It seems to be down. Sods Law - it was working fine when I posted the link this am. You can find it on goole with: wendy carlos retinex, but that link is down too.
Originally Posted by Ed Sukach
There are other retinex pages, but Wendy's are particularly good.
Bazzarely, retinex theory (discovered By Edwin Land of Polarioid fame) sugguests that in a situation like the sky image posted above, where the sky is predominantly red, is exactly the situation when you'd swear there wasn't any red to be seen!