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Introduction
In this chapter we will cover the fundamentals of the process and
find out how we can safely and effectively set up and make Temperaprints.
By following the guidance in this fundamentals chapter, step by step,
you will without reference to the rest of the book, produce a good Temperaprint.
It will be precise and practical. However we will not go into any more
detail than is necessary, preferring instead to inform you of the basic
major considerations, which underlie the working practices of the process.
We will cover the manufacture of the Temperaprint emulsion, how to coat
that emulsion, the exposure, wash off and final clearing of the residual
dichromate stains ready to lay on further coats. Where possible specialist
techniques will be covered in their relevant chapters and can be considered
once you have achieved an understanding of these basic fundamentals.
Temperaprint Emulsion
The Temperaprint emulsion is a light sensitive compound and as such
needs to be worked in a safe light situation, such as any other photographic
emulsion, but it is nowhere near as sensitive as regular photographic
materials, so the normal darkroom requirement does not apply. Sun and
daylight must be completely excluded. You should work by the light of
an ordinary filament light bulb not stronger than 100 watt at a reasonable
distance and not fluorescent tubes. You will need to see what you are
doing so don't handicap yourself by being to mean with the light, but
don't be unaware of it either. The mixture is light sensitive. The emulsion
itself consists of three major parts, whole egg, sensitizer and colouring
matter. The following descriptions will take you through the sequential
construction of this emulsion.
Before you begin to print, read through the environment sections of the
fundamentals chapter and ensure that you have suitably prepared the environment
and have in place all the tools.
Preparing the Egg
Tools Materials
Three large eggs
Sealable container
Tea strainer preferably stainless steel
500ml Measuring vessel
Break three eggs into a sealable container that is large enough to allow
plenty of room for the egg to splosh about. Once sealed shake the container
vigorously to mix up the egg into a uniform liquid state.
Always use the freshest egg possible. Store bought eggs work fine providing
they are fresh.
A fresh egg will have a strong sac and will form a firm mound. Over time,
the sac weakens, as does the binding strength of its contents.
The type of egg used can also affect binding strength. Fresh eggs from
free-range chickens will produce a stronger binder because of the rich,
viscous yolks.
Though appearing uniform the egg will have small clots, the yoke sack,
speck etc. and possibly pieces of eggshell that have fallen in. So it
will be necessary to remove these. Filter the egg through a fine tea strainer
into the measuring vessel, remove the strainer as soon as the flow has
dropped off and wash. What you will see are the white stingy clots and
yoke sack washing away down the sink.
If this raw egg is not correctly filtered these stringy semi-clotted parts
of the egg will pass into the emulsion stage where they will get up to
all kinds of mischief, on to the roller and coating area and form irregular
lighter patches or blotchiness to appear in the print.
It is sound practice, to make sure that you wash and put up to drain and
dry all the tools [such as in this case the sealable container, measuring
vessel, tea-strainer] at the end of each stage.
To make a Saturated Solution
Tools materials
Safelighting 100watt filament (household bulb)
Clean sink with running water
Glass container with a sealable lid.
Distilled water
Protective Gloves
Ammonium Dichromate powdered chemical,
Dark brown glass storage container
5ml spoon preferably stainless steel
A saturated solution is where, water reaches a point at which it is unable
absorb any more of a dissolvable chemical, and becomes saturated. Once
this condition is reached any further additions of the chemical will not
be absorbed and it will just sit on the bottom of its container until
further water is added. A saturated solution will always be the same,
and is therefore known and constant.
You can use bottled, de-ionised, or still spa water for the purpose. The
best water to use is distilled water. Never use tap water! To this water
is added Ammonium Dichromate, which is the actual sensitizer. It is these
chemicals when mixed with a colloid such as egg. That has the effect of
hardening the colloid in direct proportion to the amount of light that
it receives. Rendering it insoluble or tanning as it is sometimes described.
Making a saturated solution is a very easy task. Work cleanly and keep
the chemistry contained to an area that can be cleaned, and has running
water such as a sink, and wear protective/disposable gloves.
