An Evaluation of the Effect of Instrument Geometry on Color Management for Printed Textiles

The present study analyzes spectrophotometers with two different optical geometries, namely unidirectional 45° instruments and spherical 8°instruments, for building ICC profiles of inkjet-printed textiles. Unidirectional 45° instruments are utilized extensively in the graphic arts, while spherical 8° instruments are more commonly used in the textile industry. One limitation to using spherical 8° instruments for ICC profiling is that profiles built of printing conditions typically require readings of hundreds of patches, and there is only one known instrument configuration that can automate this process, while choices abound for automated instrumentation with unidirectional 45° for ICC profiling. Using a ColorScout A+, a robotic x,y table that is instrument agnostic and able to accommodate both handheld unidirectional 45° instruments and spherical 8°instruments in automating multiple readings, profiles are built and analyzed for two different inkjet-printed textile substrates

Evaluation of Light Measurement Instruments

The International Standards Organization (ISO) defines standards to ensure that viewing conditions are consistent when evaluating printed samples through ISO 3665 (2009), Graphic technology and photography – viewing conditions. The need for this standard stems from the necessity for human visual assessment as the key arbiter of the quality of complex images, and the tendency for various lighting conditions to shift the appearance of a color, specifically in relation to other adjacent colors. Among the conditions specified by ISO 3665 (2009) are Correlated Color Temperature (CCT) and Color Rendering Index (CRI). CRI is expressed as CRI Ra, with Ra representing the international standard for CRI as defined by CIE 13.3-1995. Both CCT and CRI Ra are quantifiable by a range of instruments, including traceable Spectroradiometers specifically designed for the purpose, general-use Spectrophotometers that can read CCT and CRI Ra, and handheld instruments designed for photographic applications that measure CCT. The present study seeks to compare readings from a traceable Spectroradiometer with those from various other meters across a range of seven viewing booths, some of which are known to be out of specification. The goal is to ascertain how much variance can be expected when using these varied meters when compared to a traceable benchmark instrument

An Analysis of M0 and M1 Measurement Conditions

The increased use of optical brightening agents (OBAs) in substrates for printing is well documented, as are the complications surrounding spectrophotometric color measurement when OBAs are present. In an effort to better address measurement of OBAs, the International Standards Organization (ISO) has published ISO 13566:2009, where the illuminations utilized in spectrophotometric instrumentation is more clearly defined than in previous standards. It is recognized that moving ahead the illuminant utilized in spectrophotometers should be able to better correlate to standardized viewing conditions, including the amount of ultra-violet (UV) present in the illuminant, as the effect of the OBAs is dependent on the amount of UV. Of particular note, ISO 13655:2009 recognizes measurement condition M0 as a \u27legacy\u27 condition, representative of the wide range of spectrophotometers utilized in the field. Condition M0 instruments illuminants correspond to illuminant A, while measurement condition M1 specifies that that the instrument illumination corresponds to D50, which is better correlated to standardized viewing conditions and has a more clearly defined UV component. One goal of M1 is to achieve better agreement between various manufacturers and models of instrumentation. While M1 instruments are being utilized more and more frequently in the field, there is a large population of legacy M0 instruments also in use. For those interested in understanding the variation that can be expected in the comparison of various instruments, the question of how much variation can be eliminated through the exclusive adoption of M1 instruments is especially germane

Metrology for 3D Printing: Assessing Methods for the Evaluation of 3D Printing Products

The three-dimensional (3D) printing industry projected to be $67.4 billion in 2015, double from the 2010 value, and this it is expected to grow to nearly$108 billion by 2020 (Blum & Smithers-PIRA 2105). As 3D printing technologies are frequently used to manufacture interchangeable parts and for applications such as rapid prototyping, it is little surprise that a growing body of research has examined the accuracy of these devices (e.g. Ostrout, 2015). It is customary for these studies to utilize digital microscopes together with appropriate imaging software to analyze and quantify the unique nature of 3D printed samples. It is recognized that such microscopes are generally rather costly, and are not especially intuitive to use. An alternative to digital microscopes would therefore be welcome, such a solution would need to be capable of measuring not only length and width (x and y directions), but also in height (z direction). One measurement technology that could be utilized for measurement of 3D printed products is the Flexographic plate meter. Although these meters are designed to measure flexographic relief plates, there is a possibility that they could be utilized to measure 3D printed products, as well. The present study examines and compares digital microscope technology with a commercial available flexographic plate meter. Specifically, a Keyence VHX-2000E digital microscope (VHX) is compared to a BetaFlex Pro plate meter in 3D printing applications by reading the same 3D printed samples and examining the subsequent data using descriptive statistics and a Gage Repeatability and Reproducibility (R&R) study

