Emphasis

-지가 않다 (Subject Negation)

Used to emphasize the subject's personal experience or involvement in the negation of an action or state.

Usually used with adjectives.

-지는 않다 (Contrastive Negation)

Used to form a negative sentence, emphasizing the contrast or the unexpected nature of the action or state being negated.

Can be shortened to the form -진 않다.

-지를 않다 (Broad Negation)

Used to emphasize the negation of an action or state.

Can be shortened to the form -질 않다.

Usually used with action verbs.

-지도 않다 (Emphatic Negation)

Used to emphasize that an action or state does not occur or is not done. It adds an extra layer of emphasis to the negation.

-지만 않다 (Conditional Negation)

Used to indicate that while something may not happen or be the case, it leaves open the possibility that something else might. It often implies "as long as" or "as far as."

It's possible to add the 은/는 to -지만 않다 to form -지만은 않다.

Shortened form

With 하다 verbs, 하지 않다 can be shortened to 치 않다. Specifically after voiced support consonants such as ㄴ; ㅇ; ㅁ; ㄹ.

Type	Full form	Shortened form
1	피곤하지 않다	피곤치 않다
1	확실하지 않다	확실치 않다
1	금하지 않다	금치 않다
2	공부하지 않다	--
2	익숙하지 않다	--
2	섭섭하지 않다	--

This shortened form also applies to other negated grammar such as 지 못하다 and 지 말다.