Print output accuracy of pictures

We used to make pictures before printing, will have the resolution of the picture set to 300dpi ~ 350dpi, facing a variety of printing conditions. But in reality, this resolution is not universal, we also need to choose according to the difference between the printing process, ink, paper, in order to most truly reflect the highest print quality.

In this book, I see a section that specifically states that if it is a coated paper such as mirror copper, matt powder, or other similar paper, although there is a strong ink absorption, offset printing is a common problem. Is the problem of ink dot diffusion, if the output accuracy is set to 150lpi or more (1lpi is equal to about 2dpi), which is the resolution of the picture 300dpi, there may be ink dot diffusion, so for this type of paper output accuracy to 120lpi ~ 130lpi is appropriate.

According to my own previous experience, ordinary printed black and white manuscripts are 72 to 150 dpi, and color manuscripts are 100 to 300 dpi. According to the proposal given by the owner of a printing factory, the color manuscript for ordinary offset printing has a resolution of 96 dpi. Above can be printed better prints, high-end printing only need 250dpi (about 125lpi) is completely sufficient, which just coincides with the above described in the old beauty book. From this point of view, it seems that the output precision can be summarized as follows:

1, if you are not familiar with the printing process, using 300dpi (150lpi) is more insurance;

2, if you are familiar with the printing process (that is, understand the offset printing process, paper, ink), according to the different printing process, different printing paper, different ink, use 100dpi ~ 250dpi (about 50lpi ~ 120lpi), in order to save resources;

3, in the two-color printing special beads or three-color printing, according to the proportion of color applications, consider whether to use colored paper, such as black and white printing, you can use white black or black white, so only one Ink.

4. The principle of using color is better than two, two are better than three, and three are better than four;

5, unless the printing process is very familiar with, or can get on-site guidance of the printing technician, try not to use more than four basic colors above the color printing, such as six colors, eight colors and so on.

Source: Print Forum