How do I make quality images before I Cover A5 Spiral Journals Notebooks

How do I make quality images before I Cover A5 Spiral Journals Notebooks

 

In the field of packaging printing, color plate printing has become the mainstream of printing. The quality of printed matter is also improving. A beautiful print quality picture, will give people a comfortable and natural feeling, make people feel as if they are in the real world. However, due to the influence of subjective and objective factors, although the quality of color printing products has been greatly improved in the past, in general, there are not many high-quality products, which cannot be compared with foreign high-quality products. There are equipment, materials and other objective factors, but the operator quality and technical deficiencies are also important factors. We know that the quality of the product in color printing is subject to all the factors involved in the reproduction process, such as the tone level, color tone and sharpness of the original color image; The accuracy of the reproducing and adjusting data, such as the tone level, color and sharpness of the screen picture; Copy, printing and other intermediate process dot conversion change and its stability; Printing (or) proofing of ink layer density, dot expansion value or printing relative contrast value data and control stability, overprinting efficiency of each color ink layer, step tone evolution, color balance and gray balance reproduction; The performance and operation of printing paper, the color characteristics of ink and its operation; The printability of the equipment, equipment and materials of each operation process, the quality of the process operation and the adjustment data of the copy object and many other aspects.

 

Among the above influencing factors, the quality of prepress image production directly determines the quality of color printing products. Therefore, when making images before press, if the quality of the original manuscript is not good, we should try our best to correct and improve it, so as to ensure the high quality of printed matter. Due to the current production of the original manuscript, most of the existence of some deficiencies, prepress production personnel without a high level of technology, without a good artistic aesthetic, to produce high quality products is difficult to do, the following is a brief introduction to some prepress image production of the original manuscript quality defects when processing technology and methods.

 

The method to deal with the problem of original tone level

 

Color paintings, prints, photographs and other reflection manuscripts, the level density contrast is close. The overall density and level contrast of color transmission manuscript is larger. Generally speaking, the density contrast in 1.8 ~ 2.4, for the normal manuscript, greater than 2.4 for high contrast manuscript, less than 1.8 for low contrast manuscript. The initial density was 0.3 ~ 0.5 as normal draft; If it is higher than 0.5, no matter how the contrast is, it is caused by insufficient exposure (or development), which is boring manuscript; The contrast is lower than 1.6, and the initial density is lower than 0.3, is caused by excessive exposure (or development), is weak manuscript.

 

The overall density and contrast of the color transmission manuscript are closely related to the lighting conditions, exposure and development processing of the original manuscript. The position of the image on the sensitive characteristic curve is different, and the difference of the density contrast of each layer is also changed, and the distribution state of its layers is different. For photographic art originals, the aesthetic adjustment lies in focusing on the impression color and visual effect, emphasizing the contrast effect of pictures, highlighting the sense of light, emphasizing the color saturation, exaggerating and rendering the important colors in the picture, and highlighting the visual impact of colors. It is necessary to emphasize to make up for some deficiencies in the process of shooting and developing, adjust and deal with the relationship between color shadow, light and shade, cold and warm, space color change in the photography art, and highlight the styling effects such as tone, atmosphere, light and shadow, texture of photography pictures. Make the manuscript production with a strong sense of light, bright highlight, dark intensity, give people feel the beauty of light and shadow; With strong color saturation, bright color, rich color changes, give a person with color art appeal; It has high definition, clear texture of scenery, delicate particles and rich fine layers, giving people a sense of reality. In the actual production, due to the dark tone of the photographic picture is easy to bias color, resulting in the object black is not pure. Therefore, the application of UCR/UCA function for correction, so that the three primary color version to achieve neutral black effect, and then black version mainly, so as to achieve black pure effect, better show the texture of black objects.

 

It is impossible to copy the original manuscript absolutely faithfully, because most of the density contrast of the original manuscript is greater than the density contrast of the printed matter, so the printed matter reproduction must compress the density. Therefore, it is necessary to lose part of the fine level, in actual operation should be based on the contrast of the original manuscript and the specific content of the tone, adjust the reasonable level curve, that is to say, whether it is the reflection manuscript, or transmission manuscript above the secondary part of the level of compression, so that the main part of the level to focus on, characteristic emphasis. [next]

 

Under the premise of normal contrast of color manuscript, adjust the level curve correctly according to different types of manuscript. But we must pay attention to the balance of the level curve of the color separation film, neutral gray balance should be appropriate, incorrect level curve will cause the reproduction distortion. For the original manuscript color bias, generally can be corrected by adjusting the level curve. For the manuscript with different levels of density and quality, the following methods are often used to deal with the compression of the step tone contrast of the manuscript.

 

(1) Normal exposure, density contrast standard. Its main parts are in bright tone and medium tone, which is proportional to the brightness, belonging to the best visual brightness range, in the brightness of the new scale system of 4 ~ 6, this kind of original manuscript black and white field calibration according to the standard density value, then all the information on the original manuscript light and medium tone can be reproduced on the scanning color separation film. The normal manuscript, its contrast is moderate, should make the low-key level compressed flat, especially to emphasize the middle and bright tone level, it is more appropriate.

 

(2) medium contrast manuscript. The low density is 0.3 ~ 0.5, the high density is 2.4 ~ 2.8, the contrast is normal, close to the standard manuscript, the image of high and low level can be shown in the straight part of the sensitive characteristic curve, the middle tone level is rich, the main level is in the medium bright tone, the level density grade is proportional to the original scene, the tone is generally normal, in the original manuscript tone contrast compression, Good reproduction effect can be achieved by adjusting the level according to the level reproduction curve close to the standard. Because of the different distribution state of the level of the original manuscript, the level of the reproduction curve of the same contrast manuscript should also be different. If the manuscript is clear, the subject tone is in the range of bright tone, and the copy should be deepened slightly to meet the visual response. If the strong tone manuscript, the main tone is often in the range of density, should not deepen the copy. Reflection (except photographs) level reproduction curve can be between the above two. For the original contrast is basically suitable for printing and copying, with intermediate tone mainly photos, dark tone area is small, you can compress the dark tone level, so as to emphasize the intermediate tone level.

 

(3) high contrast manuscript. The highlight density is not higher than 0.4, and the highest density is above 3.0 of the original manuscript, most of the original scene contrast contrast is too large, the general level of the middle level is rich and complete, the brightest and darkest level area ratio is not large, generally not the main level, but high, low density jump, increase the contrast. In this kind of manuscript, when making the highlight and dark selection, the secondary level at both ends can be omitted to reduce the scale of its copy. Its level reproduction curve can be adjusted according to the different level distribution curve of the image.

 

(4) low contrast manuscript. Tone contrast below 1.7, highlight density below 0.3 light tone of the original manuscript, mostly due to overexposure or excessive development. The main part of the bright and thin, high brightness, in the brightness of the new standard system 7, 8 level, bright tone most levels fall on the shoulder of the negative image characteristic curve, bright tone level is rich, but the density level difference is very small, and accounts for a large proportion of the area. Production to deepen the copy, to reduce the brightness, close to the standard brightness. This kind of manuscript needs to strengthen the hierarchical copy and redistribution of bright and medium tone, and the density value of black and white field calibration should be smaller. The hierarchical curve of bright and medium tone should be slightly deepened to achieve better hierarchical contrast and visual brightness effect. According to the shape of its hierarchical distribution curve, its main tone should be distinguished in light tone or medium tone density range. At the same time, it is also necessary to use deepened and lengthened black tone to supplement, so that the intermediate tone level of the reproduction picture is deeper than the level distribution of the original manuscript, to meet the artistic requirements of visual psychology on the picture. If the color photo manuscript is thin and the contrast is small, you can compress the light and dark tone layers to make the contrast of the middle tone layers greater.

 

(5) thick stuffy manuscript. Due to insufficient exposure or development, most of the dark level of the image falls on the toe of the negative characteristic curve and the lower half of the straight line. The original contrast is thick and stuffy, the whole picture is larger in low-key area, and the bright tone is flat. If the emphasis is on opening the dark and middle tone level, the middle tone level will appear flat accordingly. For the original medium tone level is relatively flat, the contrast is small, you can compress the bright tone level, make the medium tone level more contrast.

 

The main part of the thick manuscript is dark and deep, in the brightness of the new standard system of 2, 3 level, light tone level is less, dark tone level is rich and the level is soft, and the area ratio is large, the main tone also falls in the range of density adjustment, production to reduce the shallow and improve the copy, in order to brighten the brightness, close to the standard brightness. In the reproduction of this kind of manuscript, the density value of black and white field calibration should be larger, the level curve of medium and dark tone should be slightly reduced, and the level of medium and dark tone including the main tone should be more bright, so as to make the picture clear, and also emphasize the level difference of medium and dark tone, so as to achieve better tone contrast and visual brightness effect.

 

(6) Intermediate level distribution of different manuscripts. Some manuscripts with medium and high density contrast have fewer medium tone levels and larger density difference, while high and low tone levels are more gentle and gentle. For example, color films shot in backlight, the production should try to make the level of light and shade of the main tone of this kind of image coordinate, so as to achieve better reproduction effect. [next]

 