Take a glass container with a sealable lid and add 100ml of pure water.
To this add two heaped spoons of Ammonium Dichromate crystals and close
the container. You will notice that the water turns yellow and that the
crystals are sitting on the bottom, now agitate the container for thirty
seconds. To check your progress let the crystals settle. The fine dust
like particles will have dissolved away first, so what you should see
when it clears is just the larger lump's looking rather like sugar crystals
in water. Once most of the crystals have dissolved, add another heaped
spoon and continue to agitate, checking periodically on your progress.
When you notice that the fine particles remain, as slurry on the bottom,
and no amount of agitation will get them to dissolve, the solution is
now saturated.
Keeping the glass container sealed, wash under running water to remove
any sensitizer that may have escaped or is trapped in the threads of the
lid and clean up the area.
In this saturated state the solution will last for months provided it
is kept from the light in a dark brown glass container To maintain the
saturated solution, add more of the distilled water or Ammonium Dichromate,
always ensuring that a fine slurry of crystals is present on the bottom.
Again make sure that all the containers and tools you have used are washed
up and put to dry
Issues and Concerns
All chemistry can be considered potentially dangerous and therefore should
be treated with respect.
- You should not inhale the
dust
- Use protective or disposable
gloves when mixing the sensitizer
- Remove any splashes on
your skin immediately
STEM
STEM stands for Standard Emulsion Mix, (STEM). It is a mixture primarily
of the whole egg with Ammonium Dichromate, which is our sensitizer. Each
part needs to be prepared separately and then brought together in the
right proportions. It is at this stage of the process that the STEM can
be adjusted for particular working characteristic. Though not complicated
in any way, it should be born in mind that it is
important that the measuring is done accurately for results to be consistent.
Assembling the STEM
Tools materials
Sealable container
500ml Measuring vessel
To complete the STEM, measure out a 100ml of the filtered liquid
egg into a sealable container. Now add 50ml of saturated sensitizer
solution. Seal the container and agitate vigorously for ten to twenty
seconds to ensure that the two liquids are fully mixed. When you open
the jar you will see a frothed up orange liquid .Do not worry about this,
the froth soon settles down. This is the basic STEM mix and is transferred
into a measuring jug.
It is at this stage that various adjustments can be made to the basic
STEM. Other constituent's such as plasticizer's flow enhancer's, other
elements, and colloids can be added to improve performance. When working
the process at an advanced level and is fully explained in the relevant
appendix
Only make up enough standard emulsion for one printmaking session of say
three hours duration. Given time this emulsion will spoil due to dark
reaction effects that are similar to the way that milk goes sour with
time and temperature. Therefore the STEM must be discarded at the end
of each print session even you have made up a large quantity. IT CANNOT
be stored for later use.
Again make sure that all the containers and tools you have used are washed
up and put to dry.
Colouring the STEM Solution
The colouring of the STEM can be done in a number of ways using a
variety of colouring materials. In this initial method, we will use a
painting medium to colour the STEM solution, {which we now call the Temperaprint
Emulsion.} artist quality acrylic paint is employed. There are many different
brands and all will work; though some may not be as strong in pigmentation
as others may. We use an acrylic paint known as Liquitex in little bottles
and jars. A highly concentrated colourant which is added in a fixed proportion
by volume to the Temperaprint Emulsion.
You may also use raw powdered pigments, or watercolours in which case
you may wish to add acrylic when assembling the Temperaprint Emulsion.
Omission of this element is not a catastrophe. It only means that the
resultant image that you get after you have exposed and washed off will
be a little softer both in edge and in its physical properties. Dyes are
not normally suitable for use, despite the fact that they are water based
and will work. Almost all dyes are fugitive and therefore of no real value
in a system that has great archival potential, such as Temperaprint
Tools Materials
1/2 inch Brush
STEM solution
Bottle/jar of Acrylic Paint [Liquitex]
5ml Measuring Spoon preferably stainless steel /or a syringe without needle
Small Pallet Knife
Take the 5ml spoon and squeeze out or pour enough paint to make a level
spoon full of paint, if necessary use the pallet knife to ensure accuracy.
