Making color samples in the laboratory is an important link in the dyeing production process. Whether the dyeing process formula is reasonable will directly affect the passing rate of dyeing samples, and is related to whether the dyeing production in the workshop can proceed smoothly and the quality of the dyed products. Can meet customer requirements and directly affect the economic benefits of the enterprise.
Therefore, this puts higher requirements on the technicians working on color matching and proofing.
Color-matching proofing ability requirements
Color-matching proofing is a technical work, and its proofing speed and proofing The sample rate of large and small samples mainly depends on the accumulation of basic information and experience of color matching sampling technicians.
1. Knowledge base
As a technology for engaging in color matching and proofing work Personnel should master the basic principles and methods of dye color matching, the properties of dyeing materials and textiles, especially the color characteristics and basic properties of the dyes used (shade, strength, color fastness and lifting power of the dye, etc.). We must have sufficient understanding of the mixing effects of the three primary colors of dyes, so that we can correctly select dyes, quickly and accurately match colors, proofing, lofting, and put them into production. There are many such basic knowledge questions and answers that you can refer to in No Borders.
2. Training of basic abilities
For a beginner, The dyes used can be used for single-color dyeing proofing according to a certain concentration gradient, and a series of single-color sample cards can be made, from which the law of the color change of the dye with the dyeing depth can be found, and the dyeing properties of the dyes used can be mastered.
Basic training is mainly divided into three steps:
Dye single-color sample card production, color triangle, and subtractive color mixing.
The purpose of making single-color sample cards of dyes is to grasp the color characteristics of the dyes used, namely:
Shade, strength, Lifting power and the change of color light with dyeing depth when using dyes.
When making the three primary color color matching pagoda diagram, first select a certain concentration of the three primary color dyes, and draw them from the three primary colors of the isosceles triangle. corner, along the three sides of the triangle, the concentration gradient decreases or increases according to 10 ok. Calculate the dye formula for each sample, a total of sixty-six samples, and proceed with dyeing and proofing. As shown in Figure 1.
Color Triangle (Pagoda Picture ) Example
By learning this method, you can initially master the color matching principles and methods of three primary color dyes, and master the basic methods and techniques of color matching proofing.
In actual work, strictly distinguishing whether a specific color mixing is additive or subtractive can improve the efficiency and quality of color matching. In color matching proofing we use subtractive color mixing.
Subtractive color mixing is shown in Figure 2.
Color proofing General Principles
Definition of color matching:
Laboratories should make samples according to incoming samples, determine the prescription, and ensure the compatibility of dyes Under the premise, different dyes are mixed in a certain proportion.
There are generally two methods of dye color matching:
One is to adjust by adding similar colors and a small amount of other dyes, that is, non-three primary color matching color.
In addition, it is mainly composed of the three primary colors, with some special colors, such as green, black, brown, etc.
1. Non-three primary colors color matching
Traditional color matching view It is believed that in general, one should try to avoid simply using primary color dyes for color matching.
If the required color is a tertiary color, use tertiary color dyes, or use tertiary and secondary color dyes.
This idea is based on the harmonious use of colors as the guiding principle, in order to achieve stable reproduction of color in production.
Three colors that are not the three primary colors, such as red + orange + green, yellow + green + gray, dark brown + yellow brown + black, etc., because each secondary color or tertiary color The increase or decrease in the amount of color dyes will increase or decrease the proportion of the second or third primary color components, which will slow down the adjustment of color light and hue, resulting in a milder possibility and amplitude of change, thus improving the stability of the color.
This method is particularly popular in the wool spinning industry.
2. Color matching of three primary colors
With the development of science and technology , especially electronic technology and optical technology have entered the field of printing and dyeing, which has greatly improved the control precision and accuracy in printing and dyeing production.
The traditional view of color matching has been strongly impacted, and the modern view of color matching has gradually become dominant. The modern view of color matching emphasizes the opposite use of colors, and achieves stable reproduction of color in mass production through high-precision control., including accurate reproduction of small and large samples.
As a result, the three primary colors color matching came into being. The characteristic of three primary color color matching is that each primary color dye has a dominant position in the hue and light, so the change range is large, the reflection result is sharp, and the variation is violent.
(1) Selection of the three primary colors:
From a pure colorimetric perspective, the three primary color dyes should be magenta and yellow. , green three kinds.
