a. The study of ancient writing and inscriptions; the science or art of deciphering and interpreting historical manuscripts and writing systems.
Basic Rules of Hebrew Palaeography
8. The stylistic changes are caused by a variety of factors, of which the following are most important: time and place, the writing materials and implements, the speed of writing, and the influence of imitation of other scripts.
a. Time. A script, like a language, changes in the course of time, even when a tradition is strictly followed. A minimal change may develop a dynamic of its own and gather momentum in a certain direction, thus influencing the evolution of the script. Sometimes a change in the letterforms is temporary, leaving no trace in the script's subsequent development, as in the case of the idiosyncrasy of a certain scribe. Changes that become systematic are, as we said, stylistic changes. One of the major changes in a script - one which develops slowly - is the change in the relative size of the letters of the alphabet. Thus, for example, there is a difference in the relative size of the letter-signs in the script of the early scroll fragments from Qumran and the script used in manuscripts two centuries later (quite apart from other formal changes in the script). Rapid changes in the letter-forms are generally due to fluent writing with ink. Scripts of different degrees of cursiveness may sometimes be used for different purposes, such as writing official documents as against private letters. Script-styles constantly change and the situation is never static.
b. The nature of writing materials and writing implements. Letters of one and the same script-style will have different appearances when written with different instruments on different surfaces. There is a difference between writing in ink on a soft surface and inscribing letters on a hard material. The writing implement, whether a brush, or a reed-pen, a quill, a chisel, etc., and the way the implement is cut and held, also influence the form of the letters. A careful examination of their inner structure will reveal the common features of the letter-forms. On the other hand, the use of different implements and materials can result in formal changes in the script which can become stylistic. Thus, for example, it is difficult to draw horizontal strokes from right to left or vertical strokes in an upward direction with a flat writing implement held in the right hand, while such strokes are easily made with a sharp or round writing implement. A flat pen, unlike a sharp or round pen, can be used for writing letters with thick and thin strokes and ornaments, which may become stylistic features of that particular script.
c. The speed of writing. Writing on soft surfaces, unlike writing on a hard material, usually encourages flowing movements which may cause rapid changes in the form of the letters. Already in ancient times, a reed-pen or brush was used for writing in ink. As a result of this fluent writing, the forms of the letter-strokes as well as their meeting points and the forms of their joints underwent fundamental changes. The lapidary script usually continues to exist together with the cursive hands and there was a mutual influence on their letter-forms; cursive found their way into the lapidary script and vice versa. This process gave rise to a large variety of letter-forms of different degrees of cursiveness, and cursive and semi-cursive script-styles emerged which were sometimes used concurrently for different purposes.
d. The geographical factor and the influence of imitation of other scripts. The Jewish script, and later the Hebrew script, evolved many styles due to contact with foreign scripts. Already before the dispersion of the Jews throughout the world, the Jewish script came into contact with the Greek and Latin scripts as well as the Nabatean script. In later times many new script-styles evolved among the Jewish communities in the different countries, with the influence of the foreign scripts as well as the use of different writing implements and materials. The changes in the letter-forms were sometimes due to deliberate imitation and they sometimes occurred unintentionally, mainly because the continual use of foreign scripts together with the Hebrew script occasionally caused changes in the hand-movement of bilingual scribes. Thus the Hebrew scripts in the Islamic countries show affinities with the Arabic script while the Hebrew scripts in Christian Europe show affinities with the Latin script-styles used in the different countries.
The more strict the scribal tradition was, the less recognizable were the changes. Thus, for instance, in the calligraphic square Hebrew script which was used for the writing of sacred texts from the 9th century onwards, minimal changes occurred in the course of times, while the cursive and semi-cursive script-styles, which evolved at about the same time, show considerable changes in the form of the letter-signs. However, even the calligraphic square scripts used for sacred purposes underwent stylistic changes. Thus the number of ornamental additions increased as well as the variety of letter-f0rms of the joints between the letter strokes.
Ada Yardeni, The Book of Hebrew Script: History, Palaeography, Script Styles, Calligraphy & Design, 2002, pp. 139-143.