The Principle & Basic Setup
- Properly used, the PrecisionMask System will
allow you to accurately reproduce every detail of an
artwork as an engraving in glass.
- To produce good engraving, therefore, the first
essential is good artwork. The artwork itself should
be clearly defined black and white. If any shades of
grey are required, they must be provided by using
different sized dot or line tones (except for
PrecisionMask Intaglio, see separate instructions).
- The artwork should be surrounded by a thick black
border, approximately 2mm wide, equidistant and
square around the image, about 5mm from the edges
of the detail...
- This border will assist:-
- When laying up multiple images.
- When cutting the finished PrecisionMasks.
- To square up each PrecisionMasks when
positioning it on the substrate to be engraved (you
may also like to put a centre mark at top and
bottom to assist with this).
- To prevent the PrecisionMask curling away from
the substrate when the adhesive is wet.
- To make it easier to pick up a corner of the
Carrier Film for removal, when the adhesive has
dried.
- Finally, a letter "R" placed in the top right hand corner
of the artwork (as shown) will help make sure that
the final PrecisionMasks are applied right side up.
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The Artwork Itself
- It is the black areas of an artwork that end up being
engraved.
- Compared to the engraving, which is white, glass is
effectively a black background. Thus, to engrave a
white image on glass, a white sail with dark lettering,
for example, a negative artwork is required, i.e. a
black sail with white lettering. This is true for faces
too, which should be filled black, with white eyes,
mouths and shadows.
- Dots and line weights as fine as 50microns (2 thou or mil)
may be engraved by underexposing PrecisionMask
film as per the instructions for halftones, but 125microns (5 thou or mil) is generally fine enough for most images.
- If you are drawing an image or logo by hand, draw
it at four times the size and line weight that you want
to engrave so, when it is shrunk down to 25% size,
it will crisp up nicely and any slight wobbles will
disappear!
- To engrave photographs, see How to make Halftone PrecisionMasks.
The Master Positive
- From the artwork, the next stage is to produce a
positive transparency. It is important for this to be
as definite as possible, with an opaque black image
on a clear background.
- The emulsion or toner must be on the right reading
side of the transparency.
- For text and normal artwork, use a laser film printout,
treated with a toner density enhancer.
- For fine details and particularly for halftones, a film
positive from a process camera or image-setter is
essential. Ask your bureau for "positive film, right
reading, emulsion up".
- When setting out transparencies for exposure, ensure
that an unbroken border of exposed stencil film
(approx 10mm or more) will be left all around the
edge of each sheet. This will make it easier to peel
the completed PrecisionMasks during manufacture.
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