It is said the first decorated T-shirt was produced in 1939 to
promote the movie "The Wizard of Oz." Prior to that time, T-shirts
were mostly white and considered underwear. Today, imprinting or applying a
surface graphic is often all that distinguishes what are otherwise commodity
products, dramatically increasing their market value. This is as true of
ceramics and glass as it is sportswear. Decals are a flexible option whenever
you have a surface imaging requirement.
PRE-TESTING and certification of performance of a
variety of quality assurance specifications such as metals release,
durability, adhesion, and surface compatibility.
PRE-SELECTION for quality appearance requirements such as hue, gloss
density, opacity, reflectance, brightness, sharpness, size, and shape.
PRE-INSPECTION for reduced manufacturing spoilage such as multiple
color registration, or cosmetic flaws or defects.
LESS HANDLING since each part is touched only once even for complex and
ARTISTIC FREEDOM providing detailed graphics on compound or complex
SIMPLIFIED PURCHASING since there are fewer raw materials to acquire,
inventory, and manage.
IMPROVED PLANT SAFETY by eliminating flammable printing inks or fluids,
solvent odors, hazardous waste disposal problems.
Other Benefits of Decals:
PRODUCTION FLEXIBILITY AND INVENTORY CONTROL
FAST CONVERSION AND PATTERN CHANGE
SIMULTANEOUS DECORATING OPTIONS WITH WIDE TOLERANCE TO PROCESS VARIABLES
LOW CAPITAL COSTS
REDUCED FACTORY SPACE, DOWN TIME, SKILLED LABOR,
2. How Decals Were Made
The decal starts with art work, supplied by the client or
created by our own Giraphix ™design studio. Through manual or electronic means,
the art is separated into black and clear positives for each printed color.
These positives define the open mesh areas where the ink will pass through the
screen to the decal paper.
These separations contain two types of print, half tones (small dots of varied
sizes which produce shading gradients) and lines or solid areas which are
scaled, repeated, and pin registered. A screen mesh and stencil emulsion which
are compatible with the half tone dots and desired ink deposit are selected. The
mesh is stretched taut on a frame before the emulsion coating is applied and
dried. Each color's transparency is placed in contact with the framed screen
under vacuum and exposed to ultraviolet light which burns and hardens the
The unexposed (positive) areas remain soft and are washed away with water. While
the screen is being produced, ink materials such as pigments, glass frit,
solvents, resins, and binders, are mixed with high intensity to form a thick
paste suitable for screen printing.
The pigments and glass frit, which are the only materials that remain after the
firing process, are carefully selected for compatibility with the customer's
ware, firing process, and end use. Printing is accomplished on automatic
cylinder presses, by skilled operators. Each color is sequentially printed on
specially coated decal paper and air dried, in a process that can take several
days. Finally, a clear or colored cover-coat of lacquer is screen printed over
the graphics to transfer the graphics during application.
Prior to shipment, each decal sheet is counted as it goes through a final
quality inspection (see Inspection Criteria) and a test firing is performed.
Printing and ink data along with the color separations are filed for future use
and reference. The decals are shipped in a re-closable long term storage box
with pertinent information printed on both the box cover and decal sheet.
3. Glass, Over-Glaze, In-Glaze
Vitricals™ are decorative markings for glass, ceramic and
vitreous enamels. They are water slide decals which are applied by conventional
soaking and squeegee methods. After firing, they provide a permanent surface
Vitrical™ decals can be formulated to fire onto materials ranging from low or
high expansion glass to hard porcelain. The choices allow for production of many
possible colors and opacities. Our state-of-the-art printing machinery can
produce Vitrical™ decals in single colors. in high resolution Multiple colors (20
or more), and in process color. They can be produced from Custom artwork or from
our own stock patterns.
Vitricals can be formulated to fire at many different firing temperatures which
is determined by the melting temperature of the FRIT or glass portion of the
1. Lead Crystal: 980-1030°F
2. Soda Lime Silicate: 1050-1100°F
3. Borosilicate: 1200-1250°F OVER-GLAZE
1. Earthenware: 1380-1470°F
2. Bone China: 1430-1500°F
3. Soft Porcelain: 1400-1520°F
4. Hard Porcelain: 1430-1580°F IN-GLAZE
1. HIGHLY GLAZE DEPENDENT- 1800-2400°F
NOTE: While all vitreous markings are durable by
nature, with good adhesion, abrasion and chemical resistance, in-glaze are the
most durable and best suited for extreme conditions. They typically are used for
most commercial dinnerware and many tile applications.