A very accurate alternative method is to use a 5ml plastic syringe.
Now use the brush to move the paint into a suitable container or the paint
tray. Add 5 ml of the STEM solution and begin to work the paint and STEM
solution into each other until they are thoroughly uniform and mixed.
Now add a further 5-ml and again work them together. The important issue
is to ensure as even dispersion as possible, and not to end up with clumps
of pure paint sitting in the bottom of the container or paint tray. Initially
this means working the paint from it original stiff consistency to a liquid
through a series of additions. As this progresses it will get easier to
mix together as the mix becomes more and more fluid.
There can be few hard and fast rules to the correct amount of colorant
to STEM solution as the variables in the supply are just too vast. Experience
and getting to know your materials is in practice the only sure way of
knowing absolutely.
It is important to remember that there are two ways to change colour saturation
or tonal density. One is to increase or decrease the amount of pigment
in the mix. Or secondly to print a number identical coats one on top of
the other in a multiple layer approach. In practice you will tend to use
a mixture of both these methods. However it is noticeable that once the
ratio drops below five parts STEM solution to one part paint the working
characteristics start to radically change. Coats will become heavy, exposure
time will be significantly increased and the contrast will become excessive
until eventually you are unable to gain a good even coat or exposure.
The following provides a general guide to the limitations of how much
colourant it is possible to load into a coat: -
Use one level spoonful of acrylic paint as a standard unit of measure
i.e. 5 ml: -
Chromatically Spoons of Emulsion
Strong Four
Medium [normal] Six
Thin Eight
Glaze Twelve
It is very important to measure these quantities carefully, and consistently,
What has to understand, is that this coloured Temperaprint emulsion. Is
not just some messy paint, but in fact a precise photo-sensitive emulsion.
Again make sure that all the containers and tools you have used are washed
up and put to dry
Coating
Introduction
No coating system is without its problems; in fact the main reason
that the photographic manufacturers gained dominance historically is that
they could successfully coat photographic materials to a high level of
perfection, by the application of precise mechanical factory technique
The principle custom hand coating methods can be summarised as follows:
-
Airbrush,
Brushing hair/foam,
Buffing,
Dip or float on methods,
Foam roller systems,
Glass rod
K/Graber bar,
At the moment our favoured coating tool is the foam roller. Many years
have been spent refining the technique to get the exact balance in the
egg emulsion to print onto a sheet of Yupo/substrate. The foam roller
has one defect when used on a smooth non-absorbent substrate such as Yupo
[laminated polypropylene] it gives a pronounced texture. These footprints
of the foam will normally need two or three coatings to disappear and
give a smooth full-bodied colour. This is the system that will be explained
and used through out this book
What has to be born in mind that this process works best in a multiple
layer manner! Several layers often go the make a single coat and a number
of coatings go to make the final image. So the foam footprint will tend
to disappear quite rapidly of its own accord as printmaking progresses.
The substrate.
Choice
The relationship between the emulsion or paint and the surface quality
of the substrate onto which it will be laid is extremely complex. They
both need to be matched very carefully. Rather like a hand snugly fitting
into a glove.
For instance ideally we would like in the School Temperaprint to employ
watercolour paper, with its beautiful textural surface. However this material
has a number of defects that do not favour its use with our process. It
needs to be very heavily sized to work efficiently. This heavy sizing
destroys the very surface texture that is its main attraction.
The problem lies with the absorbent
nature of the material. This is a
required characteristic for watercolour paper as easy staining is part
and
parcel of the watercolour painting technique.
However the unexposed
soluble egg emulsion has to be removed in our process which is part and
parcel of the processing cycle. The egg emulsion is far to adhesive to
be used in this manner on unsized watercolour paper. The soluble non-image
would just not come out of the paper fibre, resulting in massive pigment
stain.
Secondly the watercolour paper is inherently unstable from a dimensional
point of view.
