Why is Bleed so Important?

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.


Creating a Dieline

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.



Difference Between Spot Color and CMYK Color

1. What is spot color?

In offset printing, a color that is produced by a ready-mixed ink is called spot color. There are several spot color system created. The Pantone Matching System(PMS) created by the Pantone Inc. is the most dominant and most widely used.

2. What is process color?

Process color is also refered to as CMYK color, four color. To have a better understanding of the process color, the term of CMYK color model and halftone needs be explained first.

2.1 CMYK Color Model

In contrast to the RGB color model, CMYK color model is a subtractive color model, used in the color printing. CMYK refers to the inks cyan, magenta, yellow and key(black).


The overprinting of the CMYK color can reproduces other colors. Cyan and yellow produce green, cyan and magenta produce a purplish blue, yellow and magenta produce red.

2.2 Halftone

When we create dots small enough and dense enough on a paper, and see them far away enough, the dots blend together into continuous tone. The is our optical illusion. Therefore, halftone is a technique, using half tone dots to create the continuous tone imagery.

Left: halftone dot pattern with increasing size downwards, Right: how the human eye would see this, when viewed from a sufficient distance.

Left: halftone dot pattern with increasing size downwards, Right: how the human eye would see this, when viewed from a sufficient distance

With CMYK printing,  halftoning (also called screening) allows for less than full saturation of the primary colors; tiny dots of each primary color are printed in a pattern small enough that human beings perceive a solid color. Magenta printed with a 20% halftone, for example, produces a pink color, because the eye perceives the tiny magenta dots on the large white paper as lighter and less saturated than the color of pure magenta ink.

Without halftoning, the three primary process colors could be printed only as solid blocks of color, and therefore could produce only seven colors: the three primaries themselves, plus three secondary colors produced by layering two of the primaries: cyan and yellow produce green, cyan and magenta produce a purplish blue, yellow and magenta produce red (these subtractive secondary colors correspond roughly to the additive primary colors) plus layering all three of them resulting in black. With halftoning, a full continuous range of colors can be produced.

As for now, you may have known what process color is. If no, check the animation below.

3.How to tell if a color is spot color or process color?

A 15x magnifying glass, or much powerful, is perfect to tell the difference between a spot color and a process color.