The arrival of the information super highway has introduced a number of problems, both for the owners of copyrighted images and for those who would like to legitimately use those images. The digitization of all content, whether still image, animation, video, music, or text, has made copying infinitely easier and cheaper. Further, the instantaneous access to this wealth of digital copyrighted material by millions of potential users, and would-be pirates, has the potential to greatly proliferate the number of unauthorized copies being made. For most of this century, technology has facilitated the unauthorized, and thus uncompensated, use of copyrighted material. Thus, xerography, audio and video recording systems, and personal computers have all contributed to the problem. However, we are entering a new era, where encryption techniques will not only prevent unauthorized use of copyrighted material but facilitate the use of that material by those that are willing to pay a commercially reasonable fee for such use. The technology, referred to as 'information metering,' allows usage fees to be based on a variety of use parameters. Thus, the material can either be 'rented' for a single use or a fixed number of uses, or it can be 'purchased' for an unlimited number of future uses. One price can be charged for on-screen viewing, with a higher price for hard copy print-out. In the case of digital images, the browsing function can be free, while the price of the print-out function can be based on the resolution of the image.

During the last 5 years, digital techniques have become extremely important in the graphic arts industry. All sections in the production flow for producing multicolor printed products - prepress, printing and postpress - are influenced by digitalization, in an evolutionary and revolutionary way. New equipment and network techniques bring all the sections closer together. The focus is put on high-quality multicolor printing, together with high productivity. Conventional offset printing technology is compared with the leading nonimpact printing technologies. Computer to press is contrasted with computer to print techniques. The newest available digital multicolor presses are described - the direct imaging offset printing press from HEIDELBERG with new laser imaging technique as well as the INDIGO and XEIKON presses based on electrophotography. Regarding technical specifications, economic calculations and print quality, it is worked out that each technique has its own market segments. An outlook is given for future computer to press techniques and the potential of nonimpact printing technologies for advanced high-speed multicolor computer to print equipment. Synergy effects from the NIP-technologies to the conventional printing technologies and vice versa are possible for building up innovative new products, for example hybrid printing systems. It is also shown that there is potential for improving the print quality, based on special screening algorithms, and a higher number of grey levels per pixel by using NIP-technologies. As an intermediate step in digitalization of the production flow, but also as an economical solution computer to plate equipment is described. By producing printed products totally in a digital way, digital color proofing as well as color management systems are needed. The newest high-tech equipment using NIP-technologies for producing proofs is explained. All in all it is shown that the state of the art in digital multicolor printing has reached a very high level in technology, productivity and quality, but that there is still space for improvements and innovations. Manufacturers of equipment and producers of printed products can take part in a successful evolution-changes, chances and challenges must be recognized and considered for future orientated activities and investments.

Technologies such as Xeikon, Indigo, and the Heidelberg/Presstek GTO-DI can change both the way print buyers may purchase printed material and the way printers and trade services respond to changing demands. Our recent study surveys the graphic arts industry for their current views of these new products and provides forecasts of installations and usage with breakdowns by market segment and size of firm. The acceptance of desktop publishing and electronic prepress have not only paved the way for a totally electronic printing process, but it has broadened the base of people who develop color originals for reproduction. Electronic printing adds the ability to customize jobs on the fly. How print providers will respond to the impact of electronic color printing depends on how each firm perceives the 'threat.' Most printing companies are run by entrepreneurial individuals who have, as their highest priority, their own economic survival. Service bureaus are already looking at electronic color printing as yet another way to differentiate their businesses. The study was based on a mail survey with 682 responses from graphic arts firms, interviews with printers, suppliers, associations and industry executives, and detailed secondary research. Results of a new survey in progress in January 1995 is also presented.

The desire to print high quality, highlight color documents at production rates has brought on the need for a single-pass highlight color laser scanner. We examine a pulsed-imaging, pulse-width-modulated polygon laser scanner that enables multilevel exposure and subsequent development of black and highlight color toner. As currently used in the Xerox 4850 digital printer, this scanner writes three different exposure levels; no exposure, mid-level exposure and high exposure for black, white, and highlight color, respectively. In this paper we review the functioning of a pulsed-imaging scanner and then examine how it is used in a pulse-width-modulated trilevel mode. A linear-systems model is used to examine the specialized video required for achieving uniform line appearance for both black and highlight color. This model further describes how image enhancement is enabled. A complete laser/xerographic model is used to simulate the output.

