| Sawtooth |
The
effect of a stencil that leaves a printed image that conforms to
the mesh of the fabric rather that the desired clean contour of
the image. |
| Screen |
1)
Pattern etched into image on the Plate to stop the doctor blade
dipping in. 2) The assembly of frame, mesh and stencil, through
which a print is made. |
| Scuffing |
A
print defect which causes the print to mark severely when rubbed. |
| Seediness |
A
defect in a varnish caused by small particles which sometime become
visible by transmitted light. |
| Self-Adhesive |
A
substrate which has been coated with a permanently tacky adhesive. |
| Self-Solvent |
An
ink with the ability to dissolve dry films of itself (or rewetting). |
| Set-Off |
Where
undried ink is passed from the image on one sheet to the reverse
of the next sheet in the pile See offset. |
| Settling |
The
deposition of solid constituents, i.e. pigment, extenders, in an
ink on standing in a container. |
| Shaker |
A
device used for mixing ink where a closed container is vigorously
shaken. |
| Sheen |
The
gloss seen at glancing angles on a surface which when viewed normally
appears matt. |
| Shelf-Life |
The
time that an ink will keep in good workable condition when stored
in the original sealed containers under normal storage conditions. |
| Shop |
An
area where printing is done. |
| Shore
Hardness |
A
unit of measuring the hardness of the material used to make silicone
transfer pads and squeegees. |
| Silicone |
A
material that can be friend or enemy. In the pad it is essential.
In the ink it reduces pick up. Silicone used as mould release during
the moulding process can cause miss - print or poor adhesion. |
| Sinkage |
The
blotchy effect caused by "sinking in" to a printed substrate
in the porous areas. |
| Skinning |
The
formation of a surface skin on inks or varnishes in the container. |
| Solvent
Strength |
The
ability of a solvent to dissolve materials. A strong solvent will
dissolve many materials, a weak solvent will dissolve few materials. |
| Solvents |
A
liquid which dissolves the resin used in the printing ink. Sometimes,
synonym for "Thinner". |
| Spatula |
Used
to pull the ink from the ink trough over the Plate. Normally metal,
can also be plastic or brushes. Also called a spreader. Also a flat
device used for stirring or mixing inks. |
| Spectral
Match |
Inks
are spectral matches if at each wavelength of the visible spectrum
their reflectancies are the same, a spectral match holds good for
all illuminants and observers. |
| Spectral
output |
This
is the output shown in nanometres of a lamp usually ultra violet
curing lamp. |
| Specular
reflection |
Reflection
of light as in a mirror. |
| Static
or Static Electricity |
Generated
when two dissimilar surfaces rub together. It can cause prints to
stick together or printing defects (of cobwebbing). |
| Stoiciomectric
point |
The
point in a gas flame that is the most effective at altering the
surface energy of a substrate. |
| Stoving |
The
process of drying and hardening an ink coating by heating, usually
at a temperature of above 80o C. |
| Streaks |
Elongated
defects in a printed image. |
| Sublimation |
The
process whereby certain dyes change directly from a solid to a vapour
and back again to a solid by the application of heat. Inks containing
these dyes are used for printing onto polyester materials. |
| Surface
Tension/Surface Energy |
The
force associated with the surface of a liquid. If an ink is to adhere
to a substrate, the surface tension of the ink must be lower than
the surface energy of the substrate. If these get closer the ink
will show, as the difference reduces, defects ranging from pinholing
to reticulation and finally no adhesion. |
