Now let's summarize and share with you the pitfalls and precautions that BK teacher has stepped on in printing over the years. (The article is quite long, but I hope you can read it patiently.) First, start from the document production before printing:

1、 When creating a new file, we need to set the color mode of the file to CMYK and set 3mm bleeding whether we are creating an album, a sheet or a package.

2、 A4 paper is 210X285mm, A5 paper is 210X140mm and A3 paper is 420X285mm. Do not select the default size of the software. That is the print size, not the print size, please remember!

3、 After making the finished product size (the package is the expanded knife layout), make the corner line immediately.

Corner lines are two 6mm lines, one vertical and one horizontal

The setting in AI is as follows:

In CDR, it is set as follows:

4、 After the bleeding and corner lines are set, the layout center must be set. The size of the layout center is not specified, but the four sides must be more than 3mm away from the cutting position. For packaging, I usually set it to 5mm.

After finishing these basic settings, you can start to design the contents of packaging, leaflets, picture albums and other printed materials
You think that after the above basic settings, the pit will collapse???

Actually Pit Now? Just Start

Pit 1: Color

Printing is actually a process of color reproduction. In the process of reproduction, there will always be deviations, which I call color difference! Due to the difference of each ink type (such as environmental protection ink, UV ink, fast drying ink, etc.), manufacturer and raw materials, the ink of different manufacturers has its own differences. Therefore, it is best to find the manufacturer who printed before when printing. Generally, the ink of normal manufacturers will not be easily replaced.

You may have heard the printer's explanation of color difference, which means that the standard of Chinese printing is ± 10%, so how big is the color difference of ± 10%? Let's make a comparison. If the three primary colors are used as the background color, the color difference is completely acceptable.

But
If two primary colors are mixed together

You will find that the color difference of dark blue is the largest. As long as the red ink is reduced a little, the color will be cooler, and as long as the blue ink is reduced a little, the color will be warmer. This is the most difficult to solve, because each kind of ink, regardless of the brand, actually has a different color deviation. Generally, "cyan (C)" is slightly magenta and blue, "magenta (M)" Generally, it is blue and yellow at the same time, but purple, and only "yellow (Y)" is slightly magenta and slightly orange, so it is difficult to batch print the dark blue on the computer screen.

Is there a color more difficult to print than dark blue?

Of course, it is purple.

When the master printer sees that the background color is pure purple, he will die. This is not a joke, whether it is dark purple.

It's still light purple.

The color deviation is not a little bit, and coffee 。

Do you think this is the most color biased?
No, there is another recognized color that cannot be printed, that is 4-color gray 。

Since there are too many colors that can appear in 4-color gray, teacher BK only shows a few obvious ones for everyone to feel. Let's add other pits of printing color.

A: 4-color black

In fact, this is a clich é. Many designers (especially illustrators) who have just done design will choose black C: 93, M88, Y89, K80 when choosing black:

In many cases, they are directly mixing colors in RGB colors. When they are converted to CMYK, black will become this black, but this color will make the back of your printed matter dirty. Since each color is almost covered with more than 80% of the ink, the next sheet will be printed before the ink dries out in the fast printing, If you cover this sheet, you can print more than 10000 sheets of 157g coated paper per hour at most. In addition, you can print at least 1000 sheets if you don't print more than 100 dozens of sheets. 1000 sheets, according to the size of A4 paper, also have 10KG, let alone you are a print album. If you print 1000 sheets of coated paper, it will be more than 80 KG. If this weight is pressed down, the back will definitely be stained with these dry ink.

If it is a text, the printing factory will help you change the color to C0, M0, Y0, K100. If it is an illustration or a picture, during the printing process, if you find it, you can either modify the document or spray more powder (small color blocks are OK), and then reduce the speed. Another way is to change the machine to UV machine for printing, but the cost is high, and the ink is dark, not as bright as ordinary ink.

In this case, the printed black is K100, but if the black is large enough, the printed black is not black enough, but a little gray. When the area is large, please set it to C30-40, M0, Y0, K100. The printed color is saturated, and the monochrome is added with 30 blue. The printed black is faintly blue in the sun, and the color looks black. Full version black value setting: C40, M20 ，Y20， K100， Printed black is thick and shiny.

Some people may ask how small and how big the black color is. It's hard to grasp this. My personal experience is that K100 is enough for the text, C30, M0, Y0, K100 for the title, C40, M0, Y0, K100 for the larger area, and C40, Y0, K100 for the full version of black, M20 ，Y20， K100。

If you mix colors, I don't know whether the back of the printed color will get dirty. My personal opinion is that you can control the total value of the four colors to about 250. After all, it involves the size of ink and area.

B: About spot colors

Spot color I mentioned in the previous article, and the explanation of spot color in Baidu Encyclopedia is that "spot color means that when printing, the color is not synthesized by printing C, M, Y, K four colors, but printed with a specific ink." In fact, in addition to gold, silver and fluorescent colors, many of these special colors are mixed with C, M, Y, K colors and other inks by the master of the printing factory. Under what circumstances do you need to use spot colors?

1. When making process representation, it is necessary to use spot color to distinguish;
2. Due to the small color gamut of CMYK, not all colors can be displayed;
3. When you want to show high class;
4. When the whole print has only one or two colors.

So, where is the spot color pit?

1. Spot color overprint, because the color of spot color generally uses 100% screen, that is, what color is transferred out of the ink, what color is printed, so the color will not be false. Under normal circumstances, the spot color is printed first, and then four colors are printed. Before the printing factory publishes, in order to prevent inaccurate overprint, they will produce white, so, A stroke of 0.1~0.2mm will be added to the edge of the spot color color block for overprint. This operation is to avoid white edges. Such a fine overprint cannot be seen without looking carefully, but the density of the substrate should be high (I will say in the fourth chapter).

2. Similarly, red is spot color, that is, spot color is overprinted on four colors. The printing factory must communicate well. In this case, four colors are printed first, and then spot color is printed. The effect is different in different order.

3. Designers should also pay attention to file processing. When designing spot colors, please do not add other translucent effects or gradient colors.

I use C100, M100, Y0, K0 color blocks as the background color, and add C100 color blocks to it. Then the background color of the left figure is spot color, the right one is unchanged, or four colors. There is no difference on the computer, but once it is printed, there will be:

Why is this?
After simulating spot color as a printing plate,

You can see that when you make transparency, the transparency of the spot color plate is correspondingly reduced, which makes the spot color printing inconsistent with the computer display.

4. Dark black and metallic spot colors, the effect of adding shadows on them is not obvious. When designing, pay attention to it.

5. It is possible to add an external luminous effect to the spot color, but sometimes the printing factory's output is careless or the document is not obvious. At this time, we must tell the printing that this effect exists, and the printed range is not as large as that seen by your computer. Then you need to open color separation preview in AI, check overprint preview, You can see the final printing effect.

If you are not sure about the printing effect, check the overprint preview.
Note: It can only be turned on in CMYK mode.

C: Color difference of spot color

Yes, spot colors also have color difference. If your quantity is large or the frequency of turning the sheet is high, you can talk with the printing factory and ask him to go to the ink factory to mix the color you want, so that each batch of spot colors will be accurate. If you print thousands of pieces every time, and the next order is only issued half a year, the master of the printing factory will help you to mix the spot color every time you print, In this case, there must be color difference. After all, it is manual adjustment, and it is difficult to adjust accurately. Even if you hold the last print, even if the printer has a scale, he is not sure that he can adjust it. At this time, you can only compromise and try to be similar.

D: Quantitative discrimination

The more you print, the more stable it is. If you print 1000 copies, take the first and the last. The color deviation is not a little bit, but if you print 10000 copies, take one out of every 1000 copies, you will find that the color of thousands of copies is very close

E: Color absorption

The value of drawing picture color in PS is different from that in AI. Even in AI, if you embed a picture or not, the color you draw is different. Therefore, you need a four color color book. There are many choices in a treasure. If you have a real sample, compare the manual with the real sample. If there is no real sample, take the color you have absorbed, find the color in the manual, and then compare your monitor. Although it is not very accurate, it is better than disordering the color.

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Since there are so many color pits, how can we avoid them?

1、 If you can not use these colors that are easy to bias, try not to use them, especially the 4-color gray. Please delete them from your color book.

2、 Purple, coffee, dark blue, orange, and gradually changed red, which are easy to color cast, should not be used as background color in large areas.

3、 It is really necessary to use these colors as the background color, and the customer has high requirements for color, so you can choose to use spot color printing to make these colors easy to bias into spot color. Of course, the printed products will also rise slowly. One more thing, if you make one spot color and the other is four colors, please go to a five color printing machine, If you have made two spot colors, you need to find a 6-color printer, and so on. Five color machine and six color machine are still common. Seven color machine and eight color machine are few.

4、 It is suggested that designers should go to the printing factory to follow the color when they have the opportunity, so that they can understand the printing process. It is actually difficult to understand just by reading the text tutorial. So when following the color, please be modest to the printing master. When the printing master brings the printing manuscript to you, you just need to ask, can you go deeper here? Lighter? Red? A little blue? A little yellow? Don't tell me what to do.

5、 In color matching, we should look at the whole, and not on the sample stand of the printing machine. First, whether the color temperature of the light source is qualified or not is not mentioned. Even if it is qualified, our normal color temperature is different from the color temperature of the sample stand, and the color looks different. So we should take the color matching outside and look at it in a sunny place.