Texas Instruments has pursued the development of a Spatial Light Modulator called the Digital Micromirror Device (DMD) for a number of years. The device is applicable in both display and hard copy applications. This paper discusses the progress that has been made on a DMD imaging subsystem for high speed, high quality electrophotographic printing. An architecture and method of manufacture have been developed for a monolithic silicon area array DMD suitable for imaging across an A3 page (297 mm) at 600 dots per inch. The device and optical characteristics will be discussed in the context of an experimental testbed.

Cartridge remanufacturing is reaching a turning point. Although more cartridges are being remanufactured today than las year, profitability is not as many would like. Margins for SX-type cartridges are slim. In addition, penetrating the LBP-NX and LBP-EX business has been slower than was expected. Although BIS expects that remanufacturing will rebound, the state of the industry today exhibits the signs of being in a slump.

The ion-jet printing method controls the ion flow directly to make an electrostatic latent image on an insulated layer. This printing method has several advantages over laser printing, such as high printing speed and simple maintenance. However, conventional ion-jet method poses a problem, particularly for office printer applications, because a high- voltage circuit is required to control the ion flow. We developed the new ion-jet printing method to solve this problem. The new process uses a precharge to accelerate the ion flow to the insulated layer, and the high-voltage bias is eliminated from the head. So, the new ion-jet head permits controlling the ion flow by a low-voltage signal. Experimentally, we attained a printing speed of 20 ppm and a resolution of 400 dpi at the control voltage of -30 V, and succeeded in printing Chinese characters with 32 X 32 dots per 2 mm square.

There are various non-impact printing methods used in a printers in general use. Each method has its advantage and disadvantage in terms of equipment cost price, quality, reliability, speed and equipment size, etc. We have investigated an imaging method by using Toner Jet in which a visi ble direct image is obtained using an electrostatic field to make the toner sticking to the paper. Images obtained from the Toner Jet Printer (TJP) are of equal quality to those obtained by electrophotographic method. In this paper, we confirmed that the Toner JET method will be an effective new electrical applied method.

The CHIMES (Computer-Human Interaction Models) tool was designed to help solve a simply-stated but important problem, i.e., the problem of generating a user interface to a system that complies with established human factors standards and guidelines. Though designed for use in a fairly restricted user domain, i.e., spacecraft mission operations, the CHIMES system is essentially domain independent and applicable wherever graphical user interfaces of displays are to be encountered. The CHIMES philosophy and operating strategy are quite simple. Instead of requiring a human designer to actively maintain in his or her head the now encyclopedic knowledge that human factors and user interface specialists have evolved, CHIMES incorporates this information in its knowledge bases. When directed to evaluated a design, CHIMES determines and accesses the appropriate knowledge, performs an evaluation of the design against that information, determines whether the design is compliant with the selected guidelines and suggests corrective actions if deviations from guidelines are discovered. This paper will provide an overview of the capabilities of the current CHIMES tool and discuss the potential integration of CHIMES-like technology in automated graphic arts systems.

Color Management Systems have been used for several years in Desktop Publishing (DTP) environments. While this development hasn't matured yet, we are already experiencing the next generation of the color imaging revolution-Device Independent Color for the small office/home office (SOHO) environment. Though there are still open technical issues with device independent color matching, they are not the focal point of this paper. This paper discusses two new and crucial aspects in using color management in color document processing: the management of color objects and their associated color rendering methods; a proposal for a precedence order and handshaking protocol among the various software components involved in color document processing. As color peripherals become affordable to the SOHO market, color management also becomes a prerequisite for common document authoring applications such as word processors. The first color management solutions were oriented towards DTP environments whose requirements were largely different. For example, DTP documents are image-centric, as opposed to SOHO documents that are text and charts centric. To achieve optimal reproduction on low-cost SOHO peripherals, it is critical that different color rendering methods are used for the different document object types. The first challenge in using color management of color document processing is the association of rendering methods with object types. As a result of an evolutionary process, color matching solutions are now available as application software, as driver embedded software and as operating system extensions. Consequently, document processing faces a new challenge, the correct selection of the color matching solution while avoiding duplicate color corrections.

