What is trapping and How to do it in illustrator

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In this Blog, we are going to learn about Trapping in printing.

Introduction

There are various printing processes available to print on various substrates such as paper, plastic, metal, etc. 

In multicolor printing, There is a chance of misregistration happening while printing due to the movement of machine parts. To minimize the registration issue we need to prepare artwork accordingly at the prepress stage for image carrier generation.

There are some processes done on the artwork to minimize misregistration are Trapping & Pull back with the help of software.

Trapping? 

It may be defined as the technique used at the prepress stage to minimize misregistration during the printing of multicolor using the conventional printing process.

There are two types of trapping techniques: 

1. Spread.
2. Choke.

Spread: 

Extension of the color outside to overlap the adjacent color throughout the boundaries of the element. 

Choke: 

Contraction of the color inside by overlapping the adjacent color throughout the boundaries of the element. 

Now, 

Trapping is done manually by using the Appearance and Attribute panel of Adobe Illustrator.

For spread.

Steps are given below: 

1. Open Appearance panel and Attribute panel from window menu.
2. Select the target element.
3. Go to the Appearance panel.
4. Keep the stroke layer below the fill layer and give the appropriate stroke point size.
5. Stroke color is similar to targeted element color.
6. Open attribute panel check the overprint stroke.
7. To check trapping do separation preview.

* Stroke point size is according to the printing process.

For choke

Steps are given below: 

1. Open Appearance panel and Attribute panel from window menu.
2. Select the target element.
3. Go to the Appearance panel.
4. Duplicate the fill layer select the top layer and do negative offset path from fx option.
5. Select the below fill layer.
6. Open attribute panel check the overprint fill.
7. To check trapping do separation preview. 

* Offset path is according to the printing process.

Hope you get some knowledge from this blog.

Note: I am trying to give you my best. It might be some mistake happen. Please comment if any suggestions.