
print should be rinsed for at least a minute in running water before
it goes into the fixing bath. This toner gives a warm gray tone.
Palladium Toner
Water 400.0 ml
Sodium Chloropalladite (15% sol.) 2.0 ml
Citric Acid 2.5 gm
Sodium Chloride 2.5 gm
Water to make 500.0 ml
Place the print in the toner and agitate it until the desired tone is
acquired; usually three to ten minutes. If you tone before fixing the
print should be rinsed for at least a minute in running water before
it goes into the fixing bath. This toner gives a warm tone. Palladium
toner has a tendency to lower contrast and also to move the color of
the paper base from white to cream.
Gold/Borax Toner
Warm Water (38 degrees C) 400.0 ml
Borax 3.0 gm
Gold Chloride (1% sol.) 6.0 ml
Water to make 500.0 ml
After mixing the toner wait for one hour before using it. Place the
print in the toner and agitate it until the desired tone is acquired;
usually three to ten minutes. The print can go directly into the fixing
bath if you tone before fixing. This toner gives a slightly warm tone.
Gold/Thiocarbamide
Toner (my favorite):
Gold Chloride (1% sol.) 12.0 ml
Thiourea (1% sol.) 12.0 ml
Tartaric Acid (10% sol.) 12.0 ml
Sodium Chloride 5.0 gm
Distilled Water to make 250.0 ml
Add the thiourea solution to the 12.5 ml of gold chloride solution until
the precipitate that forms is dissolved. The quantity of the thiourea
solution should be slightly more than that of the gold chloride. Add
the tartaric acid to 150 ml of distilled water. Add the gold thiourea
solution to the acid solution and mix thoroughly. Last, add the salt
and top the solution off with water to 250 ml and stir until it is uniform.
The solution requires no
aging; it is ready for use directly after mixing. It tones highlights
and shadows at the same rate so the print tones evenly and can be removed
from the toning bath at any time. It keeps well and resists decomposition
even after moderate use. Tones from plum red to neutral gray can be
achieved with this toner.
In conclusion
Everything that I have written here has been tried and proven by me
personally. I feel that I have only just begun my exploration of the
possibilities of the salted paper process. Salt printing is quite flexible
and offers the practitioner a multitude of creative avenues. None of
the formulas in this report must be followed exactly and I urge you
to experiment and to explore so that you can experience some of the
joys and disappointments that our predecessors must have experienced
back in the 19th century.
Salted Paper Prints
1834-1850s Discovery William Henry Fox Talbot invented the salt paper
print process in 1834. This process was used: - to make prints first
from Talbot's photogenic drawings - from the early 1840s onwards, to
make prints from calotype negatives produced by Talbot and others. -
later, occasionally to make prints from collodion negatives on glass
Process Create the Image 1. Immerse fine writing paper in a weak solution
of common salt (sodium chloride). 2. Blot the paper to dry it. 3. Coat
the paper with a 20% solution of silver nitrate. This creates silver
nitrate crystals. These are deposited within the fibres of the paper;
not held in by gelatin as was the case with later processes. The amount
of silver deposited in the paper was only about one tenth the level
that is found in modern prints. 3. Lay the negative over the paper and
expose to sunlight. Fix the Image 4. After exposure fix the image to
ensure that it remains captured on the paper. Fixing can be achieved
by using: - a concentrated solution of silver nitrate - hyposulphite
of soda ('hypo') as is used today, or - one of the halides such as silver
iodide. The use of sodium hyposulphite (hypo) to fix prints was known
from the early days, but Talbot continued to use his concentrated silver
nitrate (salt) solution. The early photographers in St Andrews also
persisted with salt fixing their prints, and had difficulty achieving
successful results. Later, Talbot changed to using silver bromide to
fix his prints. A more popular fixer, used by others was silver iodide.
Silver chloride and potassium bromide could also be used. Hill &
Adamson experimented with several of these fixing solutions. 5. After
fixing, wash he print thoroughly to remove the fixer and prevent it
subsequently damaging the print. Some photographers washed their prints
for 12 to 24 hours or longer, perhaps using 20 changes of water. Blanquet-
Evrard's Announcement - 1851 The above is a 'printing-out process'.
This is the process that was normally used. However, Louis-Desiré
Blanquet-Evrard, in 1851 announced that it was possible to produce prints
more quickly by developing, fixing and washing, as for a negative. Result
Hill & Adamson's Results The results was a small brown image, which
could be delightful when well printed, though many early photographers
had difficulty making successful salt prints. SALTED PAPER PRINT from
a CALOTYPE NEGATIVE © Sheriff Munro and his daughter by Hill &
Adamson The success of the process, and the amount of detail retained
in the calotype depended on many factors, including the batch of paper
used. Talbot often used Watman's Rag Paper. Turner's Patent Tablotype
paper gave excellent results in the late 1840s and early 1850s. Much
of the paper produced today includes bleaches, or even hypo, and so
is not suitable for making calotype prints. Fading The image was very
delicate and liable to fade. Fading can be reduced by the exclusion
of air. e.g. when two prints have been pressed together in a photographic
album, they tend to show less fading. Many of Talbot's images have faded
badly. Hill & Adamson's images have survived better, apart from
fading around the edges of some. This may be due to the care taken by
Adamson in making the prints - possibly even due to some particular
aspect of Adamson's processing. DO Hill remarked that Adamson "...
thinks he knows some things others do not." Tones in the Print
Tones of salted paper prints can vary from reddish-brown to chestnut
brown; purplish brown if toned with gold chloride for greater permanence;
yellowish brown if faded. They sometimes exhibit a lilac tone. This
is likely to occur in prints fixed with silver chloride, and is due
to incomplete removal of silver by the fixer. They sometimes exhibit
primrose yellow tones. This is likely to occur in iodide-fixed prints,
and is due to silver chloride having been transformed to silver iodide.
Surface of the Print Except for those that hae been glazed or varnished
with a thin coating of albumen (so producing albumenized salt prints),
salt paper prints have a matt surface. The tones are embedded in the
fibres of the paper. Waxed Paper Negatives Waxing of the negative paper
enabled more detail to be retained, and prevented the fibres of the
calotype negative being seen in the final print. In Edinburgh Hill &
Adamson The work of Talbot in Edinburgh, Hill and Adamson and other
early Edinburgh photographers is mentioned on the page describing the
Calotype process. SALTED PAPER PRINT from a CALOTYPE NEGATIVE ©
Sir David Brewster by Hill & Adamson Talbot left a documentary record
of his methods for producing prints. Hill & Adamson did not.
http://www.edinphoto.org.uk/1/1_early_photography_-_processes.htm
Want to learn more? - do a workshop or one on one with Lloyd Godman
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