Hi Guys!
The big picture shows a fame with three masters on it.
Oh yes you might say they put the panel in and print in three passes.
Er no. having three different colour inks sloshing around in a frame
at the same time might cause a few problems.
From bottom up we have Terracotta, then amber and finally white.
First they line up the blank panel with the Terracotta master and
screen all the blanks with that colour.
They go into a special rack to dry. Now they have to get rid if every
trace of Terracotta ink without
messing the master up.
They like to leave 12 - 24 hours between passes. (Overnight if they can) .
They repeat the process for Amber .
Finally we come to the White layer.
Try putting a 1mm white line between two different colours ,
always keeping the two colours on the correct sides of the line with no
gaps.
OK thats what they did with the first batch. Generally they were very
well received and looked good.
I asked for feed back and one list member said the real ones appear to
be matt black on the front.
I got an old panel shipped over because I thought it was just age and dirt.
Well it wasn't matt black nor was it dirty. They had put a translucent
layer on the front that helped to deffuse
the light from the lamps and had this strange optical effect of making
the front look matt black.
Going back to my DEC days I think the the general view was they were
matt black on both front and back
to stop unwanted reflections due to the point light sources from
filament lamps.
So I asked if we could get some suitable ink. and try it out. Well the
answer came back that whilst it was fine
for deffusing the light over the holes on the back , they were not
happy with the results on the front.
A thin layer of real matt black on the front was much nearer the sample
they said.
So I added a thin matt black layer on the front for the current batch.
You can't tell the difference.
I think I know what may have happend. If you put a layer of matt black
on the front you need an extra screen
with holes that line up with those on the back. A translucent layer just
goes right across.
I believe it was intended to be black on both back and front but
somebody did a bit of cost engineering.
Well two can play that game and I have come up with an answer. From my
normal supplier I have been able to
source our standard 3mm perspex but with one side having a silk finish.
It minics the effect of the old plastic
with the diffusing ink perfectly! The front looks matt black. It also
makes the ink adhere better
Saves putting a front matt black layer on future batches and you cant tell.
Rod
