An Analysis of how altering exposure effects color differences in critical color areas on electrophotographic off-press proofs

The purpose of this paper was to quantitatively analyze off-press color proofing methods for advertising material appearing in halftone publication gravure printing. This type of proofing has been an area of debate for the publications industry, especially in reference to the print quality of advertising material. The correlation between dot gain characteristics and the resulting color differences of off-press color proofing methods has been the center of greatest controversy. This paper has tested to determine if a correlation exists between dot gain characteristics and the resulting colorimetric-matching ability for color proofing methods used in halftone publication gravure. The variable dot-gain feature of an electrophotographic proofing system was tested to determine if this feature improved the color matching ability of the off-press proof to the SWOP offset press proof. This system was analyzed by its\u27 ability to objectively match the SWOP offset press proof for dot gain aimpoints. These aimpoints are used as the quality control tool for advertising material appearing in both halftone gravure and web offset publications printing. The experiment concluded that the dot gain characteristic curve of the electrophotographic off-press proof could be altered to quantitatively match closer to the dot gain of an offset press proof printed to SWOP/GAA Specifications. However, the data did not completely support the authors\u27 hypothesis. A direct correlation between dot gain and the resulting delta E values could not be established. None of the data collected from the electrophotographic test sets completely proved that a change in dot gain produced a closer colorimetric match to the SWOP/GAA Offset Press Proof

A Study utilizing halftone based digital proofing systems in the flexographic printing process

Contract proofing for printing has been traditionally done by press proofing. This is costly and wasteful, not just in terms of equipment and labor but also in terms of expendables. The advent of off-press proofing was greeted with some degree of uncertainty by the printing industry. With press proofing, the proof was literally a preview of what would happen on a press. The press proof, although often printed on a different press, generally used the same type of inks, plates and substrate that would characterize the final print. With offpress proofing, printers were comparing apples to oranges; instead of comparing a press sheet to a press sheet they were comparing a press sheet to an approximation of a press sheet. However, over time as printers learned to read off-press proofs, they became accepted as contract proofs. The same situation has now befallen digital proofs. In the particular case of flexography, the proofing problem is a bit different. Off-press analog proofs were designed with lithography in mind, they were characterized to simulate lithographic dot gain. In order to make a proof that looks like a flexographic press sheet, two sets of films are required; one which compensates for flexographic dot gain (this is the set from which the job would be printed) and one which has extra dot gain built into the highlight and quarter- tones (this is the set that the proof would be made from). This extra set of films is wasteful and time consuming to generate. Digital proofing seems to be well suited for flexography, because the dot gain can be built into the proofing system and no extra film is required to create the proof. At the most basic level there are two types of digital proofers available; those which simulate halftone dots and those that do not. Whether or not the dots are necessary is open to discussion, however, in the case of flexography the dots appear to be crucial. For this research document it was decided that the halftone dots were preferred. The reason for this is that at about 133 lpi the rosette patterns formed by halftone dots are at the threshold of resolution by the human eye. For more course screen rulings this is even more critical. Much of flexography is printed at screen rulings of 133 lpi or lower, so very often the dots can be resolved by the eye. Therefore, the mindset at the beginning of the research was that if the dots can be resolved on the press sheet then the dots should be resolved on the proof. The major thrust of this research was to observe whether or not a halftone-based digital proofer can simulate the appearance of a flexographic press sheet. A flexographic test form was created and printed on a film based substrate. A press sheet was sent to two vendors who manufacture halftone proofers. The proofing systems are not mentioned by name; they are instead referred to as Digital Proof A and B. They then attempted to match the press sheet as closely as possible. Thus, through reverse engineering, the vendors created a device profile for this set of printing conditions. Upon receipt of the proofs, they were compared to the press sheet in terms of optical density, hue (AE) and halftone dot size. Later, a visual assessment was executed to observe how closely the digital proofs matched the press sheet using a 3M Matchprint, that had been altered to approximate flexography, as the reference or control proof. The results showed that there were significant differences between proof and press sheet in some instances and insignificant differences in others. In terms of the physical structure of the halftone dots, the 3M Matchprint had the closest match to the press sheet dot structure. In terms of physical dot size; digital proof A best matched the 50 and 75% dots and the Matchprint matched the 5% dots the best. In terms of optical density; digital proof A best matched the density of the 25% dots, digital proof B best matched the density of the 5% dots and the Matchprint best matched the 50 and 75% dot patches. In terms of AE values (color or hue difference); the Matchprint most closely matched the press sheet, digital proof B was next, and digital proof A was last. In terms of a visual match, the three proofs were found to be statistically equal in their ability to visually match the press sheet. The visual match being the most powerful of the criteria; shows that the measurable differences in the proofs did not directly affect their ability to match the press sheet. The results show that either of the two halftone digital proofs could have been used in place of the 3M Matchprint. The results also question the need for halftone dots in a proof. This is primarily because the two halftone digital proofs utilized a different RIP than the Agfa generated films for the 3M Matchprint and flexographic press sheet. Yet the visual observations made by the judges could not, at a normal viewing distance, discern this difference. The conclusion is that there is no visual difference between the halftone digital proofs and the 3M Matchprint proof in terms of visually matching the press sheet

A Study using a high-addressability Inkjet Proofer to produce amhalftone p roofs matching Kodak approval in color, screening, and subject moiré

An investigation of the feasibility of using a high-addressability inkjet printer as an alternative to the traditional proofing systems, such as Kodak Approval, was completed. The inkjet proofs must match the press sheet in terms of color, screening, screen angle, screen ruling, and screen dot size. The relatively low cost per print and the ability to incorporate color management makes inkjet technology a potential candidate also for use as a proofer for these requirements. Existing software and patents on halftone inkjet proofing were analyzed. A test form was designed to test the proofing models for screening, screen angle, and screen ruling observed in the proofs. Several workflow models were developed to generate proofs that matched the press sheet in color and moiré. Solutions for the encountered problems were tested until, finally, an optimized model was obtained that was capable of generating halftone inkjet proofs matching the press sheet visually in terms of color and moiré. This model is simple, cost effective and does not require any special software. However it is limited by the constraints of file size of Photoshop

The development of a Java based GIS viewing tool : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Technology in Information Engineering at Massey University

Geographic Information Systems (GIS) industry sources quote the ratio of power users to casual users at 1000:1, within New Zealand this figure has been found to be 30:1. The casual user is often under-supported, with slow and cumbersome viewing tools. This project implements a full data download system in Java for use with Genasys (New Zealand) GIS software. Three components were developed; a vector data handler, an image download system, and a database client. These components were integrated to form a powerful client that offered a significant performance increase over the "server based" client. The image download system outperformed the "server based" client by over 400%. The vector data handler outperformed the "server based" client by over 50%, while the database client was over 250% quicker. GIS users rated all components to be of significant benefit, offering improved performance over their current GIS viewing tools. The work completed in this thesis provides Genasys (New Zealand) a useful tool to enable powerful, fast and stable Java based GIS viewing clients. Keywords: GIS, Java, computer graphics, image pyramid

