Image color separation in the most popular screen

At present, many small printing enterprises have the signboard of T-shirt printing, but the system management function of your Xiyi impact testing machine is mainly completed by the administrator to inquire about the basic settings of the system. Most of them only print light colors, not dark colors. Because the same fabric with different colors can't print the same satisfactory effect with the same method. The pattern printed on the dark fabric is obviously dark, which greatly reduces the design effect. Obviously unsatisfactory. To change this phenomenon, the key is not in the printing process, but in the prepress film production. At present, some printing units put a layer of white on dark fabrics, and at the same time, they give up four-color ink and use spot color ink. In this way, the printed fabric effect has been greatly improved. But where did the white film come from, and where did the spot color film come from? We have to work hard on color separation. This article takes Photoshop 7.0 as an example to briefly describe this skill

1. Check and analyze the manuscript

the antibacterial material of the printed manuscript has become a "favorite" in the household appliance industry. After getting it, first check whether its size and resolution can meet the requirements of customers. Secondly, check whether the color model is RGB or CMYK. It is worth noting that although the original requires CMYK format when printing, the RGB original must be provided by the customer before color separation at this time, otherwise a lot of information has been lost in the process of converting to CMYK format. Finally, check the background color of the original. That is, the background color of the original should be the same as the color of the printed fabric. If it is different, it needs to be modified accordingly. In this case, the background color is black

after the inspection, do not be busy with color separation, and analyze the original first. Is it partial to some solid color graphics, or focuses on images with tones? Obviously, this example belongs to the latter. In addition, analyze which colors the manuscript is mainly composed of, which means making several spot color plates and which spot colors to use; After knowing everything, start the next step

2. Make a white base plate

copy the original image (image → copy), convert the copied new file into gray format (image → mode → gray), and invert (image → adjustment → Invert). At the same time, open the curve panel (image → adjustment → curve), and use the mouse to adjust the curve accordingly. Try moving the mouse left and right to observe the effect. The goal is not to lose unnecessary subtle levels. Generally, 1/3 is appropriate

3. Making spot color version

first, use the color selection tool to select a main color of the image, open the color range panel (selection → color range), or first open the color range panel, and then use the color selection tool on the panel to select the main color of the image, adjust the color tolerance, and achieve the best level. The so-called best refers to that the approximate range of the color is included, which requires a lot of experience of staff

after adjustment, click OK, and a selection will appear. Storing the selected area (select → store the selected area) will automatically generate a new channel. After canceling the selection, invert the channel

in the channel panel, select the RGB channel, use the color selection tool to select the main tone you think is the best, and write down its R, G, b values. Then select the newly created channel, click the arrow in the upper right corner of the channel panel, click the channel option in the drop-down menu, and change the R, G, b values of the channel color to the R, G, b values you just wrote down. A spot color version is ready

next, choose the hue next to the previous main color, and use the same method to make the second spot color version

4. Make high gloss version and shadow version

paint separately; Do not select the color of the highlight part and the color of the shadow part of the image, and then make two spot color versions. The method is the same as step 3. At this time, there are four more channels in the observation channel panel except for the three channels R, G and B

5. Screen soft proofing

select the RGB channel and clear the image. And set the channel to the color of the printed fabric (black in this example). Click the arrow in the upper left corner and click new channel in the channel drop-down menu to create a new channel

next, open the file made in step 2, select all and copy. Return to the file channel of this step and paste it. At the same time, set the color of this channel to white, that is, the R, G, b values are 255, 255, 255

at this time, open all channels, that is, make all channels visible, and you can see the simulated printing effect on the screen

of course, this effect may also be unsatisfactory, so you need to re select the spot color, and then re make the spot color version according to the steps. If you are professional enough, you can also use the powerful functions of Photoshop to make subtle adjustments to each channel. The effect will be better

6. Conclusion

the next work is to make color separations according to these channels, and then print. But it should be emphasized that in the whole color separation process, when selecting each spot color, we should consider whether the printing unit can allocate the spot color. Although this color separation technique can solve the problem of dark printing image on dark fabric, if any spot color has obvious deviation, it will affect the final effect. In addition, in the whole process, there are many places to adjust parameters. It all depends on the experience of the staff. Practice makes perfect work

source: master printer

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