International Journal of Science, Engineering and Computer Technology

Satish Chauhan ¹, C. Dinesh ¹, Arohit Goyat ¹

Affiliations
1 Department of Printing Technology, G.J.U.S & T, Hisar, Haryana, IN

Abstract

In the modern era, digital printing has been dominating printing process to print on veriety of paper substrates. Electrophotography is one of the commonly used technology or method in digital printing process. The emerging trends in the field of digital printing take over the position of traditional printing processes which requires the scrutiny of the print quality parameters. The total digital controlling of the printing process gives a hypothesis of achieving the consistent print quality in all prints. This article is scrutinizing that hypothesis by conducting the instrumental (Techkon Spectro Dens Premium spectrophotometer) measurement of colorimetric and densitometric tonal values and quality parameters of the print on coated and uncoated paper which is printed on daily basis. The results show that the Delta E (colour variation) is higher in uncoated papers as compared to the coated prints. Solid ink density and print contrast of black colour has better consistency on uncoated paper and print contrast of all colours on coated are also subjected tothe variations. The solid ink density of yellow colour on coated paper shows highest densitometric value consistency.

Keywords

Solid Ink Density, Print Contrast, Delta E.

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Deepak Kumar Sharma ¹, C. Dinesh ¹

Affiliations
1 Department of Printing Technology, GJUS&T, Hisar, Haryana, IN

Abstract

In the modern era, digital printing has been dominating printing process to print on variety of paper substrates. Electrophotography is one of the commonly used technology or method in digital printing process. The emerging trends in the field of digital printing take over the position of traditional printing processes which requires the scrutiny of the print quality parameters. The total digital controlling of the printing process gives a hypothesis of achieving the consistent print quality in all prints. This article is scrutinizing that hypothesis by conducting the instrumental (Techkon Spectro Dens Premium spectrophotometer) measurement of colorimetric and densitometric tonal values and quality parameters of the print on coated and uncoated paper which is printed on daily basis. The results show that the Delta E (colour variation) is higher in uncoated papers as compared to the coated prints. Solid ink density and print contrast of black colour has better consistency on uncoated paper and print contrast of all colours on coated are also subjected to the variations. The solid ink density of yellow colour on coated paper shows highest densitometric value consistency.

Keywords

SID, Print Contrast and Delta E.

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, Kerala, IN

Abstract

The research paper aims to the analysis of light fastness of inkjet printed textile products to the artificial light. The artificial light used here is a xenon arc lamp and two polyester substrate having different screen counts is selected. The higher screen count shows less color variation to the artificial light as compared to the color variation on less thread count substrate. The ink used for inkjet printing is locally made at Flasbjet inks, Chennai and the cost is less. The artificial lights are rich in various ranges of electromagnetic spectrum especially in ultra violet region. Various researches show the UV light is responsible for 50 % light fastness, 25% by beat and 25% by normal light rays. In this research. Yellow color shows higher color variation. The solid patch color variation is higher than the tint patch color variation. Some research shows higher level multi ink layers have less color variation. The one of the main method to prevent the light fastness is the addition of cationic UV absorbers as the ingredient in the printing ink.

Keywords

Color Fastness, Artificial Light, Inkjet Printed.

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, Kerala, IN

Abstract

This article focus on the possibility for the reduction of fading of color due to the photo degradation by the action of UV light present in the sunlight. The polyester substrate was printed with prepared inks which contains UV absorbers in different quantity. This research shows the UV absorber shows an important role in the fading of color and reduction of light fastness. The different pigment has different range of light fastness.

Keywords

Light Fastness, Delta E, UV Absorbers.

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, Kerala, IN

Abstract

The tonal value increase in printing denotes the dot gain that should he considered at the time of print quality assessment. That is indirectly connected to other print quality parameters such as solid ink density, print contrast etc. Tonal value increase is higher in middle tone patches of process colors. The TVI can he considered both colorimetrically and densitometrically. The use of two cyan color inks has same tonal value but there will be an apparent hue shift. The densitomeric TVI only consider the process control and colorimetric TVI combines both process control and image appearance. The Densitometric TVI is measured in M3 mode and Colorimetric TVI is based on MO mode. This research paper shows the densitometric TVI values are higher than the colorimetric TVI. The black color patches shows higher delta TVI and yellow color patches shows lowest delta TVI.

Keywords

Light Fastness, Delta E, UV Absorbers.

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, IN

Abstract

The first color difference equation is developed by CIE (International commission On Illumination) on 1976 known as Delta E 76 or Delta E ab. Here the attributes of colors such as chroma, hue and lightness are considered in equal value or importance. That is perceptibly not suitable to the human eye. Changes in hue can easily identifiable than the changes in lightness. The color measurement committee of the society of Dyers and Colorists of Great Britain developed a new color difference equation based on the weightage for lightness and chroma difference. In 1995, CIE developed Delta E 94 where hue, chroma and lightness are specially considered by giving weightage and it gives better results. Finally most accurate color difference equation Delta EOO introduced which corrects inaccuracy in the calculation of lightness in Delta E94. This paper shows the Delta E ab or E 76 higher color differences than the other Delta E equation based color differences. The variation in Delta E 94 and Delta E 00 is very less due to the inaccurate calculation of lightness in Delta E 94. Delta E CMC l:c shows good acceptability based on the human visual perception and used in the textile industries. The ISO technical committee TC 130 accepted the Delta E2000 for color difference analysis for ISO 12647 based offset printing. Delta E 2000 will be the new industry standard by replacing the Delta E ab for color difference analysis.

Keywords

CIE Delta E 76 or E A*b*, Delta E 94, CMC l:c, Delta E94 and Delta E00.

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, IN

Abstract

The International Commission on Illumination(CIE) developed two standard observers; 2° standard observer and 10° standard observer. The standard observers application may vary based on the field of application and the viewing distance. The 2° standard observer is applicable in commercial and publication printing and 1° standard observer is applicable in packaging printing, textile and painting because it viewing distance more than 4 meters. The research show solid ink patch shows higher color variation than the tint color patches when measuring the color patches using a spectrophotometer by only changing the standard observer parameter. The color variation is not visible to human eye up to the 50 % tint color.

Keywords

2° Standard Observer, 10° Standard Observer and Delta E

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C. Dinesh ¹

Affiliations
1 Creation Offset Press, Ernakulam, IN

Abstract

Color appearance model is a mathematical models to predict the image appearance in different lighting and viewing conditions in different media. The CIE colorimetry based on CIE Lab is applicable to the system where the white point is same or no more change. Different color appearance models are developed by considering the different factors such as simultaneous contrast, hue and colorfulness, brightness and lightness, saturation and chroma etc. Each model has their mathematical calculations and their prediction may vary from other models. CIE CAM02 is accepted in overall industry. The image color appearance models shortly known as iCAM is applicable to make the prediction of more complex stimuli in wide variety of color viewing conditions. Psychophysical experimental data is one of the best methods for evaluating the different appearance models. This paper reviews the applicability of different color models for matching the images for cross media color reproduction including print media. After the adoption of CIE LAB, there evolved a plan for finding out the more precise, accurate, comprehensive and exact color appearance models due to the increased interest in the late 1980's and 1990's and the practical applications requiring appearance models has accelerated the works in this area. These great efforts have resulted in the formulation and adoption of CIECAM97s in 1997.

Keywords

Color Appearance Model, CIE Colorimetry, RLAB, Nayatani, Hunt Model, CIE Lab.

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