No you have it wrong harden - the algorithms that se's use are complex - it makes it so you can't do what you are talking about. They want to take your text and figure out how many times you use the word Harden within your content - then they rank you and place you accordingly. So if you only have harden 5 times in an entire site you are going to have some competition:
http://www.google.com/search?q=Harda...ient=firefox-a
Besides - if you use css you can use display: none or visibility: hidden to completely hide your text- but it will still be there. But I am sure that the se probably void this stuff out because then you could use every word in existence to try to improve your rankings. I say re-think your total graphic idea.
--
Greg