The size of the image level contrast can be adjusted by compression of the density range when copying, and the initial density can also be changed by adjusting the highlight density setting and recording setting. However, whether the hierarchical distribution of the original image can meet the artistic requirements needs to be redistributed while the hierarchical contrast compression is carried out in the reproduction. The description and analysis of the hierarchical distribution of the original manuscript is very important to the redistribution and adjustment of the hierarchical copy, which is the primary basis of the hierarchical copy. When printing matter is restored in tone, it is generally necessary to adjust the tone. When the density contrast of the original manuscript is greater than the highest recorded density of the printed matter, in order to make each tone of the original manuscript can be shown in the printed matter, it is necessary to adjust the tone to the original work properly. Secondly, in order to adapt to the reproduction requirements of some special manuscripts (such as: light tone photos, dark tone photos), it is necessary to properly emphasize some tones of the original manuscript, and compress other tones accordingly. The main feature of linear compression is the adjustment of the equal proportion of each level of adjustment, linear compression does not represent the real visual equal proportion compression, because D-Y curve is also nonlinear, after this compression, bright adjustment is not easy to be identified by the human eye, resulting in "gray flat" phenomenon. Tonal reproduction refers to the relationship between the density of the manuscript and the percentage of copied points. In order to make all the harmonic colors on the original manuscript can be well displayed on the print, first choose the correct level curve. Level is the basis of step and harmonic color change, if the level of the picture is not rich, the performance of color is also bound to be monotonous, only realistic level, can have vivid color change.

 

Transmission of natural color positive film contrast range difference is relatively large (about 3.0), usually need to compress the contrast, to meet the requirements of print copy; And reflection manuscript contrast is small, manuscript dull, according to the characteristics of different manuscripts bright copy. For example, the key point of the reproduction of the portrait is the skin color of the figure, M, Y two color is the key; Landscape picture reproduction focus on natural scenery, C, Y two color is the main point. Flexible use of the level knob, adjust the reasonable level curve, correct the deficiency of the original manuscript, maintain the main part, the corresponding loss of the secondary part, bold choice, as far as possible to copy a better effect. However, if the level curve adjustment is not reasonable, it may cause the picture to reverse the primary and secondary, the level is not clear, the color is not correct. Since color prints should be reproduced as a picture with a basically consistent density range, which is mostly lower than the density range of the color manuscript, compression adjustment must be made in the process of color separation and plate making. On the one hand, the redistribution and adjustment of each tone level depends on the level distribution of the original manuscript, and on the other hand, it is related to people's visual perception. Among them, there are Munselming value factor of visual response and subjective factor of people's visual psychological requirements. To copy and adjust the level of tone of the original manuscript, it is necessary to comprehensively sum up people's visual psychological needs, add the physical value of visual response, and consider the level distribution of the original manuscript to obtain the density level of tone level reproduction curve of the printed picture. Then, by incorporating the evolution data in the process of replication and reproduction, the level of tone reproduction curve of the specific original manuscript can be designed.

 

The density range of printed matter is large, which can not only reproduce some levels of the original manuscript or original scenery, but also make the contrast between levels open some, three-dimensional sense is strong. In particular, it can enhance the subtle level contrast, but also enhance the definition of the image level. On the other hand, it also makes the color of the picture open the level, making the deep saturated, the light clear, enhance the three-dimensional sense of color. However, the increase of the density of the printing ink layer is contradictory to the increase of the dot, and it is impossible to reach the high density of the color transparent film. Only in paper, ink, equipment adaptability and printing press precision and other excellent conditions, to have a lower dot increase value and higher ink layer density.

 

Therefore, the objective technical standard to determine this quality index is to use color reflection densitometer to measure the printing field density and 75% dot printing density of each printing ink layer, and calculate its printing K value. When there is a high printing K value (yellow version 0.3 ~ 0.4, magenta and green version 0.4 ~ 0.55, black version 0.5 ~ 0.6), their respective field density is high, and the overprinting efficiency of each color ink layer is close to 90%, the printing scale is better. Such a printed matter is bound to be a picture with distinct layers, strong, full and three-dimensional sense. In order to save printing ink, some people advocate reducing the density of printing ink layer to reduce the increase of dot. That way, although the expansion of printing dot level is less, reducing the phenomenon of the level of the dark tone end of the image, but the overall level contrast is not the highest, and can not reach the best printing level level reproduction.

 

Since the printing process level is nonlinear transfer, compensation adjustment should be made before printing. In the transmission process of printing and printing technology, it is limited by various conditions, and the transmission of the dot level is nonlinear. In order to adapt to the printing process, compensation adjustment must be made. The key is to print the three dot jump area, also known as the three key areas for adjustment, namely 3%, 50%, 80% dot area. Because 3% small points are easy to lose, it will affect the color level of the highlight area, 50% dot area is easy to increase, it will affect the middle tone, especially the change of people's skin color, 80% dot area is easy to grade, it will affect the level of dark tone, especially the main color of dark tone and the depth of the primary color, so that printing is difficult to take into account both, often confused. Therefore, for some of the important color, important parts of the original manuscript, by adjusting it to avoid the three dot jumping area, so as to provide the ideal printing plate for printing, so that it is good to print, print a good product. [next]