In order to appreciate the shift from handwriting to printing, you need to carefully examine how the manuscript characters developed and were used. The learning and use of the characters were a formal process requiring a lot of training and discipline in order to produce a writing in a specific style.
The western European languages derive their common alphabet from the Romans, who developed the characters to represent the Latin language on the model of the Greek characters (which, in turn, were a descendant from the Semitic alphabets, such as the Jewish alphabet) in order to create a separate system of writing. The Roman alphabet was used for a wide range of situations, for literary purposes and documentaries, but also for inscriptions on monuments and graffitis:
With the end of the Western Roman Empire, many new states arose and in the areas that in the past were part of the Empire people continued to use the Latin alphabet, as well as the Latin language, of course. However, in the areas outside the borders of the Empire, the use of the Roman alphabet until after the end of the Empire is attested sporadically. In these areas, as well as in some others where the Latinized population had been greatly affected by waves of immigration from outside the Empire (such as in Britain), the Latin alphabet was introduced, or reintroduced, by the Christian missionaries during the first millennium b.C.
The Latin alphabet introduced in the Anglo-Saxon England of the first period together with the Christians seems to have included both uppercase and lowercase letters. In Latin scripts, they were used for various purposes, uppercase letters for inscriptions and lowercase letters for handwriting. At the beginning of the Middle Ages, we begin to see the combination of uppercase and lowercase forms in handwritten documents, where the uppercase letters were used to indicate textual features such as the beginning of the sections. This is the point that marks the beginning of the use of uppercase letters to indicate the start of the phrases that is currently the norm of the modern European languages. However, it is worth noting that the scribes of the early medieval period did not use punctuation in the same way we do, and did not use uppercase letters exactly at all points of the writings where we would use today.
Over the following centuries of the Middle Ages, the characters in use in England changed their shape. The Latin alphabet shapes developed in Great Britain and Ireland in the early Middle Ages were quite different from the Roman alphabet varieties used on the continent. This applies especially to the insular lowercase character, that is the one mainly used in the Old English texts.
Along with the insular lowercase, the Anglo-Saxons also used the uncial character, that is, an uppercase character, in addition to developing a hybrid character with mixed characteristics of both the insular lowercase and the uncial, known as a half-uncial. The uncial and half-uncial characters are easily recognizable by the large and almost circular holes, for example in O, P, etc. The fundamental distinction between the two characters lies in the shapes of the letters, in what the half-uncial shares with the insular lowercase, but there are also letters like e and n that tend to appear in the uppercase form in uncial, but in lowercase in the half-uncial.
The insular lowercase itself can, in turn, be divided into a number of varieties. The distinctive features of all types of insular lowercase consist in a certain number of letters that are not found in the continental characters. In the example of half-uncial shown above we can see how between the lines there are some small letters: these are the English glosses to the Latin text written in a variety of insular lowercase. The red labels in the image indicate some features of the insular lowercase.
Most notable is the form of the long s, which has an insular lowercase descending line, while in the continental character the letter remains above the line and stands at the top. Even the letter eth is very peculiar: it is a modified form of d developed in the Anglo-Saxon England to represent the sound now indicated by the sequence th. Of course, this letter was not used when they employed the insular lowercase for the Latin script instead of the English script. Towards the end of the Anglo-Saxon period, however, they began to use the Carolingian minuscule used in the Frankish Empire to write Latin documents in England, where the insular lowercase was usually still used for texts in English. For today’s readers, the Carolingian minuscule is more readable, since the shapes of the letters are very similar to the modern ones.