Opened vs open?

Is there are rule when to use opened vs open? I always get confused even though I've been speaking English as the dominant language for more than half my life.

E.g.

• Is the door open(ed)?
• Which file do you have open(ed) in your editor?

The word open can be an adjective describing the door, or it could be a verb, which can be in the past, future, or present tense. Open in your first example is an adjective meaning "not closed or blocked up." (There are other meanings to open as well.)

The same pertains to the second example. Someone has a file that is open, not closed.

If you did the action of opening the door (or file), then you opened it. If the door opened itself, you can say, "The door opened." Or, you could run away. I'm pretty sure that's the right move, based on what happens to people in films who stick around after a door opens itself.

_{Under open, Merriam-Webster uses the example to illustrate being in a position or adjustment to permit passage: not shut or locked.}

1. The door is open. ("open" is used here as an adjective. It means it is not closed)
2. The door was opened by Mark. ("opened" is used here as a passive form of verb. Mark did the work)
3. The door is closed. ("closed" is used here as an adjective. It means it is not open. It doesn't matter if it was closed by itself or Mark closed it, the word should be "closed")
4. The door was closed by Mark. ("closed" is used here as a passive form of verb. Mark did the work.)

I hope it clarifies.

Open does not refer to any past event, while opened does. Both refer to the same current state, but opened opens the door to an earlier narrative, if you will. The door was once closed*, and someone or something changed it. The use of opened indicates a larger history for the object that open entirely ignores.

*interestingly there is no aorist form of closed

To get briefly technical, open can be considered the aorist aspect and opened as the perfect aspect. (In actuality open is an adjective, not a verb, and English doesn't use the aorist. Nonetheless, I find the aspects interesting and useful.)

Aorist is a past verb form that does not refer to "duration or completion" (NOAD). It can be considered as ignoring the verb-ness of the verb, if we consider the verb the action.

Perfect, on the other hand, is a past form that emphasizes the completion. The verb happened. The use of the perfect does not always specify when the action took place, but we know that it did.

Another example of this divide is complex (aorist) versus complicated (perfect). Here, complex describes the essence of the object, while complicated describes its condition. The object was not always complicated, but has become so: some actor complicated it. The difference of essence or condition can also be analogized to the Spanish ser (essence) and estar (condition), if that helps.