However, the selection of dyes should consider the matching of dyeing process conditions, such as temperature, time, and pH value adaptable range. Whether the process requirements such as dyeing rate and liquor ratio are the same. Whether the solubility, compatibility index, fastness, blending compatibility, finishing process conditions, etc. are similar. Under the above conditions, considering the purity of the primary color, the purer the better.
However, subject to various conditions, sometimes some non-mixed dye varieties of a single compound with a very broad absorption spectrum peak are secondary colors or even dyes from a colorimetric point of view. It is a tertiary color variety and can also be used as a primary color.
Sometimes when there is an irreconcilable conflict between the hue and color requirements and the process conditions, the hue and color requirements must be obeyed.
For very bright secondary colors, if there are no very pure three primary colors of this type, you need to prepare yellow light red, blue light red, red light yellow, blue light yellow, red light blue , yellow light blue. This does not mean that once the three primary colors are selected, everything will be fine.
Like the S-type three primary colors in disperse dyes, since each of them has some of the three primary colors, but the content ratio is different, only the tertiary color type can be used.
Dark, medium and light colors should have their own combinations of three primary colors. It is not enough to choose a set of three primary colors for each type of dye. According to the characteristics of the dye and fiber, the three primary color combinations should be selected separately from various aspects such as level dyeing, color yield, covering property, reproducibility, etc., and targeted distinctions should be made. Even different weaving methods of the same fiber have different requirements for dyes. Dark colors should focus on the amount of color and lifting rate, while medium and light colors should emphasize leveling and hiding properties.
(2) Technical basis of three primary colors:
Three primary colors In color matching, since each primary color dye has a dominant position in hue and light, and the range of changes is large, corresponding technical means must be available. First of all, comprehensive measurement work must be done: mainly accurate measurement of the effective content of the dye (accuracy within 1%), accurate measurement of the difference in dye uptake rate between small samples and large samples. Secondly, the measurement of dyes and chemical materials in large-scale production must be absolutely guaranteed. Modern technical means and strict management measures are required.
(3) Economic advantages of three primary colors:
Three primary colors Compared with color matching with non-primary colors, the latter has a narrower color adaptability, and the variety of dyes in stock must be wider, which makes the total inventory of dye reserves larger and the amount of working capital occupied.
The application of three primary colors has the following advantages.
① It has a wide range of color adaptability and can save most of the secondary color dye varieties.
② The color matching of the three primary colors is basically not affected by changes in popular colors and different color preferences in different regions, because any change in color is inseparable from the three primary colors.
③ Very quick and sensitive to the adjustment of hue and light.
④ Reduce production costs. The inventory of dyes can be reduced. Some tertiary color dyes are blended products, and the selling price will increase after blending.
⑤The technical conditions for color matching of the three primary colors can make the dyeing hue and color light basically stable.
3. Color matching suggestions
(1) Reduce as much as possible The number of dyes used for color matching. The first choice is a single color (including mixed dyes supplied by the dye factory), followed by two mixed colors, and at most three mixed colors. Try not to use four or more dyes for color matching.
(2) The same dye will have different color changes at different color depths. For example, if the dosage of reactive red X-3B is less than 0.5% (o.w.f.), the color will be yellowish; if the dosage exceeds 1% (o.w.f.), the color will gradually become blue. For this change in color light, the maximum absorption wavelength is measured with a spectrophotometer. Generally, there is no change, but the human eye can clearly feel the change in color light. This variation will also vary from fiber batch to batch. In this case, if the hue of the imitation is basically the same, but there are differences in shades, and if it is deepened or lightened in equal proportions according to the formula, the amplitude exceeds 15%, the shade will change. At this time, overall consideration must be taken to make the color and light consistent.
(3) In the tertiary color type, the influence of the three primary colors is: cyan is the most sensitive to brown and brown; yellow is the most sensitive to dark blue and navy. ; The color most sensitive to crab blue and dark green is red. When determining the recipe, be flexible.
(4) For bright colors, the blending of shades requires the use of dyes of the same hue and different shades.
(5) For dyeing with deep colors, the optical illusion caused by subtractive color mixing can be used to reduce the total amount of dye used, which can reduce costs.
(6) For some extremely dark colors, dyes with different structures and the same hue can be mixed to achieve depth.
In addition, the characteristics of dyes should be considered when color matching. For example, reactive dyes, in addition to neutral colors, can consider more three primary color combinations, while disperse dyes can consider using non-three primary color combinations. color, or even black to add depth. </p
