Cause:

Finger allowed to slip or twist during printing, or excessive perspiration on finger, or excessively dry fingers or worn ridge structure from work (e.g., masonry, carpentry, etc.) or physiological conditions (e.g., low level of perspiration).

Solutions:

To prevent slipping or twisting, always maintain control of the finger and hand of the individual being fingerprinted.  Individual should try to relax and not attempt to help in the inking and rolling process.

Remove excess perspiration from each finger immediately prior to inking; dry, ink and print one finger at a time.

Consider using a drying agent (e.g., alcohol) to temporarily slow the rate of perspiration.

For excessively dry fingers consider using a softening or moisturizing agent such as hand lotion or oil.