4. Water-Slide -Pad Transfer
Water-slide decals (Vitricall™) are applied by hand and have
the most flexibility to conform to complex and compound shapes.
Heat Transfer (Vitramark™) decals are applied by machine where a soft heated
pad picks up the graphics from a hot plate which has melted the wax coating on
the paper. When it makes contact with the surface to be decorated, the wax
re-freezes, adhering the transfer for firing.
5. A List of our Products and
High quality transfers for Ceramic Glass, and
Machine applied markings and pad transfer
A fully adjustable, rapid clamping fixture. It
frees the decorators hands and permits 360 degree rotation
Digital output proof in decal form to produce
compelling working models of your idea.
Technical application transfers. They may
possess mechanical, electrical, or chemical properties. As active decals,
they combine form with function. Touch-screen capacitors, Bake on Identification,
Electrical Markings, Conductive transfers
Decals Designed for Raw glaze application
6. Finishing, Shipment, Storage, and
One issue commonly questioned but more often a primary cause
of defects in the fired product is decal storage method. Our fire on decals,
trade-marked Vitricals, are composed of a variety of materials, each with unique
and varied sensitivity to changes in environmental or atmospheric conditions.
The most stable materials are the frits and pigments, which, in their powder
state require extreme temperature or corrosion to change their form. However,
the dry organic materials in which these powders are encapsulated and the paper
onto which they are printed are quite sensitive to storage conditions. The water
soluble starch adhesive paper coating and the paper fibers themselves are both
sensitive to temperature and humidity.
The dry cover-coat and printing medium which act as transfer film and binder are
composed of trace solvents, plasticisers, and dissolved polymers. These organics
are sensitive to oxidizers and ultraviolet light. When left in open air for
extended periods of time, the organics will "dry out" often resulting
in decal tears during application and fired defects such as pits. (Pits in the
fired ware can result from many causes, which will be discussed in a later
chapter). Fortunately, "dried out" old decals can be salvaged at a
fraction of their original cost by having the manufacturer print a cover-coat
Finally, decals, which are subjected to pressure, from horizontal stacking and
heavy weights, can cause the decal sheets to stick together and the organic
materials to bind and deform. Waxed slip-sheets and non-blocking over-coats help
prevent stuck sheets. We ship slip sheeted decals in boxes and plastic bags
designed to be used as permanent storage containers. The boxes should be stored
closed, vertical, and in air at 55 - 80°F and 40 - 60% relative humidity. It
has been reported that decals have been applied and fired successfully after
being stored properly for several years.
Note: To ensure longest possible life, decals should remain stored vertically in
their box. Do not expose decals to extreme cold or hot temperatures or dry and
humid environments. We recommend storage at 55-80°F and 40-60% relative
humidity. Criteria for inspecting decals The following list represents the nine criteria for which each deal is
checked during final inspection.
Registration targets should overlap. Colors align uniformly. Abutting fits and
color traps must leave no gaps around printed areas.
2. COMPOSITION Size, shape, layout, and printed text must match the standard. There; must
be no distortion, enlargement or reduction from the original.
Halftone dots must show contrast, sharpness, and detail. Solid colors must be
uniform and dense. The print should match the standard.
4. SHEET UNIFORMITY
No variation across the sheet or from sheet to sheet.
5. STRAY OR MISSING COLOR There must be no extra printed areas or holes.
6. INK FLAWS
There should be no smudges, splatter, ghost images, pinholes, or fisheyes.
7. COVER-COAT FLAWS
There should be no pinholes, fisheyes, splatter, missing areas, thin coverage,
lumps, smears, or off registration.
9. FOREIGN MATTER There should be none. Fibers, dirt and airborne dust must be kept to below
a minimum acceptable level.
9. CREASES OR TEARS There can be no folds, perforations, creases, or tears in the paper
through the decal.
Die Cutting Die Cutting is a process by which individual decals or groups of decals can
be cut and bundled in a defined shape. This can include center notches to help
align decals during application. Our decals are not supplied die cut, but such
service is available at extra cost.
