Cleaining up old floor plan

[alke]

I got a whole bunch of 20 y.o floor plan scanned from paper that needs cleaning up. I cant dedicate to much time on this, and it doesnt have to be perfect.

Here is an example http://i58.tinypic.com/2115ljm.png

 

I tried the following:

Convert to Black & White

Magic Wand: tolerance 20 - Delete

Effects - Photo - Sharpen - 20

And then cleaned it up a bit.

The result is almost good enough, but could be better:

http://i59.tinypic.com/md2z6g.png

 

I think I should be able to use the Adjustment - Levels tool some how, but i dont really understand how it works.

[alke]

I've been playing around with the "curves" settings, and that might be the way to go.. See example below.

If you think there is a better way, or something i should do in addition to adjusting the curve, feel free to add any idea you might have!

[xod]

You can try Scan Tailor but you need images scanned at minimum 300dpi  resolution (grayscale) to get excellent results.