We develop a new technique to prove the faithfulness of the Hausdorff–Besicovitch dimension calculation of the family Φ(Q∗) of cylinders generated by Q∗-expansion of real numbers. All known sufficient conditions for the family Φ(Q∗) to be faithful for the Hausdorff–Besicovitch dimension calculation use different restrictions on entries q0k and q(s−1)k. We show that these restrictions are of purely technical nature and can be removed. Based on these new results, we study fine fractal properties of random variables with independent Q∗-digits.