Full reference image quality algorithms are standard tools in digital image processing but have not been utilized for printed images due to a "correspondence gap" between the digital domain (a reference) and physical domain (printed sample). In this work, the authors propose a framework for applying full reference image quality algorithms to printed images. The framework consists of accurate scanning of printed samples and automatic registration and descreening procedures which bring the scans in correspondence with their digital originals. The authors complete the framework by incorporating state-of-the-art full reference algorithms to it. Using data from comprehensive psychometrical experiments of subjective quality experience, the authors benchmark the state-of-the-art methods and point out similar results in the digital domain: the best digital full reference measures, such as the recently introduced visual information fidelity algorithm, perform best also for printed media.

The present article investigates a particular problem: how vividness can be calculated and used to evaluate printer quality. Vividness is a term representing chromaticness of colors (conceptually similar to chroma) and has also been adopted as one of the color adjectives in Inter Society Color Council-National Bureau of Standards (ISCC-NBS) color naming and practical color coordinate (PCCS) systems. According to ISO 20462-2, a new psychophysical method (triplet comparison method) was performed. As a result, an interval scale for vividness was established, and it was modeled as a function of mean chroma, C^*_ab, and lightness, L^*, of printer primary and secondary colors. Pearson correlation between the metric prediction and corresponding subjective data was about 0.96. The methodology was further extended to measure observer preference (preferred-vividness). Both preferred-vividness and vividness metrics were based upon chroma and lightness, but the contribution of lightness is much higher in the former (∼40%) case than in the latter (∼10%).

This article presents results of a study of color separation for the near infrared wavelength area in case of a double image reproduction. One image is observed in the visible spectrum and another one is detected under near infrared (NIR) light. For the purpose of NIR separation (CMYKIR), discussion is extended to CMYK working space as a device dependent on comparing several printing technologies. CMYK process inks characteristics enable visualization of the same color tone in default color settings with the goal to create two independent images in the same print; two independent pieces of information recognizable under two different types of lighting. The new approach to image reproduction is based on the idea of controlling and processing several images incorporated into one reproduction. This article unites five principles which are set for processing near infrared image reproduction: the range of CMY into CMYK transformation, CMY invisibility in near infrared light, carbon black in NIR, gray and CMY gray, and device dependency of CMYK inks. The reproduction is observed selectively in wavelengths ranging from 400 to 1000 nm. Independent graphics may be graphics generated by algorithms, conventional images or texts. Information about its visible area is joined to each graphic. Detecting graphic work incorporated differently in a print with the help of the corresponding instruments is becoming a new chapter in security graphics, design, and informatics.

We have developed a drop-on-demand printhead that can eject molten metal droplets. The capability of ejecting solder drops onto an X-Y stage controlled substrate makes this new technology ideal for fast prototyping of metallic traces on planar and three-dimensional (3D) objects. The ejection process uses the electromagnetic repulsion force between two parallel currents moving in opposite directions. One current path flows through the molten metal, such as solder, the other through a copper stripe. The electrical connection between the two conductors was accomplished by two Ni plated vias. By adding an appropriate nozzle in the solder channel, a current pulse can cause a drop to squirt out. The size of the ejected solder drop depends on the driving energy, which is controlled by both the pulse width and the drive voltage. For successful operation of the printhead, wettability of the solder to the printhead material needs to be taken into consideration. We have constructed the solder jet printhead in both a polyimide laminate stack and a ceramic form that can withstand a much high temperature. We have ejected molten PbSn eutectic solder as well as BiSn and InSn with precision on Si wafers, over substrates with different heights and connecting the traces on different levels, as well as creating freestanding 3D structures.

Ink-substrate adhesion critically impacts the print and page attributes of advanced printing technologies. Here the authors show that interfacial acid-base interaction (A-BI) plays an important role in the enhancement of ink-substrate adhesion. Successful probing of the ink-substrate interface via surface-sensitive attenuated-total-reflectance Fourier-transform infrared spectroscopy reveals intricate transient A-BI behavior, which appears to dominate the initial phase of adhesion in a printed substrate. The authors also demonstrate that macroscopic adhesion strength between an ink layer and a substrate can be correlated directly to the extent of A-BI. Their observation could potentially pave new directions for future advancement of high speed digital printing technology and could have important implications in other marking material systems.

Color Index pigment orange 13 (PO13) modified with styrene-maleic acid copolymer (PSMA) was prepared via phase separation technique. Experimental results showed that a dispersion with small particle size and high centrifugal stability could be obtained using number molecular weight (Mn) of PSMA at 22,500, the weight ratio of PSMA to pigment (RC/P) at 0.24, and pigment content (CP at 15%. The particles were small and uniformly dispersed in aqueous media. The PO13/PSMA dispersion had high stability and exhibited an improved printing performance when it was applied to preparation of ink jet printing ink.

The preparation and characterization of TiO₂ particles coated with an electrophoretic polymer using silane coupling agents and highly hydrophilic monomers (methyl methacrylate) are presented in this article. The organic layer was formed by radical polymerization and bonded to the surface of inorganic TiO₂ with a silane coupling agent. The polymer-coated particles were characterized by Fourier transform infrared spectrometry, field emission scanning electron microscopy, and thermogravimetric analysis. The size distribution and charge properties of the polymer-coated particles were measured, and the optical response of electrophoretic image display cells, containing the particles, was also investigated. It was found that coating materials having a branched alkyl side chain structure endowed the final polymer-coated particles with good stability and favorable electrophoretic properties in an electrophoretic medium. In addition, the charge polarity of the polymer-coated particles could be controlled using different silanizing reagents and polymers. Furthermore, electrophoretic image display cells, containing such particles, demonstrated good response and high reflectance in their white state.

The authors have previously reported a method for preparing gold nanoparticles using silver halide photographic materials and gold deposition development. This process was investigated from the viewpoint of the effect of thiocyanate ion concentration. Gold particles are formed on latent image specks on the exposed silver halide grains by the disproportionation reaction of gold(I) thiocyanate complex ions. The ratio A of gold ions to thiocyanate ions in preparing the gold(I) thiocyanate complex affects gold deposition; that is, the rate of gold deposition increases when the abovementioned ratio A increases from 1:10 to 1:3. Optical measurement, atomic absorption spectroscopy, and electron microscopic observation indicate that the growth rate of gold nanoparticles does not depend on the ratio A, while the total mass of gold atoms increases with an increase in the ratio A. The mass increase is due to the increase not in size but in the number of gold particles. Excess thiocyanate ions inhibit the deposition of gold atoms on latent image specks.