It stretches and shrinks during the processing cycle. Even when dry it
will still change it shape in response to relative humidity and temperature
change a characteristic that makes fine registration difficult to achieve.
As the process is by its very nature a multiple coat method of printmaking.
The final image is constructed of a number of tonal and/or colour coatings,
each in exact register; it is difficult, if not impossible, to achieve
this aim, with normal untreated watercolour paper.
We have tried many differing substrates and found that with suitable
Sizing or preparation, most, can be made to work with the egg emulsion.
These considerations are further discussed in the advanced section of
the book.
Ideal Base
We have found that an impervious base seems to work best. It facilitates
a stain free surface, and allows for an accurate system of registration.
Thus in one stroke solving the problems, inherent in other processes.
We mainly use a polypropylene plastic paper known as Synteape
In the UK and in the States the product is called Kimdura.
However it is manufactured by the Oji-Yuka Synthetic Paper of Japan and
is called Yupo and can be sourced through: --
http://www.yupo.com/welcome.html
Please find further information in the appendix section
Alternative substrates
This does not mean that there are no alternatives to this excellent product.
Semi-matt RC photopaper can also be employed if the sliver gelatine emulsion
is physically removed with strong domestic bleach. Standard watercolour
paper works if it is strongly sized. We have found that a 10% to 12% solution
of gelatine to be effective. Or two neat coats of Liquatex matte medium.
This changes the quality of the watercolour paper surface to a pleasant
sheen.
Other substrates such as wood, stone, metal, fabric and ceramics will
be dealt with in the advanced section of the book. The virtue of this
process is the ease with which it will happily coat onto a great variety
of substrate surfaces.
The Environment
Tools Materials
Safelighting 100 watt filament (household bulb)
Clean working area
Glass sheets twice the size of the piece of paper.
Piece of Synteape/Kimdura/Yupo larger than the print size
Masking Tape
Paint tray 8-x 4 inch
Foam Roller 4inch
Coloured Temperaprint Emulsion
Paint brush 1/2inch
Kitchen Paper towel
Hairdryer
The Temperaprint emulsion is a light sensitive compound and as such needs
to be worked in a safe light situation, such as any other photographic
emulsion, but it is nowhere near as sensitive as regular photographic
materials, so the normal darkroom requirement does not apply. Sun and
daylight must be completely excluded. You should work by the light of
an ordinary filament light bulb not stronger than 100 watt at a reasonable
distance and keep any fluorescent tubes turned off. You will need to see
what you are doing so don't handicap yourself by being too mean with the
light, but don't be unaware of it either. The mixture is light sensitive.
The working environment must be clean and as free of clutter and dust
free as is practically possible. It is essential that the work surfaces
are kept squeaky clean from commencement to conclusion of the printmaking.
The Temperaprint emulsion will readily pick up any dust, hair, or other
debris in its close proximity.
Coating the Emulsion
Take a sheet of glass; place onto a clean work surface. Attach a piece
of Yupo/substrate to this glass, with masking tape applied to the diagonal
corners. Ideally the sheet of glass should be at least twice the size
of the piece of paper.
You should ensure that your paper has a sufficient border around the actual
print area to allow plenty of room for you to stay on the paper during
the roll coating. This is good practice as it means that you are keeping
the coating environment clean because all unwanted emulsion will be on
the paper surface, not on the glass, and therefore will conveniently wash
away during the print development stage.
Take a four-inch acrylic foam paint roller, and a small paint tray, the
sort that you can buy for using with gloss paint. This tray holds a convenient
amount of the emulsion, as a minimum say 25ml which will be enough to
lay up to 5 coats, and also provides a ribbed palette which can be employed
to contain and control the foam roller. Pour a working amount of Temperaprint
emulsion into this tray. Stir the emulsion with a small brush to ensure
that it is completely smooth and homogenous. Place the roller in the tray,
charge up until the roller has absorbed a "generous" amount
of the mix, then roll out vigorously onto the ribbed palette followed
by clean newsprint until it reaches a conditioned state, neither too wet
nor too dry just damp.
