Front Panels - PDP8 and PDP 11
rodsmallwood52 at btinternet.com
Wed Mar 2 16:32:36 CST 2016
Having got 8/e (A & B) plus 8/f and 8/m into
production its time I made a few comments.
The aim has always been to reproduce the original panels using the
process DEC used all those years ago.
Needless to say we had to go through the learning curve with only
photographs, scans and one 8/m original
panel to go on.
In the interests of origiality I have kept what we used call 'features'
as found in the documentation and the sample we had.
I'm trying to reproduce the original, not produce an improved or fixed
The only process deviations I have allowed myself are as follows:
1. The original versions would have been drawn twice full size by
hand on matt paper in indian ink.
One sheet per colo(u)r would have been requred. They would
then have used a process camera
to reduce to one to one positive masters on clear acetate film.
The cameras (they were huge) and the darkend rooms they worked
in no longer exist.
I used to do just that in the early '70's but whats weird is
where I worked is less than 50 yards
from the silk screen studio doing the work now.
Now I use Inkscape and its layers to do the same thing. The
screeners have an Epson printer
the size of a piano to print my layers in black onto clear
film. After that the process is the same as it was.
They take a fine meshed cloth streched onto a frame. Its
coated (by hand) with a photo sensitive
emulsion, when dry it gets exposed through the master using
a UV light source.
The the parts proteced by black on the master are water
soluable and get washed out and hence
let the ink through. So one screen per layer is required
2. DEC would have printed the images first and routed or milled the
holes using some kind jig later.
As long as the hole stayed inside the white line that was
deemed to be OK.
We drill (laser cut) first and screen afterwards.
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