CMYK Color Mode is what we use in the printing.
First, we need make sure that the artwork we open in the Adobe Illustrator is working under the CMYK mode. Click File — Document Color Mode — CMYK Color Mode
Second, click Window — Seperations Preview to open the Seperation Preview window.Then check the Overprint Preview checkbox. Here we will know the color number to be printed.
Third, click on the eyeball icon in front of each channel name in the Separations Preview panel to turn off visibility for all separations, then turn on visibility one CMYK channel or spot color at a time. If the artwork has no change when you click on a chanel, it means that color exists. Not otherwise.
Before we discuss the importance and necessity of bleed, let’s first expain what bleed is.
1. What is bleed in printing?
Below is a paiting to be printed. The blue line refers to the cut line. Everything outside the blue line will be trimmed. The bleed line is 3mm away from the cut line on the outside. While the green line is the safe line. Every essential elements of the painting needs be inside the safety zone, in case they are trimmed during the die-cutting.
2. Why is bleed necessary during the pre-printing design?
The inaccurate die-cutting is the root cause of the bleed zone setup. The die-cutting is accurate generally, but not 100% in theory. Without the setup of the bleed zone, a thin white area on the edge may appear on the finished piece.
Now we understand the essence of the bleed. Therefore, when we create an artwork ready for printing, the background image must be extended 3mm(0.125″)away beyond the cutline.If a brochure has the final size 210*297mm, then the artwork should at least has the size 216*303mm.
3. Safety Zone
The safe line is usually 6mm(0.25″) away from the cutline. It is inside the cutline. When the texts go over the safe line, they are risk being cut off during the trimming process.
What is a dieline?
A dieline is a 2-dimensional graphic design of the outline of a packaging box, which shows the box cut line and the fold line. Usually the cut line is represented by the solid line and the fold line by the dotted line in another color.
How to create the dieline?
Adobe Illustrator is widely used in the creating of the box dieline. However, AutoCAD seems much more powerful when the box has a complex design and structure. AutoCAD makes the design more accurate and easy when the complicated flip, rotate, and mirror are involved. Personally, I prefer AutoCAD when I need create a dieline.