A Designer\u27s guide to the evaluation of digital proofs

Digital color proofs and pre-proofs are used by graphic artists and commercial printers throughout the prepress process. However the prepress process has undergone radical changes over the past decade due to the introduction of desk top publishing and desktop prepress. Alongside of the desktop publishing revo lution has come a multitude of new digital proofing technologies for use in this ever changing environment. Technologies including, but not limited to, liquid inkjet, dye sublimation, continuous inkjet, color laser, and thermal wax transfer printers have provided an entire range of color accuracy and price suitability to many of their users. However one needs to be able to understand the practical applications and limitations of these technologies to make a suitable choice for a specific prepress operation or design process. Therefore a handbook for the users of digital proofs has been created for their benefit. The underlying structure of this handbook is based on the following six chap ters. The first chapter, entitled Communicating with Prepress and the Attributes of Digital Proofing, contains multiple parts. Firstly, it contains information for the designer in regards to the advantages and disadvantages of all types of digital output devices. It discusses the advantages which digital output devices may or may not have over conventional proofing systems. Additionally, ideas such as the vantages and drawbacks of preproofers and proofers is elaborated upon. Information for this part of the chapter was obtained through questionnaires completed by, and interviews with print buyers, art directors, and production managers from advertising agencies and prepress providers in the Rochester area. More information for this section of the first chapter was obtained through various manufacturer\u27s literature, printing industry reports and various periodi cals. Chapter One also discusses ideas behind the application of color printers (preproofers) and digital proofers. These ideas address issues which pertain to the application of specific printing and proofing processes to specific phases of the creative and production processes. Additionally, discussions regarding proof ing costs, qualities, and production turnaround time may be found in this part of the first chapter. Information for this section of Chapter One was obtained through information found in printing and publishing related periodicals, as well as in manufacturers\u27 literature. Finally, the first chapter develops a system for the correction of digital preproofs and proofs. Multiple groups of ideas pertaining to the correction of digital output are discussed. Some of these include sections entitled Digital File Tracking and Identification, Evaluation of Design Elements, Evaluating Colors, Element Positioning, and Element Dimension Adjustments. Information for this part of the chapter was obtained through the evaluation of previously corrected digital con tract proofs and preproofs, as well as the interviews and questionnaires men tioned above. The second chapter, entitled Proofing Typography, displays the many different ways that printing and proofing technologies affect text type and display typog raphy. Using the CD-Rom included in the back of the book, one may view on screen how the following technologies affect type ranging from 3 points to 72 points in size: liquid inkjet, large format liquid inkjet, phase-change inkjet, ther mal wax transfer, dye sublimation, continuous inkjet, and dye ablation. Information and samples for this chapter were obtained through printing and proofing system manufacturers and advertising agencies in the Rochester area. The Color Primer and Chapter Three: Proofing for Imagery and Color, contain information for the designer which may be applied to proper evaluation of color on color prints and digital proofs. The Color Primer discusses subjects such as color space, the additive and subtractive color theories, and common color mea surement tools. Chapter Three then applies some of this knowledge in its discus sions of proper lighting conditions for viewing prints and proofs, and different human factors which influence the highly subjective evaluation of all digital color output. Information for this chapter was gathered using graphic arts and printing industry related periodicals and industry-wide books related to color and its reproduction. The fourth chapter, entitled Substrates and Digital Output, educates the design er about the effects on text, imagery, and graphics which occur when creating digital prints and proofs on a variety of papers. Various paper surfaces such as gloss, semi-gloss and matte surfaces are addressed. The affects of colored paper on imagery and graphics are also elaborated upon. Additionally, printing and proofing processes are discussed in regards to the substrates that they accept for output. Information for this chapter was gathered through manufacturers\u27 litera ture and various industry related books and periodical articles. The Proofing Process Supplement was created to familiarize the designer with all currently popular forms of digital output technology. The process supplement discusses the imaging processes used by the following digital output technolo gies: liquid inkjet, phase-change inkjet, thermal wax transfer, dye sublimation, continuous inkjet, and dye ablation. Additionally, the supplement contains brief explanations regarding screening technologies. Information for the process sup plement was gathered through manufacturers\u27 literature, interviews with pre press providers in the Rochester area, and interviews with technical representa tives from the manufacturers of devices which use the above digital, color out put technologies. Chapter Five, entitled Image Fidelity, simply illustrates how all of the current ly popular printing and proofing technologies affect graphics and imagery. Using the CD-Rom included with the guidebook, the reader may view magni fied and normal views of printing and proof sample imagery. Information noted by the reader in the proofing process supplement may then be actively applied when viewing these samples. Information and sample prints for the fifth chapter were gathered from several manufacturers and advertising agencies in the Rochester area. The sixth chapter, entitled The Acceptance of Digital Contract Proofing, discusses a new definition of the contract proof in regards to the evolution of digital proof ing. This chapter provides ideas for the designer, art director, and print buyer to realize when considering the use of digital contract proofing. Several questions are raised concerning what requirements a digital contract proof must fulfill depending upon the areas of its application and any agreements between the designer and prepress provider regarding their specific definition of a digital contract proof. Additionally, specific advantages of digital contract proofs, such as their ability to fingerprint a press and/or press run, are discussed. Finally, a discussion pertaining to the education of all users of digital proofing technolo gies is presented to aid the overall acceptance of digital contract proofing. Information for this chapter was obtained through the extensive interviews of leading technical and product oriented representatives from the manufacturers of currently used digital contract proofing systems. Many conclusions have been reached with the completion of this guidebook. In brief, the first and most prominent conclusion which may be reached states that the acceptance of digital contract proofing lies within the education of all designers, art directors and print buyers about digital printing and proofing technologies. As the use of digital contract proofing grows, education and inter est by all creative professionals will orient them towards their use of digital proofing systems. The next conclusion which has been reached is that the proper application of color printers and digital proofers is of major importance for the designer due to the added flexibility and rewards which result from the use of digital color out put devices throughout the creative and production processes. Another conclu sion which may be reached is that the display of proofing and printing process effects on text, graphics, and imagery serves to directly inform the creative pro fessional how these elements may be distorted by the utilized output device. Knowledge gained by the creative professional in regards to these effects helps to answer many questions regarding print or proof quality and proper output device application. Finally, additional knowledge gained by designers which pertains to proper viewing of all color output, color theories, color measurement, and proofing sub strates helps them to better communicate with those prepress and print professionals involved in the production process

