1. Codices were used rather than scrolls
2. Terms like God, Lord, Jesus and Christ are always written as nomina sacra
3. The scribes were not calligraphers but document scribes who worked in their spare time for the community
He writes: "This development of a distinctive Christian scribal tradition which presumably goes back to the beginnings of Christian literature in the first century 'seems to indicate a degree of organisation, of conscious planning and uniformity of practice among the Christian communities which we have hitherto had little reason to suspect, and which throws a new light on the early history of the church.' The circumstances and customs in the church in the second half of the first century do not seem to me to been as diffuse and chaotic as people like to present them today."
Martin Hengel, Studies in the Gospel of Mark, 1985/2003, 79.
He quotes Roberts and Skeats, Birth of the Codex, 1983, 57.