8 Color Tips for Printing?

Under the same lighting conditions, we can see different parts of the same scenery with different colors. This is because the surface of an object has different abilities to absorb and reflect light. Different reflected light will cause the eyes to see different colors. Therefore, the occurrence of color is the result of the effect of light on human vision and brain, and is a perception of human organs. So, how to ensure the color of the printing effect? Below are 8 color tips for printing.

Color consistency

An important method to ensure color consistency is to have customers observe color and printed samples under standard lighting conditions and obtain their approval. In order to reduce the variation of colors during transmission and replication, the printing industry has specially established standard color observation conditions, namely the standard color observation pool (a light source control area with a stable environment set up for observing samples or other printed materials).

This color observation pool has two key elements: first, lighting (color temperature of 5000K); The second is a neutral gray environment (MunsellN8).

It is very important to check the color on the observation pool, as the lighting conditions and surrounding environment when we check the color can affect our perception of the color. If there is no standard observation pool, we can also view the sample in non direct sunlight.

The impact of lighting

When we observe colors under different lighting conditions, the effect we see is also different. Another issue we need to pay attention to when observing colors is homochromatic aberration. The so-called "homochromatic heterochromatic spectrum" refers to the situation where two samples present the same color under a certain light source, but different colors under another light source.

It is very important to maintain stable and consistent lighting conditions when observing colors. The reason why we choose a light source with a color temperature of 5000K is mainly because this light source is a mixture of red, green, and blue light, which can provide people with a stable and consistent observation environment.

Environmental impact

Will the surrounding environment when we observe printing samples affect the color? Adjacent colors, which are colors similar to the observed sample or print, can affect people‘s perception of colors. This is the so-called "critical effect", which to some extent reflects the importance of using a neutral environment when observing samples. It is understood that using standard gray paint (MunsellN8) in the surrounding environment can effectively reduce the influence of adjacent colors on people when confirming colors.

Paper

Subtraction method refers to the method of mixing yellow, magenta, cyan, and black inks in a white environment (usually paper) to form a color. In this color copying process, there is an element that will have a significant impact on the printing effect of the color on the machine, which is the paper.

The same ink color may produce different printing effects on different papers. The whiter the paper, the larger the color gamut that can be replicated on a printing press. If the Baidu of the paper is not enough, then the color gamut it replicates on the printing machine will be relatively small.

Spot color

Each spot color corresponds to a special ink (except for yellow, magenta, cyan, and black) that needs to be printed through a separate printing unit on the printing machine. There are many reasons why people use spot colors in printed materials, and highlighting a company‘s brand image (such as Coca Cola‘s red or Ford‘s blue) is one of them. Therefore, accurately replicating a spot color is crucial for both customers and printing factories.

Another reason may be the use of metal ink. Metal ink usually contains some metal particles and can give printed materials a metallic luster. In addition, when the color requirements of the original design exceed the color gamut range that can be achieved by yellow, magenta, and black, we can also use spot colors to supplement them.

Color conversion

When we convert the color of an image from RGB to CMYK, we usually generate halftone dots of black ink through two methods: background color removal (UCR) and gray component replacement (GCR). The choice of method mainly depends on the amount of yellow, magenta, cyan, and black ink to be printed in the image.

"Base color removal" refers to the removal of a portion of the neutral gray base color from the three primary colors of yellow, magenta, and cyan, which is a nearly black base color formed by the superposition of the three primary colors of yellow, magenta, and cyan, and is replaced by black ink. The removal of background color mainly affects the shaded areas of the image, rather than the colored areas. When the image is processed by removing the background color, it is easy to experience color deviation during the printing process.

The replacement of gray components is similar to the removal of background color, both of which use black ink to replace the gray formed by color ink overprinting. However, the difference is that gray component replacement refers to the use of black to replace all gray components within the entire tone range. Therefore, when replacing the gray component, the amount of ink on the black plate is very small, mainly printed with color ink. When using the maximum replacement amount, the amount of ink on the black plate is the highest, and the amount of ink on the color plate is correspondingly reduced by a lot. The image processed by the gray component substitution method is more stable during the printing process, but its effectiveness largely depends on the printing machine operator‘s ability to adjust colors.

Professional terminology

We find color difficult to describe mainly because it is a sensation, just like smell, taste, and hearing, which cannot be described in words. When we have to use words to describe colors, we often use vague words such as "plain", "cloudy", "too warm", or "too cold".

For example, what is an image that is too warm? Does it mean its color leans towards red, yellow, or magenta? What does "too cold" mean? Is the color of the image too blue, too green, or too green? When we say an image is too "plain", it usually means that its contrast is not enough, while the awareness of "turbidity" means that the color tone of the image is too dark. Using non-standard terminology can prolong the sampling cycle, thereby delaying the production progress of live parts. Therefore, we must use professional terminology when discussing colors - this can save you a lot of time and money.

Printing

Printing is not a "perfect match" process. What is replication? Copying is not a perfect match, but an infinite proximity. Printing is not a completely matching process, mainly because there are many color reproduction systems involved in the color reproduction process. Photography is a typical color reproduction system, as is sampling and printing.