Complex sentence: During the metal type era, all type was cut in metal so could only be printed at a specific size, and it was a natural process to vary a design at different sizes, making it chunkier and clearer to read at smaller sizes.
Split into simpler sentences: During the metal type era, all type was cut in metal and could only be printed at a specific size. It was a natural process to vary a design at different sizes, making it chunkier and clearer to read at smaller sizes.