Simplified Captcha

When I first put this blog up before Ray implemented captcha on comments I hardly wrote anything and was (and still am) not greatly linked to, but yet I was inundated with spam! It was ridiculous! I spent more time trashing junk than I did writing anything!
When Ray added Peter Farrell's Captcha and I turned off trackbacks that all went away and I actually started writing stuff even if it is a little sporadic.
I've been asked to simplify the captcha on my comments, so I have. :)I've been meaning to do it for some time, but though pure unadulterated laziness and other more pressing things to be done I just haven't got around to it before now.
To be honest though, I actually like the more complicated captcha and I'm happy to see them on people's blogs. No offense Charlie, but I'm not keen on the very plain captcha that your articles boil it down to, so I've rolled-my-own.
I've reversed the colours from the standard light on dark gradient, to dark text on plain light background. I've removed the ovals and the foreground lines, but left a reduced number of background lines and set their colour to "light".
I did want to increase the font size, but I noticed something strange. In the config xml file you can set the length of the random string. Now I kind of expected this to be a maximum number of characters that would appear, but I noticed that when it was set to 6 I was actually getting up to 7 letters in my captcha and now that its set to 5 I'm getting up to 6 letters. I don't know whether this is the way its supposed to be or if its a bug, but it was kind of annoying when I noticed a letter hanging off the edge of the graphic.
So anyway, I've reduced the number of letters to 5 in the config and increased the font by 5 points, which just about fits 6 letters in. If you happen to be unfortunate enough to get a 6 letter captcha that you can't read the last character of, please accept my apologies and try again, it shouldn't happen very often.
If you like the way my captcha looks, these are the changed config lines: