Other miscellaneous Epson 2200 comments:
Addendum, Epson Reply:
After two weeks, I finally got a close out reply from the Epson support center. Unfortunately, it did not clarify anything. In fact, they not only repeated all the previous guesses, they stated that the driver maps one image pixel to one printer dot so the best image resolution to use is 2880 PPI. I don’t think some of their folks understand printers. In fact, they seem fascinated with the concept of indoor plumbing. In spite of this, Epson does make excellent inkjet printers.
Since Epson seems to constantly reference the following: “R. Floyd and L. Steinberg, An adaptive algorithm for spatial grey scale, Proc. Soc. Information Display, Vol 17, p. 75 (1976)”, I will take a moment to address it. First, note that this article is almost 30 years old. It was certainly novel at its time and an important contribution to printing technology. But, it is out of print and I have been unable to obtain a copy of the original text. The article describes “error diffusion” as a way to improve the quality of two-tone images using the low-resolution printers of the time. These algorithms and the technique are described in many current articles, hundreds of which suggest improvements to reduce undesirable artifacts of the original algorithms.
Error diffusion spreads the difference between the tone desired at a point and the capability of the ink (error) to neighboring points in the image (diffusion). Though it can improve visual quality of most low-resolution prints, it can introduce artifacts. It is also computationally intensive and does not easily exploit parallel processing. It can be utilized with color images, but the computations for each available color need to be done independently.
There are many additional techniques such as variable dot sizes, stochastic dithering, and the use of different cell array angles (screen angles) for different colors that can also improve image quality. Naturally, having more ink colors to select from provides the most significant improvement. Naturally there are dyes, pigments, and ink delivery techniques that all have individual merits.
None of these techniques are applied to the image pixels. The image must be mapped into the printer elements (pels, cells, or dots) before any of this magic can be employed. So once again, Epson has avoided the question. Worse yet, they have insulted my intelligence and forced me to do a lot of frustrating and unnecessary research.
The 5x5 cell size fits logically and it produces the most consistently matched image to printer resolution. 288 PPI. That’s my story and I’m sticking to it.
Rags Int., Inc.
204 Trailwood Drive
Euless, TX 76039
April 19, 2004
This page last updated on: Thursday April 12 2007