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Reilly, James M. The Albumen &
Salted Paper Book: The history and practice of photographic
printing, 1840-1895. Light Impressions Corporation.
Rochester, 1980.
Chapter
Two
Working Environment, Equipment and Materials
The printer should be allowed everything of the best quality to
work with, and have a comfortable room to work in.
--Edward L. Wilson, 18811
Work Areas
The best approach to organizing work areas is to follow the plan
adopted by 19th-century portrait galleries--to have two separate
working rooms, a "wet" fabrication area and a "dry" printing area in
which to load printing frames and store equipment away from chemical
contamination. It is preferable but not absolutely necessary that
these two areas be separate rooms, but if they must share the same
room, rigorous cleanliness is required. Certain requirements are
common to both areas. Ideally, they should both be well lit, well
ventilated, and maintained at 18-20°C and 45% relative humidity.
The capacity to eliminate white light from all work areas is also
necessary. Both areas need safelight illumination; for this purpose
yellow "bug-lite" 60-watt incandescent bulbs work perfectly. There
is no need to work in the dim light of safelights required for
modern papers. The level of illumination should be bright enough to
see and work comfortably. In the 19th century, windows of printing
rooms were simply hung with yellow curtains or painted over with
yellow paint.
THE "WET" AREA
The primary purpose of this area is to provide a place for the
coating, drying, and processing of materials. The operations
involved in coating and sensitizing should be carried on in an area
that can tolerate the possibility of spills and stains. Drippings
from papers hung up to dry are inevitable, and somehow silver
nitrate stains always appear on floors and tables despite all
precautions. A basement room is a very practical choice, providing
it can be kept clean and humidity can be controlled. The level of
cleanliness certainly does not have to be that of industrial paper
coating facilities, but ought to be as clean as any well-kept
darkroom.
Generous counter space should be available, and also adequate
storage for chemicals, trays, glassware, and other equipment.
Although a darkroom sink is not necessary, a sink of some kind is
necessary and a darkroom type is helpful. There should also an area
where freshly coated papers may be hung to dry. For safety reasons,
sensitized papers should not be hung where people may pass
underneath them. The floor underneath this
section may be covered with plastic or newspaper to stick to wooden
ones) serve well, and the lines should be strung at an angle of 5 to
7 degrees in order to concentrate runoff at one corner of the sheet.
It is sometimes helpful to accelerate drying of papers with heat; if
the room is small, portable electric heaters will serve the purpose.
Always check to make sure that electrical wiring is adequate
to handle the load created by portable hearers. Each 1250-watt
heater should be placed on a separate circuit and heaters should
never be left unattended.
THE "DRY" AREA, OR PRINTING ROOM
Fig. 3. A printing room, ca. 1875. Printing frames are being
exposed in a window shelf. An ammonia fuming box is shown at
left.
Once the printing papers have been sensitized and dried the
actual operations of printing may begin, and for this purpose an
area is needed that is free from the danger of splashing chemicals
and airborne contamination. Counter space is required, and storage
for printing frames when not in use. Daylight should be excluded
from the printing room altogether, but incandescent white lights and
yellow "bug-lire" safelights are necessary. It is difficult to
evaluate the progress of exposure under yellow light; white lights
may be turned on long enough to make the inspection. Incandescent
white light is preferable to fluorescent light for inspection
purposes because the chances of fogging the paper are lessened. Two
drawers, one for unexposed paper and the other for exposed prints,
are also helpful. If conditions of temperature and relative humidity
are appropriate, then negatives may be conveniently stored in the
printing room as well. The printing room may also double as a print
finishing area, since this operation, too, must be kept away from
chemical contamination.
Equipment
Items of necessary equipment will include the following:
LABORATORY BALANCE
It is necessary to weigh out amounts of chemicals with reasonable
accuracy, but a sophisticated and expensive laboratory balance is
not required. A "student" grade balance with a capacity of 2000 g
and an accuracy to 0.5 g will be satisfactory. A two-pan type of
balance is inexpensive and convenient. Note that throughout this
book the symbol g is used to mean the metric gram, a unit of
weight equal to 15.432 grains.
Fig. 4. A typical laboratory balance of the 1880's.
MEASURING AND MIXING CONTAINERS
For most purposes of measuring and mixing, polyethylene graduated
beakers with handles are the most practical. They are unbreakable
and easily cleaned. A 1000 ml and a 2500 ml model should be enough
for most mixing needs. For measuring small amounts of liquids a 100
ml cylinder graduate with 1 ml graduations will be helpful. A
generous supply of glass or plastic stirring rods is also necessary.
A three gallon plastic or porcelain pail will come in handy if large
amounts of liquids are to be mixed, and the pail may double as a
dishpan for cleaning laboratory glassware. Trays and glassware
should be cleaned with AlconoxTM or
SparkleenTM, detergents specially made for
cleaning laboratory articles.
