Six key points for packaging bag manufacturers to achieve accurate color correction

In the gravure printing process, accurately replicating colors is difficult. Firstly, color is a very subjective thing, with each customer having different opinions and requirements. Secondly, due to the mismatch between the original color, screen color, digital proof color, and gravure ink proof color, coupled with the large gray scale and color deviation contained in the three primary color inks of gravure printing, the desired color cannot be fully configured.

Therefore, to print universally recognized exquisite packaging bags, packaging bag manufacturers need their own unique color correction methods and key points. Today, Shunxingyuan Packaging, a professional flexible packaging manufacturer, will share its rich printing experience to explain how to achieve accurate color correction for packaging bags.

I. Emphasize color saturation

These products require the following methods and key points.

1. The basic primary colors in the picture should be sufficient, especially the important solid deep red. For 100% solid proofing and printing products, the ink layer should be thick and substantial.

2. When electronically engraving the roller, M The color plate should use 30 ° or 37 °, which makes inking easier.

3. During engraving, deepen the cells slightly to increase the ink content, highlighting the concentration of red to meet customer requirements.

4. For large-area, high-requirement solid deep red, the double engraving method can be used to highlight the special effect of deep and bright red.

II. Properly handle the colors in the two dot jump areas

1. Properly handle 80% the colors in the dot jump areas

According to the rules of dot enlargement in engraved gravure rollers and OPP film proofing and printing, 80% the area is a dot transition jump area, 80% the above dots increase linearly, and the color layers are easily merged. 80% The dots below increase more gently, and generally, layers can be printed.

Therefore, the key to color handling here is to separate the deepest basic primary red from the medium-dark 80%~85% orange-red, flesh-colored, tea-colored, etc., composite colors. It is best to separate them by 20%~25% ，that is, the solid deep red is 100%, and the medium-dark orange-red, flesh-colored, tea-colored, etc., composite colors are reduced to 80% or less, to avoid 80% this dot jump area. On the one hand, this ensures that the solid deep red is printed sufficiently during proofing and printing.

On the other hand, it prevents the medium-dark orange, flesh, tea, etc., composite colors from appearing red, achieving the best of both worlds.

2. Properly handle 5% the colors in the dot jump areas

According to the rules that small dots are easily lost due to engraving rollers, and the transferability of small dots in OPP film proofing and printing is poor due to thin ink in high-light areas, 5% the dots below cannot be printed, resulting in insufficient ink in the high-light light color tone, and easily merging with the ultra-high-light meshing part.

Therefore, the basic colors in the high-light area should be consciously deepened and adjusted to separate them from the ultra-high-light area, making the high-light bright color tone full.

III. Emphasize color brightness

Packaging products emphasize the visual effect of color and require bright colors. Therefore, bright and bright-medium vivid colors should be composed of primary and secondary colors as much as possible, without or with moderate use of complementary colors, making the colors vivid and bright.

IV. Properly handle the continuous transition tones of real object colors

When performing color correction and adjustment, attention should be paid to both the light and dark changes in the tone and the continuous transition tones between the dark tone and the medium tone, and between the highlight and the bright tone.

The particles are rough, mainly manifested in the 80% dot area tone jumping to the deeper part, disconnecting from the intermediate tone, 5% the dot area tone jumps to the lighter part, disconnecting from the bright tone area, resulting in a rough, hard texture.

Therefore, when correcting and adjusting the colors of oranges, apples, tomatoes, and green vegetables, the tones should be naturally connected, especially the main color plate, such as the warm-toned M plate and the cool-toned C plate, to maintain continuous transition tones.

V. Properly handle the colors of external data files

Currently, more than 60% of the originals for gravure plate making are external electronic files designed by advertising companies. Because their image scanning separation uses GCR process separation mode's long-tone black plate, while the gravure printing process of packaging bag products uses a short-tone black plate process mainly based on three primary colors.

Therefore, the GCR color data of external data files needs to be adjusted to color data mainly based on three primary colors. Three adjustment methods should be mastered for this type of file.

1. Reduce the ink amount in the dark tone of the image to separate it from the black characters outside the image. Use Photoshop 's Selective Color correction tool, select Black color, reduce the ink amount of the black plate from 95% -100% to 70% or so; deepen the C plate from 60% or so to 90% -93%, and M 、 Y plate from 55% or so to 80% -83%

2. Shorten the black plate's tone, using Curve tool, shorten the highlight endpoint to C plate's 40% or so. Use Curve tool to appropriately deepen complementary colors in the image. Because GCR the process uses black to replace complementary colors in the image, reducing the ink volume of the black plate and shortening the tonal range will affect the color layers, so some compensation is needed.

3. Deepen the insufficient saturation in the dark tones caused by black replacing complementary colors. Method one is to first use the lasso tool to select the dark parts of the apple, feather the edges, and then use Curve tool to deepen. Method two is to use the magic wand tool to deepen, achieving the effect of increasing the saturation of the dark parts of the red apple.

Six, Color Adjustment Notes

1. Color adjustment should be performed after adjusting layers and correcting color casts, because changes in the tonal curve's gray balance and color cast correction will affect color changes, which is often overlooked.

2. Color correction is interrelated. When using Photoshop and other color correction tools for adjustment, the correction amount should not be too large, otherwise it will cause a series of problems.

For example:

will affect adjacent colors, causing confusion, and as a result, problems often cannot be correctly analyzed and identified.

Over-adding color to bright red in the M plate will cause excessive M color in purplish-blue and brown. For example, if Y the plate over-adds color to yellow, it will cause excessive Y color in bright red and green.

Therefore, do not only focus on correcting a certain local hue and forget to consider its interrelated color changes. If it doesn't affect other colors, bright red and yellow should be selected and adjusted separately.

will cause the leveling of layers in highly saturated primary colors.

3, Photoshop Color Correction Tool Hue/Saturation， Color Balance ， Selective Color is mainly used for adjusting primary (first) and secondary (second) color parts; do not use it to correct tertiary colors.

The Curve tonal curve is mainly used for deepening and lightening gray, tertiary colors, and overall color density, as well as correcting color casts. Do not use it to adjust colors; their properties are different, and so are their adjustment focuses.