Generally speaking, the subjective and objective inconsistency of the color difference evaluation result of the printed color is manifested in two aspects: one is the color that the human eye can feel when the same color shifts toward the different color directions to produce the same color difference value. The degree of difference is different; the second is that when the different colors are shifted toward the same color direction to produce the same color difference, the degree of color difference that the human eye can feel is also different. For the above two points, the experimental method of display simulation can be used for qualitative explanation.
The specific process is: in CIELAB color mode, select 50% CMY tricolor and RGB tricolor and 50% ash synthesized by them, respectively change the color to change the color in a certain direction, and observe with the human eye. When the color difference can be distinguished, the size of the change value and the corresponding color chromatic aberration are different when the color of the same color is shifted in different directions. In general, the effect on vision is greatest, and the effect on vision is minimal when the color of the color changes.
This is exactly the case in actual printing. Even if the color difference is small, the darkness or shallowness of the printed product is easily noticeable. This also shows that in the color difference formula, the weight in the influence of the change on the color difference is the largest. Therefore, the evaluation of color depth has a high degree of precision in visual judgment.
The color cast of different colors in the same color direction has different effects on vision. Studying this point is important for the color detection of printed matter. Because in the printing, the color cast of the printed product is caused by too much or too little printing ink of a certain color plate, and the color cast direction is uniform. For example, if the amount of ink in the yellow plate is too much, all the colors on the printed product are yellowish, and visually, the area dominated by magenta ink and cyan ink is biased.
From the simulation results of the display, it can be concluded that in the CIELAB color mode, the objective color difference does not match well with the visual results. To achieve the unity of subjective and objective evaluation, it is necessary to analyze the reasons for the inconsistency in order to design a more A reasonable objective color difference evaluation system finally makes it conform to visual color judgment. In practice, there are three main aspects that lead to inconsistency:
First, subjective aspects affect many visual assessments, such as sample characteristics and observation conditions.
Secondly, the influence of the design and manufacturing precision of the color measurement instrument itself, when the same color measurement instrument performs multiple measurements in the same place of the solid color block, the color data may not be completely consistent, that is, there is a repetition of the color measurement instrument. Precision problem.
In addition, the color data measured by different color measuring instruments in the same place will not be exactly the same. These instrument errors can affect the accuracy of chromatic aberrations.
Third, the unevenness of the color space makes the color difference value measured by the instrument not fully reflect the visually perceived chromatic aberration. The inhomogeneity of the color space can be clearly demonstrated from the experimental results of WDWright and DL MacAdam.
MacAdam tolerance ellipse x, y is the chromaticity coordinate. The human eye has different widths for different hue colors. The green area has a large color and large capacity, the yellow area is second, and the blue area is the smallest, that is, the human eye is different in color sensitivity to different hue; The lower the brightness of the color, the smaller the tolerance range, so the dark sample is not easy to achieve color matching; the lower the chroma of the color, the smaller the tolerance range, so the color of the gray series is not easy to achieve color matching. CIE officially recommended the CIELAB uniform color space and its color difference formula in 1976. Although the CIELAB color space partially eliminates the difference of the tolerance of different color regions, the space is still uneven, and the color difference formula does not reflect the color three. The weight difference of attributes is so limited in industrial applications.
In general, the color difference results calculated by the formula are not as good as the actual ones. The error caused by CIELAB measuring instrument can not only improve the measurement accuracy by applying more scientific design principles, but also reduce the average point of the same point in the measurement process and the same measuring instrument for the same batch of prints. Small errors, which increase the accuracy and repeatability of the measurement. In order to better correct the uniformity of the color space, the instrument measurement results are better matched with the visual evaluation of the color. It is necessary to use the more advanced color difference formulas above to correct the three color difference formulas by introducing different parameter factors. The non-uniformity of the color space used (CIELAB) is conducive to the unification of subjective and objective evaluation.
Considering the complexity of the actual printing, by communicating with customers, printing companies can develop different color difference standards for different printing colors. It can be seen that the perfection of the color difference formula plays a crucial role in the objective evaluation.
Generally speaking, the subjective and objective inconsistency of the color difference evaluation result of the printed color is manifested in two aspects: one is the color that the human eye can feel when the same color shifts toward the different color directions to produce the same color difference value. The degree of difference is different; the second is that when the different colors are shifted toward the same color direction to produce the same color difference, the degree of color difference that the human eye can feel is also different. For the above two points, the experimental method of display simulation can be used for qualitative explanation.
The specific process is: in CIELAB color mode, select 50% CMY tricolor and RGB tricolor and 50% ash synthesized by them, respectively change the color to change the color in a certain direction, and observe with the human eye. When the color difference can be distinguished, the size of the change value and the corresponding color chromatic aberration are different when the color of the same color is shifted in different directions. In general, the effect on vision is greatest, and the effect on vision is minimal when the color of the color changes.
