A few days after my first film developing at home, I found out I severely underdeveloped it. For some reason, I thought 6 minutes was the proper time, I really have no idea where I got that info, and today I was studying some Kodak charts and saw the time (for Kodak D76 and Tri X 400 using 1:1 solution) should be almost 10 minutes. 4 minutes difference! How do you find out a film is underdeveloped? I thought mine was underexposed, but developed fine until today. Can you see the difference between underexposed and underdeveloped negative? Also, the Kodak recommends agitating every 30 seconds, in a small tank like mine, but my friend teacher taught me only to agitate every minute. What difference does that make on the final negative? Thanks.