Editions and Lot Numbers Each of our decal sheets includes a lot number, typically in the form of
XYYYY; Where X is a letter code and YYYY is a four digit number (132045, for
example). This lot number is a key tracking number used to file process and
billing information. From it we are capable of tracking: ink formulations,
creative materials, printers books, and shipping records to name a few. If you
cut decals from the printed sheet, it is important to keep this lot number with
each separate decal bunch. It is not a good idea to combine decal of different
lots until you have confirmed performances of the decals.
A look at an inspected sheet The decal sheets, which are shipped to you, include not only the lots number
information, but also an inspectors mark. This mark is a colored check of red,
orange, yellow, green, bright green, crimson, purple, or blue.
Any defective decals on the sheet will be crossed out in the color of the
inspector's pen. Each inspector keeps a tally of cross outs and these are
subtracted from the total to yield and "equivalent sheet" for billing
For those who inventory decal sheets produced by us before October 1995, our old
marking system used a blue inspector number stamp and either a black or red
The inspectors mark (pen color or number) allows us to track service related
issues should the customer encounter any rejects. When reporting rejects to us,
it is important to provide the lot number and inspectors identification.
How to apply water slide decals WET THE DECAL in a pan of water, which will cause the paper to curl. Remove
to a flat surface and let the decal flatten (typically about 20 seconds). Tap
water may be used for wetting. But, when high mineral content is present,
de-mineralized water avoids fired defects. A soluble food grade starch paper
coating adheres the decal to the ware before firing. Over-soaking the decal to
float free of the paper must be avoided as this may cause pre-firing adhesion to
be lost. Replace water when it appears cloudy. When the decal must stretch over
a curve, soak the decal and/or ware in warm water allowing the decal lacquer to
become more flexible and easier to apply.
SLIDE THE DECAL from the
paper in position on the ware making sure the surface is free of all
debris before the application of the decal. Pollutants like dirt and oil
between the decal and ware may result in fired defects,
REMOVE THE WATER from between the decal and substrate by pressing
with a rubber squeegee and/or a soft cloth. The squeegee is easily
lubricated by rubbing it over the wet decal paper once the decal has been
removed and placed on the ware. Once this squeegee procedure has been
completed, no water pockets should remain visible.
DRY THE DECAL thoroughly,
to avoid "blowout" blisters during the firing process. Although
I to 2 hours may be sufficient, many decorators prefer to dry overnight.
Others will dry the decal in minutes with warm air in a preheat process
below the boiling point of water. One suggestion is to dry at 95°C for 10
FIRE THE DECAL in the specified time/temperature range. Be sure to
leave sufficient time for the heat to "Soak" the ware at a
temperature, which allows the decal to mature. (See
Squeegees Application squeegees made of soft rubber or urethane are used to
press the decals onto the surface while removing the water. They can be
obtained in a variety of shapes. Lubricating the squeegee with the
residual gum left on the paper can prevent tearing of the decal.
We offer extremely durable decal decorating squeegees made from tough
70-durometer cast polyurethane rubber. These squeegees are 5 mm thick cut
nominally 26 by 2.50 and feature both a hard square edge and a soft chisel
edge. They are well Suited to flat or intricate hand decoration and fit
comfortably to the operators hand.
and other Fixturing Tools
Many decorators will fabricate holding fixtures for their ware to speed decal
application times by freeing up a decorator's hand. Typical attributes of such
fixtures include quick load and unload process, low investment cost and easy to
store. We developed a fixture trademarked D-Vise which, in addition to the other
attributes, offers flexibility. Standard, manual and pneumatic models rotate a
full 360 degrees and can easily adjust to clamp anything from shot glasses to
Vitramark and other Pad Transfer Machines
There continues to be increasing interest in the pad transfer technique of decal
decorations. There are highly automated transfer machines on the market starting
at prices from $18,000 to $125,000. Philadelphia Decal offers a Vitramark™
machine to introduce low cost flexible automation into hand decorating
production lines or to support users of the highly automated machines at a
research and development level. Machine operating principles are the same and
each uses the same types of decals. Unlike the more expensive machinery, the
Vitramark™ pad moves manually between indexed stations by the decorator's hand
in a simple and fluid operation.
Pad transfer utilizes a flexible heated silicon pad to pickup
a multi-color decal decoration from heated waxed paper. The pad then places the
decoration onto a flat, cylindrical, or irregularly shaped room temperature
glass or ceramic surface where residual wax on the decal underside freezes to
hold the decoration in place. Unlike waterslide decals, no drying time is
required and ware is ready for immediate glass, over-glaze or in-glaze firing.
Also, there is no squeegee or alignment time required. So, decorating speeds per
operator are substantially increased.
Application speeds can vary depending upon decal
characteristics, specific ware shape, and decorator expertise. The
following is a general guide.
• Spot Decal 100-200
• Small Bottle/Tile
• Full Wrap Mug
• Full Skin Collector Plate
• Lamp Base
8. Proper Firing
An understanding of the dynamics of a proper firing requires
the following knowledge of decal chemistry and basic kiln technology: Remember
that the objective in firing ceramic decals is to melt and fuse tiny inorganic
particles of glaze pigments to the substrate in such a way as to achieve the
desired appearance and properties. Each decal component has a functional purpose
and can be affected by firing conditions. An improperly fired decal can result
not only in poor appearance, but also in poor adhesion, detergent durability,
toxic metal release, and abrasion resistance.
Our decals are produced in a screen printing process and contain organic
adhesives, printing oils, and cover-coat that are designed to vaporize and
combust during the firing process. These materials, when fired properly, leave
no ash deposits and will not affect the final appearance and/or properties of
water slide decals are printed on a starch coated paper and applied using
water which allows the decal to transfer. These decals must be thoroughly
dried at temperatures less than 100°C (212°F) before firing. Otherwise,
boiling water will lift and pit the decal's surface during firing.
decals use a special waxy hot melt adhesive and can be fired immediately
after application. It is important that the graphical portion of a decal
does not overlap the cover-coat edge of another decal.
The organic materials burn away during the firing in the range of
150-350°C (300-750°F). If the firing is too rapid, pits in the final
decoration can result. This pitting due to rapid fire occurs because the colors
melt and begin to fuse to the ware before the organic compounds completely
vaporize and burn away leaving the organic trapped in the decal. However, unless
the decal is placed in a flame, it is rarely the maximum rate limiting factor in
the firing process. More typically, it is the ware which must be fired slowly
due to its expansion, strength, and heat transfer characteristics.
Once the organic are burned off, only the inorganic powdered materials remain on
the ware. These powders sinter, melt and fuse to the ware in the upper
temperature range of the firing cycle. About 90% of the powder is glass frit or
flux, selected for (among other criteria) its compatibility with the ware glaze.
The other 10% are usually a variety of pigments, selected for their appearance,
chemical properties, and compatibility with the frit and firing conditions.
Firing effects the decal pigments, composed of a mixture of metallic oxides.
These oxides, when properly fired, exhibit their desired color. If under-fired,
the powdered pigments will not fully melt and disperse in the flux. Instead,
they may remain as a powder and/or produce a dull or matte surface, which will
easily scrape away. Under fired colors may appear weak as well. If over-fired,
the pigments may lose or change their color because of their temperature
sensitivity (some pigments are sensitive to peak temperature differences of I
100°F and less). When over fired, the pigment mixture may exhibit the color of
one component or it may develop an entirely different color altogether.
Therefore, reliable temperature control is required to achieve satisfactory
firings. If loaded sections of a kiln or belt furnace are too close to hot
connective gas flows or other heat sources, they may become over-fired. In an
electric box kiln, "hot spots" can occur along the upper edges and
areas close to the heating elements. Proper sensor location and control
equipment help maximize the capabilities of firm,-, equipment. Independent
temperature recordings with sensors placed adjacent to the ware at strategic
locations in the kiln provide an audit and can help troubleshoot most firing
Proper firing requires both time and temperature to allow the organics a chance
to bum away and the frit materials to absorb the energy necessary to melt and
fuse to the ware. It's important to realize that heat energy flows from high
temperature air to low temperature bodies and that in firing conditions, the
surface temperature of the ware lags significantly behind the air temperature of
the furnace in accordance with the ware/air heat transfer characteristics. The
best way to assure proper firing is to allow sufficient time for heat to
"soak" the ware at a given temperature. Thicker ware requires longer
soak time. Typical glass and ceramic tableware require a five to twenty minute
soak depending on thickness.