TRAYS
Trays that have been in use for ordinary photographic procedures
are usually unsatisfactory for albumen and salted paper printing
because of contamination. A good approach is to buy new trays and to
label them for each operation, so that there is one tray reserved
for sensitizing, toning, and fixing, respectively. Porcelain trays
are preferable, as long as they are not chipped in any way. Very
inexpensive porcelain trays may be purchased from restaurant supply
stores. While they may not be in the usual photographic formats--8 x
10, 11 x 14, etc.,--they are still serviceable, and far cheaper than
trays sold for exclusively photographic use. The tray reserved for
the silver solution is especially susceptible
to chemical contamination, and ideally should be made of glass. If
glass is not available, then a new porcelain or plastic tray will
do.
Fig. 5. Glass trays, although breakable, were easily kept clean
and free of contamination. From a 1901 advertisement.
PRINTING FRAMES
Fig. 6. "Anthony's Improved Printing Frame". A closeup view of
the counter device is shown at right.
The printing frame is perhaps the single most important piece of
equipment used in albumen and salted paper printing. The purpose of
the printing frame is to provide a means of keeping the negative in
direct contact with the paper during exposure, and at the same time
allow the paper to be inspected and returned to contact in exact
register with the negative. The basic design of printing frames has
not changed very much since the 1840's; it consists of a wooden
frame with a pane of glass in front, and a hinged back that fits
inside the frame and is held in place by springs. The reason for the
hinged, two-part back is so that one spring may be loosened, half of
the back opened, and the progress of the exposure checked while the
still-closed section holds the negative and print together to
maintain registration. A felt or chamois pad is used between the
paper and the back of the printing frame to evenly distribute the
pressure and insure good contact over the entire print area. The use
of such pads was very common in the 19th-century, but so little
contact printing is done today that most people are unaware of their
benefits. When printing from 8x10 or larger film negatives, pads are
indispensable, especially with the poor quality printing frames
available at the present time.
Printing frames should be at least one "format" larger than the
negative in use--a 5x7 frame for a 4x5
negative, for example,--and they should be kept clean and dust-free.
They should be of sturdy construction, with double-thickness
"picture glass," not ordinary window glass, and have a good-quality
laminated back for strength. Sadly, the printing frames available
from photographic dealers today fall far short of those made in
years past that were intended for tugged professional use. Many
currently-made frames have backs of aptly-named "chipboard," which
will constantly release wood splinters and spoil prints and
negatives unless the utmost care is taken. It is still possible to
find older printing frames made of beautifully finished hardwoods at
antique stores or flea markets, or even from dealers in antique
photographica, but the larger sizes of these are scarce. The older
frames are a joy to use and are often less costly than their painted
plywood descendants.
Many older frames have a counter device on the back. This can
take the form of a notched wheel with incised numbers or may be a
pointer arm that points at embossed numbers; the purpose of these
counters was to keep track of the number of prints made from a given
negative. With many frames and negatives in use at one time it was a
handy accounting system for the quantity of prints made from each
negative.
Paper
Paper suitable for albumen and salted paper printing must be of
the highest standards of purity. Only papers which are
"all-rag"--meaning that they are formed of pure cellulose--are
acceptable. Prior to the 1920's the only way to produce a pure
cellulose paper was to make it from cotton or linen rags, since the
fibers of these plants are composed of cellulose in a pure form.
Papers made from other plant materials, such as wood pulp, straw, or
hemp, contained impurities that reacted with chemicals in sensitized
coatings and speedily led to the destruction of the image. Even in
the absence of a sensitized coating, impurities in such papers
eventually converted to acids, which would cause yellowing and
brittleness. The science of papermaking at the present time does
allow wood pulp to be purified until mostly pure cellulose remains,
and papers are now produced for photographic purposes which have no
cotton or linen content, yet are equal to true "rag" papers in
nearly every respect. Another reason why "all-rag" papers are
necessary is their great strength, especially when wet; ordinary
paper would simply fall to pieces if subjected to the rigors of
coating, sensitizing, and processing. Even lightweight rag
papers--which are preferable because they are easier to manipulate
in floating steps--will not tear in processing.
Fig. 7. Cutting rags for papermaking.
Better grades of paper were made from selected rags hand cut into
small squares on a special inclined knife.
In addition to the composition of the fibers, other criteria for
paper selection are the color and texture of the surface.
Coarse-textured, porous surfaces will tend to absorb the
light-sensitive coatings, and the resultant prints may be flat and
dull. If prints look better by transmitted light than by reflected
light, then the solutions have sunk too deeply into the paper
fibers, and either a pre-sizing step or more viscous coating is
needed. If paper is tinted, the color should not be too strong and
in any case should harmonize with the color of the photographic
image. Paper with a smooth surface and white color is a good
starting point from which to become acquainted with the color and
textural qualities of various light-sensitive coatings and toning
techniques.
Smooth-surfaced papers are the result of a combination of heavy
sizing (sizing is the material added to the paper pulp to bind the
fibers together and create a smooth surface on the sheet) and
rolling between rollers to further flatten and polish the surface.
If a very glossy print is desired, the paper should be as smooth as
possible to begin with. Matte paper may be generated either by
coating a smooth sheet with a matte coating material like starch, or
by coating a porous sheet with a relatively more viscous and smooth
coating.