This is exactly the case in actual printing. Even if the color difference is small, the darkness or shallowness of the printed product is easily noticeable. This also shows that in the color difference formula, the weight in the influence of the change on the color difference is the largest. Therefore, the evaluation of color depth has a high degree of precision in visual judgment.
The color cast of different colors in the same color direction has different effects on vision. Studying this point is important for the color detection of printed matter. Because in the printing, the color cast of the printed product is caused by too much or too little printing ink of a certain color plate, and the color cast direction is uniform. For example, if the amount of ink in the yellow plate is too much, all the colors on the printed product are yellowish, and visually, the area dominated by magenta ink and cyan ink is biased.
From the simulation results of the display, it can be concluded that in the CIELAB color mode, the objective color difference does not match well with the visual results. To achieve the unity of subjective and objective evaluation, it is necessary to analyze the reasons for the inconsistency in order to design a more A reasonable objective color difference evaluation system finally makes it conform to visual color judgment. In practice, there are three main aspects that lead to inconsistency:
First, subjective aspects affect many visual assessments, such as sample characteristics and observation conditions.
Secondly, the influence of the design and manufacturing precision of the color measurement instrument itself, when the same color measurement instrument performs multiple measurements in the same place of the solid color block, the color data may not be completely consistent, that is, there is a repetition of the color measurement instrument. Precision problem.
In addition, the color data measured by different color measuring instruments in the same place will not be exactly the same. These instrument errors can affect the accuracy of chromatic aberrations.
Third, the unevenness of the color space makes the color difference value measured by the instrument not fully reflect the visually perceived chromatic aberration. The inhomogeneity of the color space can be clearly demonstrated from the experimental results of WDWright and DL MacAdam.
MacAdam tolerance ellipse x, y is the chromaticity coordinate. The human eye has different widths for different hue colors. The green area has a large color and large capacity, the yellow area is second, and the blue area is the smallest, that is, the human eye is different in color sensitivity to different hue; The lower the brightness of the color, the smaller the tolerance range, so the dark sample is not easy to achieve color matching; the lower the chroma of the color, the smaller the tolerance range, so the color of the gray series is not easy to achieve color matching. CIE officially recommended the CIELAB uniform color space and its color difference formula in 1976. Although the CIELAB color space partially eliminates the difference of the tolerance of different color regions, the space is still uneven, and the color difference formula does not reflect the color three. The weight difference of attributes is so limited in industrial applications.
In general, the color difference results calculated by the formula are not as good as the actual ones. The error caused by CIELAB measuring instrument can not only improve the measurement accuracy by applying more scientific design principles, but also reduce the average point of the same point in the measurement process and the same measuring instrument for the same batch of prints. Small errors, which increase the accuracy and repeatability of the measurement. In order to better correct the uniformity of the color space, the instrument measurement results are better matched with the visual evaluation of the color. It is necessary to use the more advanced color difference formulas above to correct the three color difference formulas by introducing different parameter factors. The non-uniformity of the color space used (CIELAB) is conducive to the unification of subjective and objective evaluation.
Considering the complexity of the actual printing, by communicating with customers, printing companies can develop different color difference standards for different printing colors. It can be seen that the perfection of the color difference formula plays a crucial role in the objective evaluation.
Article source address: http://
Black gas firepit is a versatile gas-burning firepit, perfect for any yard or patio and indoor. It`s easy to move from one spot to another, and it is big enough for friends party and also great for just a small family affair. This gas firepit is equipped with four pieces decorative glasses.Gas regulator from different countries can be supplied. and they all have certification for different countries. The decoration covering the flame can be high temperature resistant glass balls and volcanic stones.It is the most common heating tool in modern families. Compared with the liquid gas heaters, electric heaters and coal-fired heaters used in traditional families, it is more convenient and fast, and the safety is relatively high.In the cold winter, the temperature drops sharply, more than ten degrees below zero is very common, so a variety of heating equipment has become an essential product for people. Gas heater is a very popular heating equipment, a lot of people have in the home to buy and use. However, consumers who need to buy heating equipment often do not have a special understanding of these products. Today, we will introduce some product features and advantages of gas heaters to help more consumers buy the most suitable products when they buy gas heaters.
| Name |
Patio Portable Propane Fire Pit |
| Material | Corten steel |
| Size | 800*800*400mm |
| Steel thickness | 2mm |
| Weight | 60KG |
| Packing | Pallet/carton/wooden box packing |
Gas Fire Pit,Propane Fire Pit,Outdoor Gas Fire Pit,Gas Fire Pit Table
Henan Jinbailai Industrial Co.,Ltd , https://www.designsteelart.com