Hard copy is still preeminent in the form of textbooks or lab manuals in most training environments despite inroads made by microcomputer delivery. Cost per copy is still a major factor but one that is offset by convenience and the capability of including a small number of crucial color illustrations for low run laboratory manuals. Overhead transparencies and color displays are other major educational applications in which electronically generated color hardcopy is just starting to make an impact. Color hardcopy has been perceived as out of reach to the average educator because of probatively high costs in the recent past. Another reason for the underutilization of color in instruction is research that suggests that color distracts instead of directing attention among learners. Much of this research compares visuals which are designed to convey simple visual information, and in this case complexity does often get in the way of comprehension. Color can also act as an advanced organizer that directs visual perception and comprehension to specific instructional objectives. Color can elicit emotional responses from viewers which will assist them in remembering visual detail. Not unlike any other instructional tool, color can add or distract from instructional objectives. Now that color is more accessible in the hard copy format, there are many new ways it can be utilized to benefit the public or corporate educator. In the sections that follow color hard copy is considered in its present areas of application, in context to the suitability of visuals for instruction, as a important component of visual literacy and lastly in the development of measures of picture readability.

The expression 'Plain' paper was coined in the early days of electrophotography to distinguish the capabilities of the new dry toner based photocopying process which did not require a sensitized or special coated paper to produce an image. Currently 'Plain' paper is considered in the electronic printing industry, to be any uncoated paper, usually of the type used in office photocopying applications. It is assumed that all 'Plain' papers are identical or at least equivalent in their properties such that all papers will give equivalent print quality performance. Due to the wide availability and low price of 'Plain' papers, it is also considered desirable by vendors of electronic marking processes, that their technology be capable of producing good image quality on 'Plain' paper. The chemical and physical differences which can occur among 'Plain' papers are discussed with respect to the specific image quality and engine reliability requirements of the major nonimpact electronic marking technologies, including electrophotography and laser printing, electrographic and ionographic processes, thermal transfer and ink jet. Paper properties of interest include, smoothness, surface energy, electrical resistivity, porosity and aqueous and nonaqueous liquid adsorption. Color printing has added additional requirements to paper quality, if good image quality is to be achieved and maintained. Given the apparently conflicting requirements for some of the electronic marking technologies, it will be a challenge to define a single grade of paper which will produce optimum print quality for all electronic printing processes.

Dry time, resolution and color density are the key design parameters for ink jet film design. These design parameters may be addressed through careful selection of coating formulation. In addition, as part of the total printing system, these parameters may be addressed through the inking system and printing algorithms. The influence of the coating design on dry time, resolution and color density will be fully explored here.

Thermal dye transfer (TDT) imaging has established itself as the state- of-the-art process for high quality, continuous tone, nonimpact printing. Imaging quality from this process rivals conventional silver halide photography and exceeds other nonimpact printing technologies. Because this output appears to be virtually indistinguishable from photographic prints, there has been an expectation that all the quality attributes of silver halide photography are embodied in a TDT print. However, there are many significant differences that affect output quality between these two technologies. These differences are primarily in color gamut, print artifacts, Dmin, grain/sharpness, and image stability. The range of colors reproducible by a color, hard copy device, known as its color gamut, is dictated primarily by the image- forming dyes used by the device. The size and shape of a device's gamut is controlled by the spectral density distributions of these image forming dyes, the Dmin of the receiver base, the Dmax of each dye, the amount of light scatter, and the spectral distribution of the viewing illuminant. The spectral density distributions of dyes also have an impact on illuminant sensitivity, which is a predictor of how much the color balance of a print will change with a change in illuminant. By determining and then using characteristic curves for various image- forming dyes, we have been able to calculate and compare the color gamuts and illuminant sensitivity of TDT imaging with other technologies (color monitor and silver halide photography, for example). The differences we have found can have a significant impact on output quality, depending upon the application. Compared to conventional photography, thermal dye transfer prints have traditionally had inferior light stability and resistance to damage from fingerprints. In addition, thermal dye transfer prints have been aggressively attacked by plasticized polyvinyl chloride sheets and folders commonly found in office and home environments. We will describe a major advance in thermal dye transfer imaging technology that greatly improves the image stability position of thermal dye transfer images. This advance is derived from the addition of a thin protective layer onto the final print. To add to customer convenience, the protective layer is integrated into the dye donor ribbon as a 4th patch. The protective layer is laminated to the final print using the thermal print head. TDT print artifacts may also influence the quality of TDT output. These defects can include print head streaks, dust and dirt spots, printer banding, and donor ribbon wrinkling. The origin of these defects will be described.

To continue the evolution of thermal inkjet printing, key technology developments are needed. These include the ability to print text output as fast as laser printers, determining and delivering realistic color print speeds for the consumer, lower cost of the printer and the output, and finally, realistic natural images on a wide selection of medias. In this paper, the resolution and quality needed for different types of printing are reviewed. The technical feasibility is assessed in terms of enabling subtechnologies that need to be developed to support the ultimate application goals for each type of printing. Key developments required are outlined and the underlying technical challenges that must be met in order to enable faster text, faster graphics, and high-quality image output are listed. Large arrays, higher resolution, and the need and methods for producing variable spot size from one nozzle are reviewed and assessed.

Although bubble-jet printers have gained a high market share there are still open questions left for fully understanding the various physical phenomena of the processes in ink jet firing chambers. Surface tension effects play a key role in this context. For example, these effects strongly influence the formation of the bubble at its growth and collapse and the refilling of the firing chamber. In this paper an improved model approach in combination with a new measurement technique to study surface tension effects for bubble-jet printheads is presented. Main attention is directed towards the simulation of the flow in the chamber and the droplet formation including surface tension effects. The model calculations have been carried out for a commercially available printhead. In order to support the simulation results a new class of measurements have been developed, namely, measurements under closed-pool conditions. This enables the examination of the growth of the vapor bubble under real conditions in side-view. The basic idea for preparation of the firing chamber is presented. It is shown that the new measurement technique does not affect the physical processes in the firing chamber and, consequently, the results can be compared with the simulations directly.

We have taken advantage of the improved time resolution (< 50 ns) of a newly developed laser stroboscopic system to study the early stages of vapor bubble nucleation in a thermal ink jet printhead. A transparent channel printhead provides optical access to vapor bubble formation and drop generation processes. Vapor bubble nucleation was found to proceed from the initial formation of localized microbubbles (< 50 ns) that spread with time until a uniform sheet of vapor covers the entire heater surface. The time duration for this process was 400 to 600 ns, depending on the heater voltage. The critical role of the heater surface is demonstrated clearly by the fact that preferential vapor microbubble nucleation sites are observed to persist over long time periods. The region of the heater surface subjected to vapor bubble collapse exhibits different microbubble properties than the rest of the heater surface.

The nucleation and growth of a vapor bubble from superheated water is the triggering event for the eventual ejection of an ink drop in the thermal ink jet (TIJ) printing process. A high speed stroboscopic system capable of time resolving the kinetics of the nucleation process has been developed. The core of the system is a semiconductor laser and a high speed electronic driver that is used to replace the more conventional flashlamp strobe. The time resolution of the new laser strobe is < 50 ns, which is 20-40 times higher resolution than the 1-2 microsecond(s) duration of the typical flashlamp strobe. We observe site specific formation of small vapor bubbles on the surface of a TIJ heater that are stable for up to 0.5 microsecond(s) . These site-specific bubbles also play a role in the growth of the continuous vapor bubble, the expansion of which imparts the force to eject an ink drop. A model is proposed that explains these observations.

This paper investigates the capabilities of a micro system design for a silicon-based thermal inkjet printhead. The presented design is based on the experiences with an earlier prototype of a bubble jet printhead containing 50 drop ejectors and a printing resolution of 300 dpi. In order to minimize the number of leads connecting the printhead with the printer, an electronic circuit has been integrated on chip. This provides also a lot of features for testing and monitoring the printhead. Due to the electronic circuit a detailed test procedure can be carried out. The test routine reveals data transmission errors, and short and open circuits of the MOSFET power switches. The presented smart printhead has an integrated sensor monitoring chip temperature and a timer supervising the heating pulses which prevents the heater elements from being damaged. Because of current limitations the heater elements have to be fired in groups. Depending on the number and position of spots that are printed at one time there are more or less visible artefacts. Computer simulations have been carried out to evaluate the effect of different timing sequences on print quality.

The status and potential of ink jet technology is discernible in its major technical literature forum: worldwide patents. Most ink jet technical activity is focused in commercial research and development laboratories where proprietary considerations make patents the norm for publication. Currently there are about 2,000 ink jet disclosures issued annually with over 200 enterprises represented. Ink jet patent activity is increasing about 25% per year driven by a rapidly expanding base of products, applications, and revenue. An analysis of the ink jet patent literature reveals a few major themes (i.e. continuous ink jet, piezoelectric drop-on-demand, and thermal ink jet) and numerous minor ones (i.e. electrohydro-dynamic extraction, magnetic drop-on-demand, Hertz continuous, acoustic ink printing). Patents bear witness to transformations in the industry as dominant players of the 1970's have given way to new leaders in the 1990's. They also foretell important commercial developments in ink jet's near term future. When studied in aggregate, the patent record reveals patterns for the industry in general as well as for individual companies. It becomes possible to use the patent data base not only to identify technical approaches and problems for specific firms, but also to track progress and monitor changing strategies. In addition, international filing patterns can provide insights into industry priorities. This paper presents an overview of ink jet technology as revealed by the patent literature. It will include a 25 year perspective, a review of trends over the past five years, and a survey of today's most active companies and their technical approaches. With this analysis, it will be shown that the information inherent in the patent record is more than the sum of its individual disclosures. Indeed, by using it, we can outlook whither goes ink jet.

This paper is a condensed version of an invited overview on the technology of film hard-copies used in radiology. Because the overview was given to an essentially nonmedical audience, the reliance on film hard-copies in radiology is outlined in greater detail. The overview is concerned with laser image recorders generating monochrome prints on silver-halide films. The basic components of laser image recorders are sketched. The paper concentrates on the physical parameters - characteristic function, dynamic range, digitization resolution, modulation transfer function, and noise power spectrum - which define image quality and information transfer capability of the printed image. A preliminary approach is presented to compare the printed image quality with noise in the acquired image as well as with the noise of state-of- the-art cathode-ray-tube display systems. High-performance laser-image- recorder/silver-halide-film/light-box systems are well capable of reproducing acquired radiologic information. Most recently development was begun toward a display function standard for soft-copy display systems to facilitate similarity of image presentation between different soft-copy displays as well as between soft- and hard-copy displays. The standard display function is based on perceptional linearization. The standard is briefly reviewed to encourage the printer industry to adopt it, too.

Traditionally, color mapping has not been utilized for diagnostic medical imaging. Color mapping was not possible prior to the emergence of electronic imaging modalities. Diagnostic imaging is considered in view of its purpose and goals as distinguished from photographic and scientific imaging. The applications for color in digital imaging modalities are discussed, as well as research directions for color utilized as a means of increasing the information density available to an observer. Requirements for color hardcopy are discussed.

With the proliferation of various new modalities, in Medical Imaging, there has been a need for compatible hardcopy. In order to render color or colorized images, for diagnostic imaging, it is necessary to have high quality hardcopy. Thermal media has the necessary characteristics to display images emanating from most of the new medical imaging modalities. Furthermore, new image presentation techniques are enabling the display of some medical images, which could only be displayed using silver halide media.

Ink jet printing provides the medical imaging field with a unique combination of properties. The combination of high quality grayscale, color capabilities, and inexpensive paper copy is new to this industry. One ink jet technology is reviewed, and applications where the technology is being used are described.

The success of digital printing in the office and the home is a matter of historical fact. Facsimile machines, personal printers, office and networked printers are the mainstay in the hard copy output of document . Newmultifunction digital output devices which combine the functions of copying, printing, faxing and collation will soon become prevalent. At the high end, electrophotography, now a sixty-year old technology, still reigns supreme. Now that cartridges allow the replacement of the major components of the process, the word "reliable" is finally being associated with electrophotography! Cartridges also facilitate a captive, ongoing, consumable business, vital to the profitability of manufacturers of hardware.

The paper describes the advantages of Lithography for quality reproduction at high production speeds by comparison with other digital printing systems. The claim is made that silver halide offers the best and most flexible technology for CTP and that the use of the single sheet diffusion transfer method offers the most elegant, simple and therefore the most practical of solutions to the problem of providing Silver halide photographic properties on a litho printing plate. The changes in litho plate technology are briefly reviewed, the specific requirements of computer to plate are outlined and then the application of single sheet silver halide diffusion transfer technology to computer to plate (CTP) are described in more detail. A representative sample of output recorders (platesetters) are described and some possible technology routes for higher speed and lower cost are reported.

Minor defects in line spacing and/or density variations can cause visual artifacts in images generated by output scanners. This paper presents a method to quantify such errors using a measurement station that characterizes both the line spacing and the relative density of lines printed at 1200 to 2400 lines/inch. While other measurement methods exist (e.g., grabbing single frames of data from a micro-densitometer), possibly most restricting is the limited number of lines that can be measured due to the trade-off between field of view and resolution. Moire effects may also be utilized for spacing checks, but the results are not sufficiently quantized. The method being presented does not limit the number of lines that can be measured at one time, therefore large regions can be used to perform spatial frequency analysis. In 1- on/1-off line patterns, variations of only 2-3% in line spacing (approximately equals 40 microinches in 1200 LPI) are perceptible. Very minor variations in density can also cause visual artifacts. Distinguishing between a spacing error and a density error is critical to the troubleshooting process. This measurement system was designed to have a theoretical positional resolution of 0.417 microinches. Repeatability of line space measurements for this type of pattern is typically better than 10 microinches.

Thermal recording with a laser beam is a promising process. More thermal recording applications in the graphic arts market and also in the medical and PCB imaging markets are surfacing in recent years. Thermal recording has advantages over traditional photographic recording in that it is dry and environmentally benign. Also thermal recording is a threshold process and therefore yields sharper images. Thermal recording media, however, require much higher powered lasers to record than conventional photographic media. We must therefore carefully determine the optimal parameters for recording thermally most efficiently. In this paper, we determine the minimum beam power requirements, in terms of recording media format, throughput and media sensitivity. We also analyze in this paper the spot profile required to achieve the optimal recording efficiency, assuming it is a controllable design parameter. Since the efficiency is not the only performance requirement from a recording system we discuss other important parameters of image quality which affect the spot profile and beam power choice for a thermal recording system.

This model simulates a laser imaging system that uses thermal energy as the exposure mechanism. The recording media is a metal film, typically bismuth, laminated between two transparent polymer sheets. It uses an input stream of binary pixel information to modulate a simulated array of lasers. Absorbed laser energy is converted into heat in the metal film of the recording media. The metal film is disrupted by the heat, allowing light to pass through in the exposed regions. The energy source, generally a laser diode or laser and AOM combination, exposes a recording media in response to the input binary data. The energy source is directed at successive positions in a line across the recording media by a scanning mechanism such that each such position reflects the position of each binary bit in the input stream. Successive lines of input data are positioned adjacent to each other to build an image on the output media that is representative of the input data. The purpose of developing this model was to provide an easily accessible and usable software package for quickly modeling different imaging systems based on thermal recording media. Toward this end the model was developed for the Windows 3. 1 operating environment with all parameters of the model available to the user. This includes the defining parameters for the laser beams, the modulation and switching systems, the thermal characteristics of the recording film, the recording data pattern and the pixel sample size. The simulation can be paused at any time to review the results as they are computed and these results can then be printed while the simulation is paused. The results, both of energy and temperature, can be measured on screen through user positioned guide lines overlaying the graphic display. The performance is such that less than one second is required for each pass through the model, making the system fast enough to use in exploring a wide range of system parameters when creating a new recording machine. Some systems will have multiple laser beams exposing multiple lines in parallel. This is a particularly important case to model due to the potential for thermal cross talk between the beams, particularly at low recording speeds where there is more time for heat to flow out from the exposed pixels. The model can support as many as four beams arranged in a single line. The line can be oriented at an angle relative to the direction of travel and each beam may be individually placed on the line. The model is composed of six discreet elements that reflect the primary components of a laser imaging system. These elements are the input binary data stream, laser driver circuit, laser modulator, laser spot at the recording media, the laser scanner mechanism and the recording media itself. The user interface of the model is designed to allow independent control of each element in the model. In addition there are provisions for examining the results of the model at various times during the simulation as well as the final output of the model. The software provides a means to store and retrieve a models parameters as well as to print the results of the model. A 50 MHz 486 based PC compatible system running DOS 5.X and Windows 3.1 was used to develop and run the model. The system contained 16 mBytes of RAM, though systems with 8 mBytes have successfully run the software. A color VGA display was used to display the model results.