A convenient way to control the amount of the mixture in the roller for
subsequent coating is to paint the mixture on to the ribbed part of the
paint tray and then reload the roller from there. The mixture will get
caught on the ribs of the tray and the amount that is loaded on to the
roller can be quite accurately controlled by this method. This way you
get to know to how much of the mixture you need to replenish the roller
to keep it in the ideal coating condition.
When you begin to coat using the roller, roll in one direction only, not
backwards and forwards. Roll from east to west, then when you reach the
west, lift up the roller and start from the east again. Repeat over and
over again; roll north to south, east to west, change direction from time
to time. This action will seem a bit strange at first but you will soon
get the knack and it is key to getting an even coat.
Try to keep your coating to a defined area, and not just all over the
place, Work to an area larger than the desired print size but inside the
paper dimensions. Throughout the coating, roll the coat methodically so
that all parts of the area get equal treatment from the roller, not just
the middle.
Start to roll down hard onto the substrate then slowly lighten the pressure
until you are only just supporting the handle. When you begin to coat
you should be firm and apply as much pressure as needed to gain the initial
evenness and define your coating area. By the time you are coming to the
end of the coating procedure. The only pressure should be the weight of
the roller handle resting in your hand. Take your time. Let the coat just
relax onto the substrate.
By the time you are coming to the end of the coating the roller should
be moving much faster, as if you were just lightly polishing the surface.
Directly the coat looks even, stop rolling. If all has gone well, you
will end up with a smooth eggshell like finish that will expose well.
Issues and Problems
Beware of handling the Yupo/substrate too much; wash your hands first
so that you do not transfer any grease from your hands to the substrate.
If grease does get on to the Yupo/substrate when you come to lay your
first coat you will get clearly defined fingerprints and patches where
the coat will refuse to take. This can be repaired, by scrubbing the offending
spot with the roller until the coating mixture is no longer repelled by
the substrate. In the long term this is not really a problem as it rarely
persists to the second coat, However it maybe an indication that things
could be more tightly controlled.
Sometimes beginners experience problems with their first coat that appears
blotchy. This is due to the fineness of the surface and the thinness of
the coating and is normal
In this respect the viscosity of the mixture is critical. If it is too
wet you get bubbles that will denigrate into big blotches and if the coat
is too viscous you get little white specks that also give similar unevenness
problems. To solve the former, deplete the roller on a paper kitchen towel
or clean news print paper. Then pass the hot hair dryer over the coat
a few times to stiffen up the coat, and re-roll. To solve the latter throw
away the mix, remake and roll over again. Do not try and let down the
mixture by adding fresh emulsion
As part of the process you will get a pronounced texture on the first
coat. This is the footprint of the foam roller, which will disappear with
subsequent coating. To obtain a texture free coat, first time is very
difficult. So multiple coating is essential. However in practice this
does not pose a problem, as the coats dry very quickly. The process of
building up the image in this manner is very satisfying it puts you in
charge. Not the process, this is one of the great joys of Temperaprint.
Another problem associated with rolling technique is when you get bars
of lighter density appearing in your coat. These bars can be horizontal
or vertical to the direction of the roller. The cause is going outside
your defined coating area compounded by not rolling in one direction in
the early stages. You are allowing the roller to go off the coating area
and onto the uncoated surfaces. This has a direct effect on the roller
as these surfaces now take some of the emulsion from the roller, which
in turn takes it from the part of the coat you want, i.e. from within
the print area. You will notice that the distance between the bars is
the same as the circumference of the roller, which is a sure indication
that this is the problem.
What upsets and effects the students at the School of Temperaprint
are minor imperfections in the preliminary coats coursed by, dust, bits
of hair, and other debris. One of the major causes that has contributed
to this problem has been what the students are themselves wearing, where
fibres from their own clothing can get on to the coating surface. Awareness
of this problem and a clean working environment will certainly substantially
alleviate, if not completely eliminate these problems.
