Originally Posted by arzon
Freshly-mixed ID-11 always "looks like piss" so it should be perfectly useable. I've used ID-11 when it has darkened by oxygen exposure to a golden brown colour and still had good results. To get a rough idea you can cut off a small strip of 35mm leader, fog it and drop it into a receptacle containing the developed you want to test. If it turns black within the time stated on the developer chart it should be good to go. The only way you'll know for sure is to develop an unimportant film with it and see what happens.