Methods of hard copies recording based on thermal interaction of the beam from CO₂ or YAG lasers with various kinds of films on any substrates have been developed. The recording processes are single-step and require no additional development. Among them are: (1) Laser thermodestruction of thin mask layers or of a material surface on any kinds of substrates. (2) Laser thermochemical reactions of thermal decomposition of metal salts in solid state phase on a surface of various hygroscopic substrates. The laser recording devices using the methods, described above have been developed and are manufactured now; they allow one to record hard copies with a size of up to 27 X 31 inches, a resolution of 4000 dpi.

Many of the papers and inks used to produce color hard copy products contain fluorescent materials. Most density and/or color instruments use the ratio of value of the light returned by the sample at each wavelength relative to that returned by a white calibration standard to derive the measurement value. Generally, no effort is made to differentiate between light reflected by the sample and light emitted by the sample due to fluorescence. The blue emitted light resulting from the inclusion of fluorescent whitening agents (FWA) in graphic arts materials is excited by violet and ultraviolet (UV) light in the instrument illumination source. Differences in instrument source UV intensity can cause significant differences in the blue reflectance values of FWA containing samples reported by the instrument measurement system. Standard reference materials (SRM) which contain known amounts of FWA are commercially available. These SRMs allow a semiquantitative assessment of the UV content of an instrument's illuminating source. A further refinement, using thin UV cutoff filters, allows the qualitative determination of the presence or absence of FWA in paper samples. We anticipate that with the use of other thin filters, measurement errors caused by visible light excited fluorescence of inks, particular yellows, will be possible.

Color continues to be an important issue in both the US and international graphic arts standards activity. Standards have been published defining color measurement and computation requirements, scanner input characterization targets, four color output characterization and reflection densitometric data. Work continues on standards relating to ink testing, reference ink color specifications, and printing characterization. Work has been completed, and is being published in an ANSI Technical Report, that relates the measured colorimetric data for printed color to the CMYK input for press proofing meeting SWOP specifications. Implementation of the color standards developed by IT8. CGATS, and ISO/TC130 is being promoted by the Open Systems Color Association (OSCA). Key among the OSCA activities is the development of measurement protocols and a registry of color output characterization data. These color standards are also finding applicability in the work of the International Color Consortium which is developing the interfaces to allow color profile data to be exchanged between color management systems. This presentation will summarize the published graphic arts color-related standards and review the current status of the work in progress.

Most spectrometers illuminate a dispersing grating with collimated light. This form of the instrument is optimum when high spectral resolution is required. There are many applications such as color matching and desktop publishing that require only 10 nm resolution over the limited spectral region of 390 nm to 700 nm. In addition, the design must lead to a configuration that is affordable. This paper describes a spectrometer design that uses divergent light incident on a grating. The grating is followed by a glass lens used to focus the light on the exit slit. This design uses a simple scanning mechanism that combines the motion of the grating with the chromatic aberrations of the lens to produce a linear-dispersion constant-bandwidth spectrometer. In this configuration the spectrometer is compact a light.

The properties of the total printing transfer function are studied using halftone test prints and automatic analysis of the acquired data. a method for determining the dot gain, both physical and optical, based on the colorimetric properties of the halftone dots is presented. To estimate the physical dot gain the method identifies the ink and discriminates between the different colors and the paper using normalized color distributions for each printing ink. The color distribution idea is based on the fact that between the colorimetric centers of gravity (in CIELAB color coordinates), the possible colors of the print are almost one dimensionally distributed. This has been established through three dimensional visualizations of the color gamut for different printers and also for news print. In this approach a simulation how light is scattered in the paper is used to complement the measurement of optical dot gain. Using digital image processing and data modeling through Singular Value Decomposition, properties of the color distributions for halftone prints are identified. The properties are identified by examining the basis functions corresponding to the largest singular values. Links to the physical properties of the ink and the paper are discussed.

