Quote Originally Posted by ww12345 View Post
You have to make sure your films can be inspected under a safelight (I would say 90% of films today cannot). I'm sure others will correct me if I'm wrong, but it's my understanding that only ortho film can be inspected during development.
This is not correct.

The common thing to do is to use a very weak light of green color, and only for a very short period of time. Green is the color that the human eye is most sensitive to, which is the reason for using it.
A standard safelight is used, with a weak bulb, and you inspect the film from about 3-4 feet distance for a few seconds.
This does technically fog the film, but not enough to make a practical difference.

After much practice you learn what the film should look like, and you learn to gauge how much more development a negative needs before you pull it and put it in the stop bath.

Films like TMax 100 are difficult to gauge, because of the incorporated dyes that are used for sensitizing as well as filtering.