Lender Liability: The Legal and Management Effects on the Hospitality Industry

With the savings and loan crisis and the tail end of a recession at hand, the \u2790s are bound to be a difficult decade for the financing of hospitality operations through borrowing from commercial lenders. The authors discuss one of the least known dangers associated with borrowing, lender liability. The issue is discussed from both a legal and managerial perspective

Color Studies Curriculum: Re-Envisioning Josef Albers’ Interaction of Color in the Digital Age

The present study considers the possibility of using digital technologies to improve established color studies teaching methods, which are largely based on visual evaluation. Experiments utilized in this study are based on work outlined in Josef Albers’ Interaction of Color (2009). Albers, a famous artist and art educator, has made significant contributions to the field of color studies. In this paper, the researchers conduct two experiments to assess the efficacy of two different approaches to Albers’ traditional methods of color studies pedagogy by seeking to replicate examples from Interaction of Color. In the first approach, modern ICC-profile-based color management tools are used with an inkjet printer to determine if two illustrations featured in Interaction of Color can be faithfully reproduced. In the second approach, color measurement technologies are used to ascertain if colorimetry can be useful in selecting optimal paper samples from a set of Color-aid papers, a collection of 314 screen printed papers especially utilized by students studying color in curricula prescribed by Albers. The illustrations selected from Interaction of Color for the study are based on the visual phenomena described as ‘Two Colors as One’ and ‘One Color as Two’; these phenomena are otherwise termed ‘simultaneous contrast’ (e.g.: Long, 2015; Fairchild, 2005, Berns, 2000). The results of this study reveal limitations of these digital methods as compared to visual evaluation when replicating the visual effects of illustrations from Interaction of Color and provide insights that may enhance future curricula in color study fields

An Investigation of Factors Influencing Color Tolerances

Tolerance is the permissible difference between sample measurement and the aim and is used to determine the acceptability of a product. A well-known example is the color tolerance of printed solids in ISO 12647-2. The first edition of ISO 12647-2 was published in 1996. It has gone through two major revisions. In the 2004 revision, the magnitude of the color tolerance (∆E*ab) was changed. In the 2013 revision, a new color tolerance metric (∆E00) was included. No justification was found regarding the ISO 12647-2 revisions. In this research, %Pass is used to study the effect of color tolerance in a database. Recognizing that tolerance is a man-made decision, if the tolerance is too tight, the %Pass will be low; and vice versa. This research also examines the use of the equal %Pass to determine the tolerance equivalency between the old (∆E*ab) and the new (∆E00) parameter. The results show that there is no convergence between ∆E*ab and ∆E00 when using the boundary data approach. However, there is an equivalent tolerance between ∆E*ab and ∆E00 using the equal %Pass approach. The current ISO 12647-2 standard, using 3.5 ∆E00 for CMY and 5 ∆E00 for black, resulted in unequal %Pass. By using the equal %Pass approach, the black solid tolerance does not need to be different than cyan and magenta solids, but the yellow solid tolerance can be smaller than cyan and magenta solids

The Effect of OBA in Paper and Illumination Level on Perceptibility of Printed Colors

A research was conducted to study the perceptibility of color difference of color pairs, caused by OBA differences in paper substrates, and its relationship with quantitative measurement metrics. Based on the psychometric experiments conducted, the results show the utilization of the visual difference index (VDI), from 0 (no difference) to 3 (noticeable difference), to rate 27 color pairs with each pair prepared by the same colorants but different OBA amount in the substrates. The findings indicate that (a) printed colors are affected by the presence of OBA from no difference to noticeable difference, (b) ∆E00 has a stronger linear correlation with visual color difference than ∆E*ab does, (c) there is no significant association between illumination levels and visual color difference. This research introduces the metric, OBA, per ISO 15397 (2013), as the CIE-b* difference in color pairs under M1 and M2 conditions. It also defines ∆OBA as the OBA difference between any color pairs, including substrates. The results show that there is linear correlation (1) between visual difference and ∆E00 which describes the color difference, and (2) between visual difference and ∆OBA which describes the criticalness of M1 lighting to realize the color match