Kiln atmosphere can affect decal firing, especially during organic burnout when
oxygen is required for the combustion process. Generally, fuel fired kilns,
which heat by combustion, have sufficient oxygen for organic burnout. However,
electric kilns require ventilation during the first stage of decal firing.
Without ventilation, electric kilns tend to produce reducing or oxygen deficient
atmospheres because the organics deplete oxygen as they burn away. To insure
proper firing, the kiln must be free of dust and dirt particles as well. These
particles can settle onto the cover-coat or the molten glaze and decal during
the firing. Inorganic particles can often be observed as specs on the cooled
ware; whereas organic particles will burn away but can leave pits where they
Furnace and glass engineers should be available for startup and consultation
when defining or troubleshooting a firing process. Philadelphia Decal offers
such engineering services in addition to comprehensive product Support and
laboratory testing services.
Periodic kilns - Belt and Roller Lehrs.
Typical examples of decal firing equipment.
Periodic Kiln and firing curve.
Belt Furnace (Lehr) and firing curve.
Photos Courtesy Noritake Co., Limited
9. Cost guidelines
How decals are priced
Decal costs are based on three primary factors, size, quantity, and the number
of colors. The first two are often very closely related because the size will
effect how many decals will actually fit on a sheet or within a defined area.
Customers are always encouraged to use the sheet geometry to their best
advantage. We attempt to spot weak layouts and make suggestions to improve sheet
yield whenever we can.
Ruled paper sheets called "Layout Forms" for layout planning, show
size and spacing limits and are available on request. A computer generated
Layout conformation, in quarter scale, can be taxed to represent any proposed
layout (see Layout Options).
Premium for precious metals and special effects
Many unique materials may be used to distinguish a design by adding texture or
otherwise enhance the appearance. Popular materials include precious metals like
gold or platinum. These are printed as organometallic pastes which when fired
are reduced to thin layers of high purity (23 carat) base metal. Prices are
determined by metal concentration of paste and yield (printed volume per unit of
area). It will fluctuate with the market prices of these materials.
For those who pay a premium for decals that contain precious metals such as gold
and platinum, collection and refining of decal scrap should be considered. While
it does not pay to send decorated ware to a refiner (due to the low weight
yield), decals can provide yields of several dollars per pound of scrap.
Therefore it is worth collecting such waste. Typically, refiners require a
minimum of two 55-gallon drum of material before they will process. However,
even if it takes a year to collect the material, the small amount of effort and
floor space can easily pay for itself.
From our studies, we have seen substantial variation in yields from the
refiners, so it is worth shopping around and sending split samples if possible.
Typically, the refiner will provide collection drums and transportation of the
material. Processing time is typically 3 to 4 weeks to settlement. Refiners will
require you to specify what precious metals are present in the decal scrap.
Obviously, gold bearing decals should be tested for gold; however, few people
realize that platinum inks contain substantial amounts of gold and palladium as
well. Philadelphia Decal would be happy to help you establish a gold reclaim
Proofing is an exercise that results in the production of physical samples of
the decal desired, usually 12 copies. It insures that all of the color
development, art, and printing techniques are correct and suitable for the
intended purpose. It is used to establish an approved standard to which all
future production will be measured. Production decals will be printed after
approval of the proof.
Proofing is not required for reorders or where line art is supplied in
"screen ready" form if the colors have been tested and approved. The
customer may otherwise decline it only upon the execution of a waiver.
Creative Art Services (see Girafix) and color separations are quoted separately
and incurred prior to proofing.
ink transfers (Decals) are in use today on, Busses, Pool
Cues, Glassware, Baseball Bats, Bird Feeders, Golf Clubs, Fiberglass Showers,
Bathroom Tile, Wall Murals, Basketball Courts, Boats, Ceramic Pendants,
Motorcycles Helmets, Fenders and Gas Tanks, Cigarette lighters, Whisky Flasks,
Guitars, Stainless Steel Thermos, Travel Mugs, Point of purchase displays,
Cameras , Cell Phones, Auto and Bicyclical Restoration projects. Just to name a