A printer model is described for dot-on-dot halftone screens. For a given input CMYK signal, the model predicts the resulting spectral reflectance of the printed patch. The model is derived in two steps. First, the C, M, Y, K dot growth functions are determined which relate the input digital value to the actual dot area coverages of the colorants. Next, the reflectance of a patch is predicted as a weighted combination of the reflectances of the four solid C, M, Y, K patches and their various overlays. This approach is analogous to the Neugebauer model, with the random mixing equations being replaced by dot-on-dot mixing equations. A Yule-Neilsen correction factor is incorporated to account for light scattering within the paper. The dot area functions and Yule-Neilsen parameter are chosen to optimize the fit to a set of training data. The model is also extended to a cellular framework, requiring additional measurements. The model is tested with a four color xerographic printer employing a line-on-line halftone screen. CIE L^*a^*b^* errors are obtained between measurements and model predictions. The Yule-Neilsen factor significantly decreases the model error. Accuracy is also increased with the use of a cellular framework.

Color transformation from RGB to CMYK is a significant problem in color reproduction. Since black ink is a redundant component, it is impossible to find a unique set of CMYK ink quantity suitable for an input RGB color. This paper proposes an algorithm for UAR, using the direct color mapping method from RGB to CMYK. It directly searches a measured gamut space for a printer for more than one set of CMYK ink quantities suitable for an input color with out using a reproduction model or a nonlinear equation. A set of CMYK ink quantity, suitable for an input color, is flexibly calculated from several sets of CMYK ink quantity by using interpolation controlled by an adjusting coefficient of black ink quantity. The flexible computation of black ink quantity makes it possible to adjust a delicate image appearance. This algorithm can be applied to various kinds of printers, because it does not require a model of the printer's color reproduction mechanism.

This paper describes an extension of bilevel error diffusion technique from one component per pixel (originally gray image), to an arbitrary set of colors, with an arbitrary number of color components per pixel. The binary and multilevel variants of the algorithm are derived as particular cases of the general algorithm. The color set used in error diffusion procedure is selected according to the image that must be reproduced. The error diffusion procedure is investigated with respect to three parameters: size and shape of the local array around the current pixel where the error of color rendition is evaluated, weight mask of errors in local array and the color space where the error distance is computed. The error diffusion procedure is applied and adapted for the designing of the textile sewing process. The original image is resampled corresponding to the resolution determined by sewing process parameters, and the influence of the texture of sewed material is taken into consideration for the simulation process that enables the preview of the final result.

This paper introduces an alternate standard for film archiving based on digitizing the dye densities of the film rather than the color (XYZ or RGB). The color of the film is encoded by the storage of two types of information: (1) the analytical densities of the dyes, which must only be stored once for each film; and (2) the dye concentrations for each pixel of each frame. If the analytical densities of the dyes are known, then the concentration of each dye can be estimated by measuring the logarithm of the transmission of the film in as few as three frequency bands. A formalism for accomplishing this estimation, as well as the estimation of the dye density curves, will be presented. The error of this digitization technique as a function of filter bandwidth and a function of the number of spectra transmission measurements used for the dye concentration estimation will be quantified. In addition, the impact of this technique for film restoration will be discussed.

In this paper, a new edge enhanced error diffusion algorithm which is based on the Eschbach's algorithm is proposed. Thick edge artifacts with large edge enhancing factor as well as less edge enhancement effects for the bright or dark pixel values are observed in the previous algorithm. By analyzing the phenomena, a new improved algorithm is proposed by using the diffused error sum and input pixel value. An input pixel is classified into a normal- or edge-region pixel based on the error sum criteria. Then, a new error calculation is employed for the edge-region pixel, while conventional error calculation is used for the normal- region pixel. The proposed method requires only a few additional calculations, and provides edge enhanced binary output images. The edge is less influenced by the brightness offset and thick edge artifacts are reduces.

This paper reviews the color image processing techniques used in the printing industry for the color space transformation. Generally, the techniques can be classified as the color mixing models, multiple regression, 3D lookup table (LUT) with interpolation, neural network, and fuzzy logic. The following techniques are briefly discussed. (1) Color mixing models such as the Neugebauer equations, Yule-Nielsen model, Clapper-Yule model, Beer-Bouguer law, and Kubelka-Munk theory. (2) Multiple regression. (3) 3D LUT with four geometric interpolations - trilinear, prism, pyramid, and tetrahedral. (4) Artificial neural networks of the multilayer feed-forward and cascade correlation nets. (5) Fuzzy logic. These techniques are compared, whenever possible, with respect to the accuracy, memory requirement, speed, and computational cost.