How to clean up full color pics for black/white print?

[abrogard]

we only have an old black and white office printer.

from time to time we want to print out images that are full  color or close it it.

then the printer wastes a lot of ink doing a dark background and incidentally obscuring much clarity.

is there a way to deal with this probably fairly common problem?

here is today's example:  


color image

[sallyanne]

You could destaturate your image at luma in gimp
or (you are given a couple options there)
Colour to gray, duplicate your image and use multiply layer mode. Sharpens the image.
I just saw in color to gray you can enhance shadows too - so may be the one you are looking for.

[rich2005]

To All, please keep politics out of the posts and just for this case concentrate on a coloured map image.

Apparently (from deleted post) the problem is ...only issued our office with a 1989 dot matrix printer.

There are good reasons for using dot-matrix printers, fanfold-multi sheet carbon copy stationary for example. I once sold my 24 pin Panasonic for a really good price. Obviously the print is either black or white

What might work is dithering the image. I would normally use Imagemagick for this but it wrecks the text., Using Gimp, try the Newsprint filter - black on white and circles.

A bit of work before  and after.
Work with layers. (1)
Desaturate the coloured image. (2)
Copy the layer, apply the Newsprint filter and put the layer mode to lighten only (to try and recover the text) (3)

   

Still not black and white, so maybe a final Apply Threshold.

   

Not very pretty but a possibility.

[abrogard]

Thankyou for those posts. Sorry I didn't get back earlier. I'll give them a try.