Hard Edge Solution for Digital Proofing

Digital proofing technology is getting wider use nowadays, particularly in the direct to plate workflow where it is necessary. Comparing digital proofing output to that of analog proofing, such as AgfaProof, contone quality decent, even at 300 dpi. However, digital proofs lack the sharp (hard) edges necessary for text and line art. In order to obtain acceptable hard edge quality, higher resolution digital proofing devices such as a 2400 dpi printer, are required. However, for the RIP twice scenario, 2400 dpi pages have 64 times more data than 300 dpi to store and pass through network. It is not practical at all in implementation. In this paper, we proposed a PostScript hard edge solution to compress a 2400 dpi page to the data size comparable to that of 300 dpi. By applying it to a high resolution digital proofing device, this PostScript hard edge solution can support a proof quality as good as the same resolution analog proof but with a data size of at most 1/64. The performance of the implementation is linear related to that of the corresponding Run Length Encoding and file saving.