is a method that is widely used, particularly for printing ink onto fabrics.
In screen printing, a 'mask' is created of a fine mesh material that is
called a screen. Usually the screen is a sheet of polyester cloth. Designs
are created by masking off certain areas of the screen while leaving other
areas open, when you apply ink to the screen, the open parts allow the
ink to go through, and it is deposited onto whatever you put under the
screen. The mask is applied by various methods, but it is commonly made
with a light-sensitive photo emulsion.
While silk screening has been used in enameling, its application has
been limited to the use of fine, liquid enamels. This is because the screens
used to print enamels are the same as those used for printing with ink,
and are very fine. Using liquid enamels makes for several problems. One
problem is that you get thin coverage by the enamel. This is because you
can only get so much liquid enamel onto a surface before it runs or smears.
A second problem is that printing multiple colors, using multiple screens,
can be difficult. Printing the first color onto a surface is no problem.
However, when the screen for a second color is brought into contact with
the surface, the second screen can smear the first color, and you have
all the makings of a mess.
I have worked out a way to use screen printing methods so as to 'print'
on metal, using dry enamels. It is based on using screens made out of
material that is coarse enough to let dry enamel go through it. Designs
can be masked into the screens using photo emulsion. Using this method,
one can apply dry enamels, and have good spatial control over where the
enamel goes. Because the enamel is dry and doesn't stick to the screens,
it is possible to print many colors, using a separate screen for each
color. Therefore, this method allows for using many screens to make elaborate,
multicolored designs. Of interest to the impatient enamelist, is that
it is possible to apply many separate colors, creating a complicated design,
and to fire the resulting piece just once. Figure 1 is an example of a
clock dial that was created using this method. The design was made using
a computer drawing program. Each color in the design was printed onto
a separate transparency using a laser printer. Each transparency was used
to make a screen, using a photo emulsion process. The resulting 10 screens
were used to 'print' the enamels onto the plate. It was fired once. In
this article I describe the steps used in this process.
Step 1: Create the Artwork
I assume that generating the artwork will not be a problem for readers
of Glass on Metal, nonetheless, here are some guidelines. Create your
design in black, on a transparent material. Examples of transparent materials:
glass, plastic sheets. Whatever part of your design you want to be covered
with enamel, draw as black. Examples of suitable formats: draw on your
glass or plastic sheets using a black marking pen; another method is to
paste black paper cutouts on glass. Having poor artistic skills, I use
a drawing program on my personal computer, and I print my drawings as
black, on clear acetate sheets, using a laser printer.
A simple example is shown in Figure 2 (left). The word 'Wow!' was drawn
in red, and given a white shadow. The red and white parts of the drawing
are separated (Figure 2, right) so that they can be printed out separately.
The red part of the drawing is printed on a plastic sheet as shown in
Irrespective of how you create your drawing, there are some important
guidelines to follow:
Drawing Tip #1: Avoid fine lines in your drawing. How thin a line you
can print depends on how fine the screen material is. You have to experiment
to see just how thin a line or how small an area you can successfully
print. Note: it is possible to create fine lines using another method;
this is illustrated at the end of the article.
Drawing Tip #2: Avoid half tones (i.e. gray areas) in your drawing.
They will never work.
Drawing Tip #3: If you want to do multi color printing, you have to
do a color separation, as shown in Figure 2. Each color that you want
to print has to be printed onto a separate transparency. I do this by
printing each color as black, onto a separate acetate sheet, using my
laserjet. Be sure to keep all the sheets in registration.
Step 2: Make the Screen(s)
A. Material. The screen material that I use is a 62 mesh polyester.
The holes in this mesh are (according to the manufacturer) 0.0098 inches
B. Mount the Screen in a Frame. The idea is to stretch the mesh over
some square frame. You can use a small wooden canvas stretcher, and staple
the mesh to it. The frames that you will see in the accompanying Figures,
I made from aluminum window screen frame material. The mesh was mounted
in them much as you would mount window screen material.
Step 3: Transfer the Design to the Screen using
There are three steps here. The underlying principle is that the photo
emulsion is water soluble until it is exposed to light. When it is exposed
to light, it hardens and becomes insoluble in water.
