text:  The Ming dynasty had seen considerable advancement in the process of colour printing in China . At his studio , Hu <unk> experimented with various forms of <unk> printing , creating processes for producing multi @-@ coloured prints and <unk> printed designs . As a result , he was able to produce some of China 's first printed publications in colour , using a block printing technique known as " <unk> block printing " ( <unk> <unk> , <unk> ) . This system made use of multiple blocks , each carved with a different part of the final image and each bearing a different colour . It was a lengthy , <unk> process , requiring thirty to fifty engraved printing blocks and up to seventy <unk> and impressions to create a single image . Hu also employed a related form of multiple @-@ block printing called " set @-@ block printing " ( <unk> <unk> , <unk> ) , which had existed since the Yuan period some 200 years earlier but had only recently come into fashion again . He refined these block printing techniques by developing a process for <unk> some of the ink off the blocks before printing ; this enabled him to achieve <unk> and <unk> of shades which were not previously possible . 
  