One of our works in ISO/TC13O WG3 is to analyze the colorimetric characteristics of process color prints produced under the JAPAN COLOR condition. At first, we provide the computed values of Color Reference patches on offset color proof prints with CIELAB color coordinate. By using these values, we have studied the color coordinate conversion method from CIELAB to CMY dot percent values. The results studied are depicted in this report.
Former multilevel error diffusion method having 3-8 quantization. This paper shows that the lack of AC components around quantization signal levels deteriorates image rusolution and causes low image quality. Then, it proposes a new method, which has a layered structure and supplements AC components properly by modifying error diffusion process. Consequently, it presents high quality multilevel dithered images.
We are investigating the melt-type thermal transfer printing by laser heating. The laser diode irradiation is absorbed as heat in the thermal transfer ribbon which results in local melting and transfer of the ink to the receiving sheet. A high definition image with the resolution of 2,540 dpi was obtained. In this paper, recording energy, speed and the shape of printed pizel are discussed.
In recent years, many full-color printers using various printing methods, have been produced. It is important to establish a quantative method to evaluate image qualities of such printing systems. However, there are few papers that evaluates image structure of various hardcopy outputs by scanning exposure. To accomplish them, we improved measuring accuracy of a microdensitometer, and compared potentiality of those printing systems in a view of image structure.