[Blindmath] Tactile embosser Resolution

[John Gardner]

Hi George, it would be good to have some agreed-upon way to distinguish the
difference between accuracy of dot placement and the minimum distance
between dots.  Both could be called "resolution" unfortunately.  I guess I
just need to be sure to remind our marketing folks that they need to avoid
this confusion.

John


-----Original Message-----
From: George Bell [mailto:george at techno-vision.co.uk] 
Sent: Thursday, December 18, 2014 8:19 AM
To: john.gardner at oregonstate.edu; John Gardner; Blind Math list for those
interested in mathematics
Subject: RE: [Blindmath] Tactile embosser Resolution

Hi John,

Dare I suggest a better term might be to refer to, "Resolution" as distinct
from DPI (Dots Per Inch)?

George.

-----Original Message-----
From: Blindmath [mailto:blindmath-bounces at nfbnet.org] On Behalf Of John
Gardner via Blindmath
Sent: 18 December 2014 15:58
To: 'Ian Chris'; 'Blind Math list for those interested in mathematics'
Subject: Re: [Blindmath] Tactile embosser Resolution

Ian, this is just another example of how some manufacturers imply more than
what actually occurs.

The new ViewPlus Embraille embosser has a resolution of 300 dpi in the sense
of this 50 dpi number you quote.  But we do not say that.  At least not
without some explanation. 300 dpi is not a measure of how many dots can be
embossed in a one inch line - it is the accuracy with which a dot can be
placed on the paper.  50 dpi is actually a pretty crude value if one wants
to produce braille with official NLS spacings.

You could never emboss 50 dots in a one inch line.  Or rather, if you did
emboss 50 dots per inch, you would just be embossing a big mess.  And it
wouldn't help.  Anything more than 20 dpi is beyond the resolution of the
static sensors in fingers.  Few people can distinguish 20 dpi line from a
solid line when just placing a finger on it.  If you move that finger or use
a fingernail, you can tell the difference, but it doesn't actually provide
any more information. 

Hope this helps.

-----Original Message-----
From: Blindmath [mailto:blindmath-bounces at nfbnet.org] On Behalf Of Ian Chris
via Blindmath
Sent: Wednesday, December 17, 2014 10:54 PM
To: Blind Math list for those interested in mathematics
Subject: [Blindmath] Tactile embosser Resolution

Dear List members,

I was studying the tactile outputs of a braille embosser, it says that the
resolution (for tactile embossing)  is 50 DPI, which in printing terms shall
mean that there are 50 dots in a length of 2.4 MM. In other words there are
50 projections in a straight line if embossed in an inch that is equal to
25.4 mm.This shall mean that the dot size is 0.5 MM in diameter.
All the above is just a theoretical assumption.

If i have to fit in 50 dots in a row 0.5 mm with no spacing in between my
assumption is that the dot diameter read the projection diameter or the
surface area is equal to 0.5 mm. Now if if have to distinctly feel each dot
there has to be a minimum separation between the two. I am confused if i can
get the resolution of 50 DPI in the embossing.


Experts may comment on the same as it is not leading to any understanding of
the embossing possibilities for one of my samples. also this is not specific
to a specific brand of embossers. The sample that i am working on is also
one of its kind and has no significance whatsoever but this inability to
understand is driving me crazy.

Regards,

Ian
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