How were dot matrix pictures printed on Sears calendars?

[edward]

I found this old dot matrix of my children. It was printed on a calendar at Sears.

How did they do that?? I know they took a regular picture first.

 

[jedishrfu]

My guess is they used the pixels of your Black and White image and mapped a character with a corresponding density of dots. In addition the algorithm was probably was sensitive to sudden pixel changes and would try to find the best character to map. As an example if the pixel to the left and the pixel below a given pixel were dark but the pixel itself was white then the might use an '[' or an 'L'...

#############
##[_______]##
#############

Sample palette:

light gray:

...
...
...
...
...

darker gray:

XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX

black:

##########
##########
##########
##########
##########

so basically you could make a palette of characters to map to various shades of gray and then use that to construct the character based image. It was very popular before the advent of PCs and color printers.

Here's a program that do it:

http://www.glassgiant.com/ascii/

and google has many pictures organized unde the search term "Ascii Art":

https://www.google.com/search?q=asc...rEMMiIyAH1rYGgCA&ved=0CDAQsAQ&biw=969&bih=609

and here's another explanation of how it works:

http://stackoverflow.com/questions/394882/how-do-ascii-art-image-conversion-algorithms-work

 

[edward]

opps, I forgot the year it was made.

So how do I get a full size dot matrix Ferrari image on my garage door?

 

[jedishrfu]

opps, I forgot the year it was made.

So how do I get a full size dot matrix Ferrari image on my garage door?

Get one of those projecters that hook to a computer and display an image on your garage door and then trace out the image and then paint it on manually. Or better yet, hire some out of work grafitti artist or custom van painter to spray paint it on.

 

[edward]

Get one of those projecters that hook to a computer and display an image on your garage door and then trace out the image and then paint it on manually. Or better yet, hire some out of work grafitti artist or custom van painter to spray paint it on.

The Home owners association won't allow a painted on picture. I had hoped they might go for something less noticeable like a lot of little dots.

Thanks much for your help and the links.