NewsCraft LGN paper is a specially coated
translucent paper designed specifically for printing applications to embody
three major characteristics:
- Dimensional stability
under heat and pressure.
- Superior toner
adhesion and durability.
- Increased
transparency, particularity to UV light.
Due to these unique properties, LGN paper has
found acceptance in a wide range of applications such as screen printing, sign
manufacturing, printing with photopolymer and both positive and negative metal
plates, glass and stone etching, circuit board layout, and others. It has been
used successfully in both process and spot color applications requiring
accurate registration.
Use of LGN paper does not require special
computer software and can be used with most MacIntosh and Windows
based software. To get the best results with LGN a laser printer capable
of producing solid blacks is required. Laser printers manufactured by
ColorScan (formerly LaserMaster), Xante, NewGen,
GCC, Hewlett-Packard, Apple, Lexmark, and Canon
have all been used successfully. This does not mean that other brands of laser
printers will not work, only that we have not had direct experience with them
reported to us.
Following a few basic guidelines will assure that you
get the best possible results with LGN. If you still have problems using
LGN please call System Facilities at (315) 234-2348 and ask for
LGN User Assistance.
Step
1: Make sure that your laser
printer is clean. Carefully follow the cleaning directions included with your
printer. Remove excess toner and paper lint that may be in the paper path. A
clean printer will produce a more even image.
Step
2: Set the toner density as
dark as possible for your printer. You want maximum toner coverage so that the
blacks are as solid as possible. DO not be concerned about using extra
toner.
Step
3: Keep the LGN paper
in a dry environment. An air conditioned workplace is fine. High humidity, such
as opening the windows on a rainy day, will cause stretch and toner adhesion
problems.
Step
4: When exposing a screen,
plate. etc., make sure that the toner side of the LGN is down - against
the emulsion on the screen or plate. This prevents light from leaking under the
toner and causing blurred edges. Depending on what type of printing you are
doing you will need to be able to create either a right- or wrong- reading
image In either positive or negative form. In most computer applicators this is
usually done in the options item in the Page Setup function by using the Flip
Horizontal and Invert option check boxes. Note that some applications, such
as Aldus PageMaker 5.0 and Adobe Photoshop, have options called
Make Negative and Emulsion Down which perform the same
functions.
Step
5: Exposure times for
LGN may vary from film depending on the medium being exposed and the
type of lights in use. For screen printing begin by exposing LGN for the
same amount of time as you would film. For metal plates start by reducing the
burn time by 20%. For photopolymer plates begin by increasing the burn time by
15%. Based on the first test the burn times can be adjusted for best results.
If you burn through the toner area reduce the burn time by 10% and try again.
If you are not getting hardened emulsion or photopolymer then increase the burn
time by 10%. You may have to repeat this process several times until you arrive
at the correct burn time for your particular setup. Usually, the adjustment
will be within 20%, but do not be concerned if the burn time goes up or down by
as much as 50%.
Step
6: When doing halftones and
process color separations, laser printers are limited in how fine a screen they
can produce. A 12OOdpi laser printer can produce up to an 85 line screen.
Beyond that, banding will occur in the image due to a reduction in the number
of color/gray changes that can be physically represented. An 18OOdpi laser
printer may be able to produce a finer screen - say 106 lines - but the
limiting factor becomes the size of the toner particles. Try screens in a test
before using them in production. Lower-resolution laser printers will produce
correspondingly coarser screens.