I have done an experiment and I want to write two articles about it. It has a main data and figure ( The optimum dose and time). Is it possible to use the main figure in two different articles? Isn't it self plagiarism?
If you created the original, you can use it with a citation/reference to the first publication.
You should not reproduce someone else's figure without permission, even if you provide a reference. Create your own (that is not too similar to the original) to convey the same information.
If you cite yourself as the source it is not self-plagiarism. Some peer reviewers do not like self-citation. I think that a few relevant self-citations are OK, but be sure to base your work on many other authors and references as well.
If it is for the same purpose it is not possible. Because it means pligarisam even if you are the author. If it is for the different purpose it may be good . You are the best judge to use or not to use
Yes, you can use the same figure in the 2nd article which you've already used in the previous one. But, make sure that you'll put thta in reference clearly.