Barks-issues and the word blueprint

[Dan Shane]

Anders Christian Sivebaek wrote:


> I'm very happy to find that the norwegian paper VG (tabloid or what
> would you call it?) printed an article with the blueprints of the Bin.
> Why is it call blueprints btw? They are of course blue in the story,
> but the normal drawings of houses that I've seen, eg. my fathers and
> the cantina going to be to build in our school, are white with black
> lines. any special reason for them to be blue?
>

And I reply:

These days just about all technical drawings are created with the aid of
Computer Aided Design programs (CAD), and are printed out as black lines on
white paper.  But before personal computers all drawings were done by a
human being with a pencil in his hand.  Imagine that!  It baffles science!
(Yes, Don and I watch the same movies.)

After the drawing was complete, the only way to make copies of the drawing
for the builder to use was to create *blueprints*.  The process involved
laying the original drawing under a piece of light sensitive paper, then
exposing the paper to bright light.  The light would not pass through the
areas where the dark pencil lines and text were present.  After exposure,
the light sensitive sheet would be immersed (sometimes in a simple glass
tube) in an ammonia gas that turned all exposed areas of the paper blue.
The areas that had been shielded from the light by the drawing would remain
white, the original color  of the paper.  This produced the cool looking
white lines on blue background.  The builder would never work from the
original white sheet with the pencil lines, but from the copies, or
*blueprints*.

There is your explanation, Mr. Blandings.

Dan Shane
(danshane at bellsouth.net)