However it must be born in mind that the process is self-healing. As the
multiple coating proceeds, students find that these defects magically
disappear as the further coats heal the perceived defect until it is no
longer noticeable in the print. That perceived defect just seems so much
more important when it is the only mark on the paper, in the first coat!
Drying
Once you have finished laying the coat you will need to dry it prior
to exposure. To do this, apply a stream of warm air over the surface at
the finish of the coating process. This is most conveniently achieved
using a hair dryer. When you come to this part do not hold the hair dryer
over a single spot, keep it moving. If heat is applied to a single spot
you run the risk of heat fogging which needless to say is something that
could ruin a print. Keep the hair dryer moving at all times and at least
nine inches away.
The Yupo/substrate has no fibre to hold moisture so that the only moisture
present is in the actual thin emulsion layer that you have applied. It
will only take a few moments, at most a minute, for this coat to dry.
You can tell when dry by the surface sheen, which turns to an eggshell
matt appearance. To test if the coat is actually dry, turn the hair dryer
on to your free hand to drive off any moisture and then lightly run your
hand round the boarders of your print. That way if it is still tacky you
have not disturbed the main part of the coat that you want to keep. Once
the coat is dry you are ready to make the exposure. Remember the coating
is much more light sensitive when dry. It is a good idea to have a separate
clean workspace dedicated for this purpose. Remember DON'T OVERDRY. Otherwise
a heat fogging will spoil the print.
Exposure
Contact printmaking
NEED
As previously stated, Temperaprint is by its nature very insensitive to
light. Herein lies both the strength and weakness of the process.
Contact printing is the only feasible method. Although there are heroes
who spend hours printing by projection in our opinion, life is just to
short to travel down that path. However they're many advantages to contact
printing .The method is mechanically faster than most the projection technique.
It is possible to print several negatives at the same time, and contact
exposure once assessed, will tend to remain constant.
The
main disadvantage is that to make a reasonable sized print, a negative
of the same size is also needed, and as most of contemporary photographic
image making is centred around small format negatives. Some form of enlarged
duplication will needed
LARGE FORMAT
The prime requisite will be a large format negative that is the same size
as the resultant print. This aim can be achieved in a number of ways, as
the Chinese say there are many paths to heaven not just one.
We at the School of Temperaprint now concentrate on the production of positive
digital files that we then enhance electronically, and output as printers
in either negative or positive separations via the computer and print onto
inkjet film. There is a whole chapter devoted to the production of these
printers later on in the book.
Alternative non-digital methods are also possible and are described in the
technical appendix, for those not conversant with or sympathetic too digital
imaging and control.
.
CONTACT PRINT MAKING
Registration
Need
At the heart of any multiple printing lies the problem of registration
Temperaprint is no different, fortunately our yupo/substrate is dimensionally
stable so half the problem is solved.
Methods
There are many methods of registration that are used in printmaking and
industry. The most common and reliable is the pin register system. This
is a method where the printers are punched with a series of holes that are
in the same place on each of the printers. The paper that you are going
to print onto is also punched and the printers are attached using special
pins that fit the holes perfectly. The joy of this is that the pins will
ensure that the printers always go back in exactly the same place each time
with out the need to visually line them up, as all the registration is carried
out in the initial punching phase.
The problem with this is that these systems are professional and can be
prohibitively expensive. An inexpensive version of this system can be constructed
using a four-hole office punch that is a fraction of the cost of the professional
versions. Unfortunately these punches are not standard in the size of the
hole that they produce and there are no pins on the market to cater for
them. A way that has been found to deal with this problem is to use double-sided
tape and stick two or three layers of Yupo/substrate together with a further
strip of the double-sided tape on one side. These pieces of layered yupo/substrate
are then punched to produce round punched pieces, these punched round pieces
are then attached to a further slightly larger piece, say about three-quarters
of an inch or two centimetres in diameter. This can produce a cheap and
relatively easy way of solving the problem Though not completely perfect
you can make many of these home made pins, so that if they fail, as some
will, it will not matter as you will have many more as spares. A bonus if
you have a problem with miss-laying things in a working studio. Some stick
on rubber or plastic tiles can also be used in a similar manner.
