The need for a color test object that guides the basic color correction adjustments of the electronic color separation scanner provides the starting point for this paper. The scope of this need, including differences in original photographic color materials, different process ink colorants and differences in the red, green, and blue responses of the various color scanners will be identified as variables. A three-element color test object evolved from a detailed analysis of this need: A "selective" neutral scale based on visual perception step-to-step differences, a neutral scale plus corresponding cyan, magenta, yellow, red, green, blue dye scales, and a set of 120 color patches (10 variations in lightness and saturation for 12 different hues) which cover the color space of the color material.

The high-definition color laser plotter CLP-300 was developed with the main purpose of using digital color' image data to create color originals for printing reproduction use on color photographic materials. It uses three, laser light sources: argon ion (AO, green helium-neon (green He-Ne) and helium-neon (He-Ne), to continuously' modulate beams of blue, green and red light in response to image data, simultaneously scan-exposing each photosensitive layer of the color photographic materials at a maximum resolution of 80 lines/mm and a maximum. speed of 1200 lines/minute, thereby recording a continuous tone color image on the photographic materials. Through the use of a green He- He laser, this unit is able to use light wavelengths that more closely match the color sensitivity of photographic materials and can therefore provide a wide gamut of reproducible colors. In addition, the CLP-300 can also perform color and gradation conversion, basically using a look-up table method for both, in order to change either 4-color YMCK image data for printing reproduction use or computer graphics and other 3-color BGR image data into the 3-color YMC image data for color photographic materials, thereby achieving superior color and tone reproduction.

Random laser-writer position errors in raster-scanned monochrome halftone images and the effects of non-uniformities in the recording medium are examined using Fourier analysis techniques. For a high contrast, narrow-exposure latitude recording material (typically used in halftone reproduction) with medium-sized halftone dots (25-85%), a one-dimensional halftone model is developed to derive the signal power spectrum of a halftone image containing position errors in the slow-scan (page-scan) direction. Non-uniformity in the recording medium (via sensitivity or reflectance) is modelled by representing the digital halftone image as a random amplitude-modulated signal. The spectrum of an image containing these combined effects is shown to consist of a periodic component and a random component, which is a function of position error but independent of dot size. The term signal power spectrum, in the context of this work, is the average modulus squared of the Fourier transform of an image containing these errors. The results can be generalized to include any digitally generated halftone image based on a center-growing dot configuration and containing dot size/shape distortions.

In the graphic arts industry, a digital image is stored as four continuous tone files of Cyan, Magenta, Yellow, and Black (CMYK). These are the most common colors used in a 4-color ink printing process. Since a printing press cannot print "differential" amounts of ink at a given location, printers achieve fine tonal gradations by printing halftone dots of smoothly changing "areas". A screening computer's primary function is to convert these continuous tone pixel values into halftone dots. In general, the task of transforming continuous tone pixel values into halftone dots is computationally intensive. Furthermore, when using a high resolution output writer, screened halftone bitmapped images can easily exceed 100 Mbytes per separation, resulting in lengthy and unacceptable screening times. As a result, the sheer volume of data that must be manipulated in the screening process dictates the need for a high performance, special purpose screening engine, which does not degrade the performance of the target system. This paper first introduces the fundamental theory and concepts of electronic digital halftone screening. Second, a set of fundamental functional requirements for a digital screening computer are developed. Third, a parallel, pipelined screening computer design, which meets the developed functional requirements, is presented. Last, an illustration of digitally screened halftone dots is provided.

Both high speed and unmatched resolution are available with an Electron Beam Recorder (EBR). An EBR uses a beam of electrons to expose silver halide film, processless recording media, and other sensitized materials. The EBR can be used to record or plot graphic arts quality text, line art, and graphics products from digital data from raster, vector, halftone, and/or typeset databases. Applications for the EBR in the graphic arts range from a very high speed, high resolution typesetter to an output recorder for page make up systems. With an EBR as an output device page make up is much easier because both vector and raster recording can be utilized on each page as required. This allows the recording of complete reduced size flats ("miniflats") directly from digital data at recording rates in excess of 25 megabits/sec and a resolution of 4 microns.

Good morning ladies and gentlemen. I represent Polaroid Graphics Imaging, a wholly owned subsidiary of the Polaroid Corporation. We wish to thank Ken Cloud and the SPIE for the opportunity to speak today. Several criterion are fundamental in the role for Direct Digital Color Proofing (DDCP), First, the DDCP must represent a first generation hardcopy of the exact color information in the production stream. If must, as it's name suggests be an exact, proof (hence the name direct) of the electronic or digital information which would otherwise be directed toward film working. It is after all the most critical means to evaluate the quality of whatever pagination, scanner or color work which has gone be for it. Second, the DDCP must represent an opportunity. That opportunity is to reconvene the production stream and move to film making, optical or magnetic storage, or satellite transmission with the confidence that the DDCP is identical to some conventional counterpart. In the case of film it must match a conventional proof and press sheet, dot for dot. Otherwise it is merely an exercise in interpretation. For magnetic or optical storage and satellite transmission there must be assurance that at any opportunity either a duplicate DDCP or a conventional film/proof could reproduce earlier results. Finally as the printed product is the final goal and direct to press is evolving in direct to plate and direct to gravure printing the DDCP must share the half toner lineage of these products. Thirdly and hardly least, the whole purpose for DDCP is increased productivity. However, our industry struggles to maintain individuality and variety. Somehow DDCP must balance these forces.