A research to reduce interior noise in general aviation airplanes. General aviation interior noise study

The construction, calibration, and properties of a facility for measuring sound transmission through aircraft type panels are described along with the theoretical and empirical methods used. Topics discussed include typical noise source, sound transmission path, and acoustic cabin properties and their effect on interior noise. Experimental results show an average sound transmission loss in the mass controlled frequency region comparable to theoretical predictions. The results also verify that transmission losses in the stiffness controlled region directly depend on the fundamental frequency of the panel. Experimental and theoretical results indicate that increases in this frequency, and consequently in transmission loss, can be achieved by applying pressure differentials across the specimen

A tutorial in frequency modulation screening technology for lithography

An impressive diversity of opinions concerning many important aspects of the Frequency Modulation process are heard from users and vendors. It has not been difficult to catch a single vendor contradicting themselves within their own publications. Many of the claims vendors make are not supported by users\u27 experiences. Other users, on the other hand, have found many of the vendors\u27 brightest claims to be realistic. The information sought for this project was aimed to answer the question What can I expect if I implement Frequency Modulation screening technology in my shop today? In order to answer that question effectively, a clear and comprehensive understanding of the fundamentals of the FM process is required. The results and experiences of those that have had the opportunity to test the process are integral to a complete survey of the technology as it exists today. These requirements became the focus of this research effort. With limited access to any of the hardware and software necessary to implement an FM screen, research must necessarily be conducted by means of interviews, seminar attendance and surveys of recent publications. A list of questions was developed primarily out of the discussions at the GATF Technology Alert in Pittsburgh this past January and the Seybold Conference in Boston this spring. Both covered Frequency Modulated VI screening extensively. The GATF seminar was particularly helpful in developing a set of relevant questions that were shared by many of the users later contacted. Even among knowledgeable users and lithographic crafts people, the range of opinions on nearly every relevant topic covers the gamut of possibilities. A consensus among all of the sources included within this project on any major topic relevant to FM screening has proved difficult. The framework used here must therefore be flexible enough to accommodate contradictory opinions within its findings. Interviews were only conducted with experts recognized in the field and with users having first-hand experience in their own FM experiments. Testing and validation of the opinions and experiences reported here has not been part of this project, rather, the anecdotal experiences of many qualified users together are presented as a valid indication of what new users may expect when implementing the FM process. As it appeared that the range of possible answers to each question had been uncovered, the answers were formatted into short, self-contained bits of information. It is intended that a curious user be able to access complete chunks of knowledge contained within the document quickly without need for any supporting information (besides the requirement of familiarity with basic lithographic principles.) Most topics are less than a page. Some are more and a few are only short paragraphs. No first-hand verification of the information presented here has been attempted. By collecting the opinions and experiences of qualified users and researchers in the field familiar with the process, a body of knowledge is created which accurately reflects the state of the FM process as it currently exists and provides an answer to the question What can I expect if I implement Frequency Modulation screening technology in my shop today? Many early reports of FM screening implied that FM screening would soon sweep all of lithographic printing. As the realities and the difficulties involved in the process have become known and reported, it becomes apparent that a less enthusiastic and better balanced opinion indicates that FM screening can create a much improved print product though production difficulties make FM screening unlikely to gain wide use before dramatic improvements in the tools used to maintain process controls

