Final answer:
The three main principles used in handwriting examination are observing regular patterns, identifying unique characteristics, and performing comparative analysis to establish consistencies or differences between writing samples.
Step-by-step explanation:
The three main principles used in handwriting examination and comparison are:
Regular Patterns: Examiners look for consistent features in the writing samples such as the slant, height, and spacing of letters. The use of interlines and a baseline, as described in the case of the Kufic family of styles, indicates a habitual formation of letters and a disciplined creation of consistent, repeating patterns.
Unique Characteristics: While looking for regular patterns, experts also identify the unique aspects of a person's handwriting. These could include specific ways of making letter strokes or unusual letter formations, reminiscent of how artists use various techniques to create distinctive forms of visual expression.
Comparative Analysis: Each individual's handwriting is compared to a known sample for similarities and differences. Much in the way art historians analyze and discuss the use of design principles like balance and repetition in artwork, handwriting examiners compare aspects like pattern, texture, and rhythm in samples.