Contact Frames
For a contact frame there are many that are supplied from photographic
manufactures that are perfect for the job. The best type of contact frame
is a vacuum frame where the air is removed using a pump. This results in
an even contact across the whole print area and ensures that all the detail
that is in the printer has a chance to be exposed accurately. Again the
problem is that this is a professional piece of equipment an as such commands
a professional price.
A simple and easy type of frame to make consists of at least four strong
clips, a sheet of glass, and a piece of board cut to the same size as the
glass and some thin foam. Make a sandwich of the board, foam, yupo/substrate
printer and place the glass on top. Now put the clips around the edges and
they should squeeze the glass and the board together, thereby giving you
the contact you need. This is a very rudimentary way of achieving a form
of contact frame.
A more precise method is to construct a pneumatic version known as the litestar
frame as explained in the advanced chapters
Ultra Violet light Sources
Now that you have your coated paper and printer prepared, it is time
to expose it to a light source rich in ultra Violet radiation. A number
of light sources are employable, but most are too weak for this process.
A cheap and convenient source is a sun bed, particularly the small facial
or half size torso type that can be purchased at quite reasonable prices.
It is important to remember that ultra Violet light is a harmful form of
radiation and as such should be contained even if it is a sun bed which
has been designed for tanning skin. The other source of useful light, which
is readily available, is direct sunlight. This can be used, but you will
have to deal with the vagaries of the weather and the time of day. A further
source is a plate maker or silk screen lamp such as is used in industry.
These sources can be very dangerous and you should always confer with the
suppliers on its containment and use.
Of all the sources the simplest and most convenient is the sunbed. You should
be able to purchase this through mail order, or if you are living in the
more northerly climates you may find one in a local store or second hand
shop. The good thing about sunbeds is that they are consistent, repeatable
and can be used with the flick of a switch; a major consideration in a multi-coat
system such as Temperaprint.
To use a sunbed place it face down on supports at each end leaving a gap
underneath for the contact frame to be slid in and out. You can place a
piece of fabric along the edge of the gap to contain the light but do not
cover any heat vents. Exposure should be made at a distance of three to
six inches. If the coating has been carried out correctly. The time exposure
should be in the order of three to five minutes; you will need to test this
for yourself. Which is only a case of making a series of controlled test
exposures to find an optimum time. Darker colours may require a slight increase
in exposure while thinner lighter coats may require slightly less. Familiarisation
with the process will come after making many coatings, and you will in time
be able to see how to make these slight adjustments instinctively.
Wash off Environment
Tools
Sink with running water
Paint pad
Washing-up liquid
Sponge
Small brush
Two photographic flat bottomed dishes, one with a cover
1% sulphuric acid
Glass sheet
Plastic or rubber apron
Protective gloves
Tongs
Eye shields
Ensure that the washing off area has everything in place. There should be
running water, preferably with a hose so that you can direct the water where
you want it. Place in or next to the wash area a bowl with water, containing
a "squirt" of washing-up liquid, in which you can place the paint
pad, brushes and sponge. The glass sheet is to lay the print on during the
development of the coat. It is important that the surface you use for the
wash off is flat and not uneven because when you remove the unwanted portions
of the coat, any irregularities in that surface will result in uneven development.
Depending on your own individual circumstances and preferences you may find
it more comfortable to work in an upright position in which case ensure
that the glass sheet is propped up at a suitable angle inside the wash area
and is not liable to slip. You may find that you prefer to work flat and
have the room to lay the sheet down in the wash area. The choice is not
a critical one but should be made according to comfort and ease. This is
a multi-coat system and you will return to this area time and time again.
There will need to be a provision for the 1% sulphuric acid clearing bath.
This bath at the specified dilution is not dangerous. However it is sensible
to place in a position, that easily disposed of when finished with. Ideally
this should be either in the washing area so that splashes and drips are
contained and easily washed away, or directly adjacent to it so as there
is minimal handling of it in when in use.