A Comparison between the GCA/GATF off-press proof comparator and the GATF standard offset color control bar for identifying when a cromalin off-press proof is prepared to specification for web offset publication

Off-press proofing is a method of simulating the way a set of separation negatives or positives will look when printed without having to go to the printing press. In 1965, The Graphic Arts Technical Foundation (GATF) developed a proofing control device for production Lithography. The Standard Offset Color Control Bar was also utilized for off-press proofing. In 1983, The Graphic Communications Association, in cooperation with GATF, introduced The Off-Press Proof Comparator. This control device was designed specifically for this technology and intended to be used by both technical and non-technical personnel with equal and successful results. This thesis is concerned with the accuracy of both proofing bars using the Du Pont Cromalin system of off -press proofing to determine whether one control bar is better for judging whether a proof is made correctly to SWOP standards. It is also concerned with whether one control bar is more versatile than the other for both technical or non-technical personnel to use. The experiment consisted of a total sample population of forty experts from four different fields of the graphic arts industry. These four groups represent technical and non-technical users. Each participant was asked to look at samples of each color bar and choose which sample was made to SWOP standards. The results were applied to statistical methods of evaluation to give a final result. The final results of this thesis support The Graphic Communications Association\u27s claim that the Off-Press Proof Comparator in not only more accurate, but also more versatile for all members of the graphic arts community. The implications of this thesis are that a master comparative device can aid in evaluating if proofs are made correctly- A pictorial element is a helpful reference tool when used in conjunction with the master comparative device. A greater emphasis needs to be placed on viewing off-press proofs under corrected viewing conditions

Trends in soft proofing utilized as contract proofs in commercial lithographic printing

The proofing market has changed dramatically in recent decades. The introduction of Soft Proofing Systems--with the ability to quickly produce proofs at each step in the color reproduction process for a lower cost than conventional proofs--has been cited as a factor in changing the economies of this market. According to a research project conducted by Print Industries Market Information and Research Organization (PRIMIR, 2005) titled Dynamics and Trends in Color Proofing 2005-2010, only 1% of the final contract proofs made by respondents were color-managed monitor proofs. This percentage was expected to increase 8% by 2010. A pertinent question as to the future of proofing is the extent to which soft proofs have replaced other proofing technologies. The purpose of this quantitative research project is to determine the current adoption level of soft proofing systems for producing final contract proofs in general commercial color lithographic printing organizations, as well as the perception of both technical and job- related factors that influence judgments and decision of soft proofs as compare to hard proofs among printing companies in the US

Design characteristics unique to the flexographic printing process

The flexographic printing process has been used for package printing applications since the late 1800\u27s. Recent improvements in the flexographic technology have enabled flexographic printers to compete in new market areas that have historically been served by roto-gravure or offset lithographic printing. Occurring simultaneously with the flexographic printing improvements has been the infusion of personal computer-based graphic design capabilities. Designers can optimize quality only when they understand the strengths and weaknesses of the printing process that will be used to mass produce their design. Desktop design capabilities and the need for flexographic print quality to match or exceed lithographic and roto-gravure print quality are both factors that accentuate the need to understand the process in an effort to create a design that will be of high quality when printed flexographically. Designing package graphics for the flexographic process is unique for a number of reasons, ( the master image carrier (printing plate) is significantly different from roto-gravure and offset lithography, the inks used in flexography are significantly different form those used in gravure) and a wider assortment of substrates may be printed by the flexographic process than by the offset lithographic process. Each substrate has its own printing characteristics. This thesis will inform those who may be interested in designing for flexographic printing of the unique considerations that should be addressed when designing a package graphic for flexographic printing. Considerations specifically addressed are; variable repeat length capabilities, reverse-side printing, trapping, typography halftones and dot-gain screen ruling and substrate, step-and-repeat and flexographic plate elongation