Back around 1987, I used a Macintosh 512K computer, a monochrome CCTV camera, and an Imagewriter II dot matrix printer to produce digital color prints. The resolution was 1-bit 512 X 512. The Mac graphics card outputed 1 bit pixels--either black or white. I'd stack the R,G,B,K files so the printer spit out C,Y,M,K. I guess that you could say that this process produced files consisting of 4-bit pixels, once the files were stacked. Looking back, I'd say this was "Fred Flinstone" color technology. I got pretty good at knowing what f/stop to take each of the exposures at. The resolution was so low that I didn't have to worry much about depth-of-field. Also, the CCD sensor in the camera was microscopic, so DOF didn't really matter. I printed the images onto archival paper. They still look great. Frankly, I only see your IQ260 Achromatic tests with R,G,B filters as being an academic execise. If you really want ultra-high resolution color, use a multi-shot system.