In the 19th century, obtaining the proper paper for albumen and
salted paper printing was a very difficult problem, especially for
the large-scale production of albumen paper. Two firms emerged in
the 1850's as producers of reliable paper for photographic
use2 and dominated the world market until 1914, when the
press of wartime need forced the development of new production
facilities. These two mills, one in Rives, France, near Grenoble and
the other in Malmedy, Belgium, supplied nearly all of the
photographic rawstock consumed in the 19th century. They possessed
the natural advantage of being located on mineral-free water
supplies, which, together with their experience in the specialized
needs of photographic paper, insured their continued success.
Binder Materials Used in Printing Papers
Many organic materials--proteins mainly but also some
carbohydrates--are useful as binders or vehicles in which to
disperse silver chloride and at the same time confine it to the
print surface. Albumen, gelatin, starches, and whey were all in use
for salted papers before 1855. Of these, albumen was by far the one
most widely used in the 19th century. It is also the only one of the
binders that an experienced eye may identify with reasonable
certainty with just a cursory examination of a print. The following
short descriptions of binder materials does not constitute an
exhaustive list, and it touches only on those properties of the
materials which bear on their photographic use.
ALBUMEN
Albumen for photographic purposes may be taken to mean the clear
white of a hen's egg. Actually many specific proteins can be
identified in egg white, but when used collectively they are
referred to as albumen. Albumen has a specific gravity of 1.040, and
at room temperature it dries to a brittle, transparent mass. Albumen
may currently be obtained as a powder, of which a 15% solution in
water will approximate native egg white, but the powdered albumen is
more costly and less convenient for photographic use than albumen
obtained directly from eggs.
Albumen is insoluble in alcohol, and in fact alcohol will
coagulate albumen, a property that is useful to obtain multiple
coatings of albumen on a single sheet. Albumen is also coagulated by
temperatures above 65°C and by contact with salts of metals. The reason why albumen does not dissolve off the
sheet during processing is because contact with silver nitrate in
the sensitizing bath coagulates it and forms a new insoluble
silver-albumen complex called silver albumenate. This substance
itself is light sensitive and makes an important contribution to
image formation in albumen paper.
Fig. 8. The leghorn chicken, displaying an ideal shape for .
-maximum egg production.
The pH of native egg white is 7.8. Albumen is used in this fresh
alkaline condition only for matte papers, and for these it is always
mixed with starch or other substances. Glossy papers are prepared
with partially decomposed acidic albumen, because in that condition
it creates a glossier surface and more even coating, and has less
tendency to yellow after sensitization. Albumen is never used in the
strictly native condition; before any photographic use may be
contemplated, the egg whites must be beaten to a froth and allowed
to settle back to a liquid state. This beating process denatures the
various proteins--all of which have different viscosities--and
results in a homogeneous liquid which will form an even layer on the
sheet of paper.
GELATIN
Like albumen, gelatin is not a specific substance but a
collection of proteins. Gelatin is obtained by cooking the skins,
tendons, and bones of cattle in a pH controlled vat of water. If the
temperature and pH of the cooking liquor are carefully controlled,
very pure forms of gelatin may be obtained. In cold water, dried
gelatin swells to a viscous mass, which will melt at temperatures
above 32°C. Gelatin is not precipitated by metal salts in the
same way that albumen is, but additions of alum to solutions of
gelatin result in gels that are harder and less permeable. Adding
potassium chrome alum results in gels that are completely insoluble.
Formaldehyde also exerts a hardening effect on gelatin.
Gelatin lends a characteristic reddish color to salted paper
prints. The first salted papers made by Fox Talbot showed this
reddish color, not because Talbot had included gelatin in his
"salting" solution, but because the gelatin was already present on
the paper, put there as a sizing by the paper
manufacturer.
STARCHES
Starch occurs widely in the plant kingdom, and exists as
microscopic white grains that are insoluble in alcohol, ether, and
cold water. When starch is heated in water, the grains burst and a
turbid paste is created. The turbidity and adhesive properties of
starch pastes vary with the origin of the grains. Although many
different kinds of starch may be used for photographic purposes,
certain ones are preferred because the pastes they produce are pure
white, very viscous, odorless, and of low turbidity. Among these the
most important is arrowroot, which comes from the West Indian plant
maranta arundinacea, though tapioca and sago are also useful.
When starch pastes are applied to paper and dried, a layer is formed
that will not swell in water and will withstand the processing
solutions without damage. Starches do not react with silver salts
and have no effect on the reduction of silver chloride. Most salted
papers that use starch as a binder will therefore also have an
"active" organic substance--usually citric acid--as part of the
formula.
RESINS
Resins are noncrystallizable, amorphous substances which are
obtained from plants, notably the sap of softwoods such as pine and
fir. Resins are distinguished from gums by their insolubility in
water. They are soluble in alcohol, ether, etc., and such solutions
are known as lacquers. When mixed with alkalies such as ammonia or
sodium hydroxide, they form foamy solutions known as resin soaps; if
acids are added to resin soaps, the resin is precipitated in an
insoluble form. Resin soaps are also precipitated by contact with
silver nitrate solutions, forming an insoluble white mass that is
moderately light-sensitive.3 The presence of resins has
no effect on the reduction of silver chloride.
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