For the past few years, Stork Colorproofing B.V. has been marketing an analog color proofing system in Europe based on electrophoto-graphic technology it pioneered for the purpose of high resolution, high fidelity color imaging in the field of the Graphic Arts. Based in part on this technology, it will make available on a commercial basis a digital color proofing system in 1989. Proofs from both machines will provide an exact reference for the user and will look, feel, and behave in a reproduction sense like the printed press sheet.

IRIS Graphics, Inc., is a new start-up company chartered to develop, manufacture, and market direct digital filmless color imaging systems. IRIS is pleased to have been the recipient of the Graphic Art Technologies Foundation INTERTEC '87 Award for innovative excellence. IRIS is extremely proud to have been given this honor. IRIS was incorporated in April 1984 and received its initial funding of approximately $1 million by September 1984. The first 2044 Beta unit was installed in August 1985, and the first 2044 sales were made in December 1985 to R. R. Donnelley, the largest printer in the United States, and to G. S. Litho, the largest U.S. color separation house. In May 1986, IRIS received an additional $3 million in its second round of financing. A smaller version of the 2044, the 2024 was introduced at Lasers In Graphics in September 1986. IRIS achieved additional financing in July 1987 and completed the introduction of the new breakthrough Series 3000 again at Lasers In Graphics in September 1987 in Orlando, Florida. IRIS occupies 20,000 square feet at its new location in Bedford, Massachusetts, which located off of Route 128 in the high technology area near Boston.

The 4 CAST^tm Digital Color Imager by Du Pont is the first application of thermal dye sublimation transfer technology as a graphic arts pre-press proofing system. This unique technology, also referred to as dye diffusion thermal transfer, offers a number of distinct advantages over other processes used to produce digital color hard copy.

For the sake of clarity, two fundamental questions should first be addressed: "WHAT IS SOFTPROOFING AND WHY WOULD ONE WANT TO SOFTPROOF?" Softproofing is just another off-press proof for verification and approval of color and its corrections. Proofing is done on an image presented on an imaging display and is called a "soft" image because it disappears when turning off the display. The major purpose of soft proofing is to significantly decrease turnaround time in the color approval process. Although soft proofing ,in all likelihood, will not replace other color proofs completely, it offers an important contribution to to increased productivity in the Graphic Arts Industry. It should be obvious to all off us that this technology will only prove useful if the soft image is a true representation of the final proof on which the customer will sign off to provide the binding contract between the customer and color separator. Essential factors for a match between the soft image and a hard copy proof--whether it be photomechanical proofs, such as transparencies, digital proofs or press proofs--are numerous and complex. Probably the most important requisite for any proofing system is CONSISTENCY. Color consistency in the display over time (from day to day), over space (from shop to shop, machine to machine), and over image content. Undoubtedly this is what kept a lot of you from using softproof techniques heretofore. Before describing what problems in traditional displays keep you from achieving consistency and thus use soft proof techniques, it may be worth pausing here to examine and get a better understanding of the transfer curve of a display. (see fig 1) The graph represents the light output for the three colors and the

Spatial uniformity of high resolution laser writer copy is analyzed using PC-based image processing techniques. These techniques are shown to provide a simple characterization of the laser writer through its output copy.

The aim of this project is to produce a high-resolution, colorimetric and permanent digital archive of images taken directly from works of art. The proposed system is designed for use in education, research, galleries and museums. Tentative user requirements are examined with particular reference to resolution, image access and colorimetry. Existing technology and projects are considered. Some 3000x3000 pel images of paintings are used to illustrate the interrelationship between dimensions of the original, its inherent detail, scan resolution and display.

Research institutes, industrial companies, computer animation studios and printing facilities are often equipped with a lot of different machines for the rendering and display of raster pictures. The output devices (monitors, recording devices, printers) differ in their geometric and color resolution, in the picture format, and in the chromaticity of the color primaries. There is a need to transfer pictures via local networks (LAN) from one device to another at studios and laboratories without having to compromise for the quality of the pictures. And there is a need to transfer pictures via tape, floppy or networks (WAN) from one institute to another, or from an institute to the publisher, and so forth. For these purposes, a special format for the transfer of raster pictures has been developed which is independent of differences in pixel resolution, color resolution, color primaries, number of colors per device, and scan direction. For its use in the networks and on tapes, the file format has to initially have a character encoding to prevent any collision of pixel or image data with control sequences of terminal servers, network controllers, and other hardware devices. Binary encodings are still to be developed; the format is open for different data compressions and other data encodings according to different application profiles. The format is called FTCRP - File for the Transfer of Colored Raster Pictures. Historically, a Version 0 of FTCRP was first developed. Several insights were gained in the imple-mentation of FTCRP driver programs and in the acceptance of the new format. Here, we present the conception of Version 1 of FTCRP, which is an extension and an enhancement of the former version. Unfortunately, the syntax of FTCRP Version 1 was not definitivly determined before the submission of this text. Therefore we concentrate on conceptual considerations. This paper is intended to encourage further discussion and refinements.

The standardization of the interchange of color pictures between color electronic prepress systems (CEPS) and CEPS related systems or components, has been accomplished with the ratification of Digital Data Exchange Standard (DDES). Now UEF01 for the exchange of line art data is also an ANSI Standard, and User Exchange Format (UEF00). Work is nearing completion on three other fronts with formats for Geometric Art files, device exchange standards for a digital color proofing systems, and monotone image formats. These standards and other standards coordination efforts, assisted by the formation of the Committee for Graphic Arts Technical Standards (CGATS), should help tie the fragmented graphic arts industry together and improve its overall productivity.