Grading in the apparel manufacturing industry is well known as the art of proportionally increasing or decreasing a given size pattern part from one size to another, retaining everything true to its original form. The grading network for a block pattern is also the basic network for the components which have been developed from the block pattern.
There are many techniques involved in the grading of garment pattern but they all have one common principle- the basic grade. Grading system can be classified in to the following two broad systems:
1. Track Shift System or Two dimensional grading.
2. Draft Grade System or Three dimensional grading.
Two dimensional grading systems only grades a pattern for girth and height and its application is therefore limited to loose or semi drape garments because it retains the stock size suppression throughout the size range. This system is more apt to a very loose fitting garment such as a shirt or blouse with a limited range to say, 10-12-14, may be safely graded using a two dimensional system.
Three dimensional system:
This system not only increases a pattern for size but it also increases or decreases suppression in the following areas:
Three dimensional grading is the optimum system and should be used whenever possible, particularly when grading close fitting or skin-tight garments and garments that progress in size from 10 to 22. The most important garment area is the bust to shoulder suppression quantity. A good working knowledge of pattern cutting is required to use a three-dimensional grading system.
Types of Garment: There are two main categories, they are:
The closer the garment fit, the more important it is to select a sophisticated garment grading system which adjusts the garment with the garment suppression. If the garment fit is loose the value of adjusting the garment suppression decreases and a two dimensional system becomes more advisable.
Number of sizes: This may depend a little on whether a garment is close or loose-fitting, but it mainly refers to a situation where the company or firm only offers a limited number of sizes, the complexity of the grading system, etc.