A. Apply Photo Emulsion to the Screen.
I use a standard silk screen photo emulsion kit, from an art supply
store. Follow the instructions in the kit. Mix up the emulsion and spread
it on the screen. I prefer to spread it on with a credit card, as shown
in Figure 4. The goal is to get an even layer of emulsion - no drips,
no holes, and no air bubbles. Then dry the screen. Aiming a fan at it
will expedite the process.
B. Transfer the Artwork to the Screen.
I use a light box for this step. You can see the layout of my light
box in Figure 6. It is a set of four ultraviolet fluorescent bulbs (15
watts) mounted on the bottom of a plywood box that has a glass cover on
the top. I put the artwork on the glass, and then put the screen over
the artwork. When the lights are turned on, the clear part of the drawing
lets light through to those parts of the
screen, and in those places the emulsion hardens. This is demonstrated
in Figure 5, which shows the screen (green) over the drawing (Wow!), and
the lights on. The light will harden the emulsion in all of the screen
except for where the letters are. In contrast (pun intended) the parts
of the screen under the black letters are shielded from the light so that
they remain water soluble. Note: The process of exposure is actually best
done as shown in Figure 6. Cover the back of the screen with black cloth,
then a piece of foam, and hold the whole thing down with a weight (here,
a paint can).
C. Wash Out the Design.
When the exposure is complete, follow the directions in the emulsion
kit, to wash the screen. This is done in Figure 7 with a spray of water.
As you can see, the letters (Wow!) that were under the black parts of
the drawing have washed out the screen. Figure 8 shows what the finished
screen looks like. Dry the screen, and you are ready to go.
Step 4: Print
The basic idea here is to put the screen over a metal plate, and sift
or brush the enamel through it. In Figure 9, a red enamel is being brushed
through the screen. The resulting application of red enamel is shown in
Figure 10. The finished product, after applying white enamel through a
second screen, and after firing, is shown in Figure 11.
Step 5: Cleanup When you are finished with a screen or set of screens, they (the screens)
can be easily cleaned out and made ready for another design. The instructions
with the photo emulsion kit describe it all. Uses of the Method: The use of this technique should be readily apparent to most readers.
It allows you to create almost any design, and to apply enamel with much
greater precision than can be achieved using stencils and the like. The
method should be popular with those involved in production because of
the ability to make multiple copies of a design.
For me, the big pluses come from the ability to redo sections of your
work that you might not like. If you are unhappy with the way something
looks after firing, you can take the screen and use it to cover the offending
area with another color. Thus you can effectively overpaint, and cover
up all your mistakes. Also, don't forget how wonderful it would be to
be able to create elaborate works while firing just once. The niceties
of 'overpainting' notwithstanding, I am impatient enough to consider it
a failure if I have to fire a piece more than once.
In addition to the above, spatial control over the placing of enamel
makes it possible to use this method to achieve some unique and interesting
effects, some of which are described below.
A. Overprinting Enamels: Breakthrough. Many layers of dry enamel can
be applied to the same part of the design. For example, print a region
with an opaque enamel. Then clean off the screen and apply a transparent
enamel directly on top of the opaque. When this is fired at high temperature,
it results in a region of controlled breakthrough, as shown in Figure
B. Overprinting Enamels: Fine Lines. Objects can be outlined with thin
lines by first printing them in (for example) black. Then, overprint a
second layer onto the same region, using a light opaque enamel. When fired,
this results in a thin dark line around the object, as shown in Figure
C. Shadows: By applying two complementary patterns that are offset from
each other by a small amount, a shadowing effect can be created, as shown
in Figure 14.
D. Textural Effects Resulting from Thick Applications of Enamels: The
enamel suppliers of the world will love this one. By printing large amounts
of enamel, it is possible to achieve very thick layers of fused enamel,
thus creating interesting 3-dimensional, textural effects. In summary, I have described a way to place dry enamels on metal, using
a screen printing method based on a coarse screen and a photo emulsion
mask. It opens up a whole new world of designing with enamels. Try it,
you'll like it.