When I took offset printing in college decades ago. We had
thermal expanding ink. A heat lamp over the output tray
caused it to expand. It was sometimes used for braille
printing but I have not heard of it having been used for
this in recent years. My daughter is visually impaired but
does not need braille. She works at the Central Association
for the Blind and visually Impaired in Utica, NY. I'll have
her ask about this.

Allen

-----Original Message-----
From: piclist-bounces@mit.edu
[mailto:piclist-bounces@mit.edu] On Behalf Of Peter
Sent: Sunday, April 21, 2013 5:38 AM
To: piclist@mit.edu
Subject: Re: [PIC] Pin-outs for 16F628 and 12C5X

Adding to what I wrote before about embossed printing of
pinouts and certain
schematics on cards for unsighted people:

I looked it up and I could not find the equipment I was told
was used to
make the cards which I saw. However, I found useful
information on eBay and
elsewhere, specifically:

1. eBay regularly sells Braille embossing printers which, I
suspect, are
simply dot matrix printers with a special head and platen.
One can certainly
print graphics on most of those, assuming they have the
right firmware (most
dot matrix printers had that even if only at low
resolution), so printing
one's own schematics on card (semi embossed?) using a $50
(current lowest
price I could find on eBay) Braille embosser printer should
be feasible. I
postulate that, based on my previous experience with
unintentionally raised
dot matrix printer output, a normal dot matrix printer could
be used as is.
Ime the output from a 7 pin row dot matrix printer used to
print on
triplicate (3 papers 2 carbon sheets) form sheets was raised
plenty on the
back side of the front sheet. Simply putting a blotting
paper behind the
card and printing with a normal dot matrix will likely raise
or emboss the
writing enough on the front sheet for comfortable finger
feeling. Don't
forget to mirror the design left/right as the embossing
comes out raised on
the 'other' side of the sheet.

2. There is something called embossing powder, which is a
thermo-fusible
powder which can be applied to freshly printed inkjet
printer pages, while
wet from printing, then set using a heat gun (which also
dries the wetness).
This link explains how it is done:

  http://www.theartfulcrafter.com/wet-embossing.html

The process is quite simple but likely requires a sighted
person to perform
it, and, also, proper settings on an inkjet to leave the
sheet suitably wet
for powder adherence.

Now that I think back, the embossed items I saw were likely
made with the
method at #2, since I have no memory of an indented back
side. I think the
cards were mounted on some sleeve so I could not see the
back side.

Anyway this is an interesting technology, I wonder if it can
be used to
print labels on boxes and panels, it can probably be tuned
for that,
assuming the melting point of the embossing powder is lower
than that of the
plastic box material.

-- Peter


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