I agree with dj.
This has to be demonstrated and heard. It is not really a matter of "touch" but of the "effect". It does not matter which technique (movement, touch, etc.) you use, but rather that you obtain the effect. So first you must get used to the effect (that is, the sound), then you keep changing your way of playing until you get it.
You have two options:
i. As dj said, ask for someone knowledgeable to demonstrate it for you (=teacher)
ii. Listen to a CD/performance of the piece you are interested in by a pianist who believes in authenticity (e.g. Brendel, Tureck) and avoid the pianists that are into a"personal" interpretation (e.g. Pletnev, Pogorelich).
Please do no misunderstand me: Avoid "personal pianists" only for the didactical purpose of getting the authentic sound effect. The "personal" pianists are often the most interesting and not to be avoided in any other circumstaces.
Best wishes,
Bernhard.