Are they the stick ones...? You know what, I've been wondering about this for a while too. The OPKs I'm using actually say (I've just ran to the bathroom to get the bit of paper!) -"If two colour bands are visible and the test band is of ALMOST equal or greater colour intensity.....this is a positive result" - so,I think firstly and foremostly, a progression is of most importance- so if you control for a few simple factors, like how dilute/concentrated your pee is, and what time you test, then you can see your personal progression and trust it. Then, if you can see an OBVIOUS faint-less faint-darker-almost as dark-fainter again pattern, then it probably doesn't matter that it's not actually AS dark- especially when coupled with all your other symptoms of ovulation. After all ,what on earth would the darkening mean if not ovulation, even if it's a shade lighter than the control line? They're not so amazingly sensitive that they go up in actual increments of LH, just a few variable stages that 'correspond' - i.e. faint=not ovulating, less faint=closer to ovulation, dark= ovulating (etc) Sorry about this ramble, I wanted to ramble it somewhere and since you asked a related question, you got my long answer! so the short one would be- I think yours is very likely positive.