The function of this bath is to remove the residual dichromate stain, which
if not removed, will degrade the colours of the print giving them a orange
brown cast, in monochrome this is of no matter, but in fine colour work
it is essential to remove this troublesome caste.
Developing the Coat
Now that you have prepared the area and completed the exposure the next
phase is to remove those parts of the image that have received no exposure.
After you have removed the print from the exposure unit and taken off the
printer, place the print in a tray of water to remove the now unwanted sensitizer.
This soaking phase will still need to be carried out under subdued lighting.
You will notice that the water turns yellow.
This is the Ammonium Dichromate being released from the coating and dissolving
into the water. The importance of this is that the coating layer will no
longer be sensitive to light. This means that once it has had a one minute
soak you can take the print out into a full light situation to complete
the washing phase of the print without any danger to the print
Place the print on the glass sheet and wash with running water to remove
any sensitizer that remains. Take the paint pad and place it flat to the
surface of the print and in a gentile circular motion begin to remove those
portions that are still soluble. As you are doing this, do not press, let
the pad glide over the surface of the print by is own weight do not press
down In this way the pad is very gentile and will produce an even development
if done uniformly.
Work across the whole image area in a methodical manner so that all areas
get equal treatment. From time to time play the water across the surface
so that you can see any area's that have been missed and are not there for
being fully developed. Wash some areas a little less if you want to retain
more of the coat or a little harder if you wish to retain less. Be careful
not to lift the pad on to an edge or corner, this will result in a more
abrasive effect on the coat and will produce an uneven development.
A brush can be used creatively to remove coating in precise area's if required.
. It will be more abrasive than the pad. Having the benefit that you can
tackle individual elements of the image in greater detail giving a more
painterly approach to the manipulation of the image than just using the
pad alone.
A sponge can also be used to remove the coating gently instead of the pad.
Being able to tackle more specific areas. Though not as precise as the use
of the brush it does allow you to scumble the coat in a similar manner as
painters treat a glaze coat, also the application of a small amount of cream
abrasive can be effective. However do not use hash powder type such as Vim.
What is needed is a gentle cream abrasive the type that is used to clean
plastic baths. With these abrasives it is possible to obtain very subtle
graduations of colour and tone.
Clearing Bath
The clearing bath is used to remove the residual dichromate stain that
is left after the print has been developed. The bath consists of a dilute
solution of Sulphuric acid i.e. 1% great care must be taken when this is
initially made up further information will be supplied in the health and
safety section later in this book.
Once you have completed the wash off phase to your satisfaction place the
print into the bath. A yellow tint will become apparent within the bath;
this is the residual stain being removed. The clearing will only take about
a minuet to complete. This stage does not need to be carried out after every
coat and can be either left to the end of the printing, or done at any chosen
point when you wish to check for colour balance.
With monochromatic images using just earth colours you may omit this stage
if you wish, as the stain is a compatible colour so the clearing will predominantly
have a lightening, rather than a chromatic, effect.
Once the print has cleared remove it from the bath and wash.
Final wash
Once cleared the print needs a final wash to get rid of any residual
clearing bath that may interfere with further printmaking.
Dry
Now dry the print keeping the hair-dryer moving at all times, or just
hang it up to dry.
The Synteape/Kimdura/Yupo has no paper fibre so it will dry quite quickly.
You may blot the surface to remove the bulk of the water using J cloths
or other similar non-fibrous material but be careful the surface emulsion
is quite delicate until it has fully dried.
Conclusion
When you have reached this point you are ready to re-coat the print.
Further colour layers will increase the richness of the print but you must
be aware that if you continue to coat beyond a certain point, the print
will begin to darken. Artist colours, in common with all paints work by
the subtraction of light, so further coats will have the effect of taking
more of the reflected light away. Again this is a matter of experience and
cannot be prescribed in advance.
You are now ready to return to the coating stage. The coat that you have
printed is now quite firmly attached to the substrate and will not be removed
by further coating.
Happy printmaking Alex & Pete
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