Study on Printing Quality of Different Kinds of Paper by Ink Jet Printing (12)

(ii) Analysis of LCH and paper properties at various RGB concentrations

1. Analysis of Lightness by printing results on the 1st and 2nd printers: In the concentration range (0% whitening ~ 100% pure color ~ 50% darkening), the lightness (lightness) on the opacity of paper properties, white The degree, gloss curve of Red, Green, Blue show a positive relationship, when the opacity, whiteness, gloss increase when the brightness increases. In the concentration range (0% whitening to 100% pure color), the concentration of the curve concentration in each region of RGB is roughly the lower the concentration is, the higher the concentration of the curve is in the region with higher lightness (lightness). In the concentration range (0% darkening to 100% pure color), the concentration of the concentration of each region of RGB is roughly the concentration of the lower concentration to the region where the Lightness (brightness) is lower.

2. The results of the printing on the 1st and 2nd printers are analyzed for Chroma (chroma): In the concentration range (50% whitening ~ 100% pure color ~ 50% darkening), Chroma (saturation) does not correspond to the nature of the paper. The curves of transparency and whiteness show a positive relationship between Red, Green and Blue. When the opacity and whiteness increase, Chroma increases. Glossiness is less obvious in the performance of Chroma (chroma), the curve change is less regular, and due to the change of its own glossiness is difficult to control in this experiment, it cannot be judged with the Chroma (chroma). relationship. In the range of 100% (solid) to 0% (whitening or darkening), the concentration of the concentration of each region of RGB is approximately the concentration of the region where the concentration is lower and the chromatogram is lower. (As shown in Figure 4-21 ~ Figure 4-26)

3. The results of Hue (hue) are printed on the printers of No. 1 and No. 2. The Hue (hue) has a linear change in the density, whiteness, and glossiness of the paper properties and does not constitute a correlation. . Overall Data Analysis Hue (hue) has no influence on the opacity, whiteness, and glossiness of the paper properties at all RGB concentrations.

Wu, conclusions and recommendations

This experiment uses different types of paper, first measuring the whiteness, opacity, and gloss of the paper, then printing with two different technology inkjet printers, using the instrument to measure the LAB (calculate the difference) and the LCH value, respectively. The data chart is used for discussion. After discussion and analysis, the following conclusions can be drawn:

1. In terms of chromatic aberration, the higher the paper's opacity and whiteness, the smaller the color difference, and the lower color difference values ​​are concentrated on the A and B papers. Therefore, the A and B paper ratios are displayed. D is better.

2. The color difference (No. 1 printer) has a smaller color difference and the color difference (No. 2 printer) is higher in terms of color difference statistics.

3. In terms of LCH, the opacity and whiteness in CMYK are the ones that most affect C (saturation) and the range from 25%-100% (CMY tristimulus) are proportional, that is to say, opacity, The higher the whiteness, the higher the chroma.

4. In terms of LCH, the opacity and whiteness in RGB are most affected by C (saturation) and range from 50%W (whitening) to 100%-50%B (blackening) (RGB). Tri-color), that is, the higher the opacity and whiteness, the higher the chroma.

5. Based on the experimental results (No.1 printer) and (No.2 printer), the opacity and whiteness in LCH are the most influential to C (saturation). There is not much difference in the results in this respect. .

6. Under the premise of the three items set in this experiment, the glossiness in the LCH does not significantly affect the data.

7. Based on the experimental results, although most of the results are revealed by opacity and whiteness, C (saturation) is the most effective, but there are some special cases, and the curves may fluctuate at 0% - 5%. Phenomenon, this may be the reason that we cannot master, and it is also outside of the list of causes listed in the experiment.

8. The conclusion drawn from the experiment in this paper is that as long as the paper can increase the value of opacity and whiteness, the chroma can also be improved. Therefore, whether it is RGB or CMYK, the three factors of paper change are most closely related to opacity, whiteness, and saturation.

Because the scope of the experiments done in this article is limited and cannot be done for all the properties, some suggestions are provided so that those interested can continue to study.

1. The type and nature of the papers targeted by this study are limited. It is recommended that a variety of papers and different properties be explored.
2. The types of printers targeted by this study are too few. It is recommended that you try different technologies for printers.
3. Different color difference formulas can be used to calculate whether there are differences in different formulas.
4. In-depth discussion of the printer engine and computer control software.

Source: Graphic Arts