Pattern grading is the process of turning base size or sample size patterns into additional sizes using a size specification sheet or grading increments. This can be done manually or digitally using computerized pattern cutting software. These increments are referred to as garment grading rules. Each specific clothing market area and level has different grading rules.
Grading is a necessary step that must be taken before approaching sample manufacturers or factories, because they require card sets of your specific patterns and an order of garments to be produced. Grading determines how your garments will fit in all sizes.Having a variety of sizes for each of your garments fills out your minimum garment order cost effectively. Grading will not create shape, but will only increase or decrease size of original shape.
Typically, the first pattern is developed in one size and is graded up or down. This sets it to your size standards.
Methods of Grading
There are three basic methods of pattern grading. These include:
Cut and spread: This is the easiest method, which acts as the basis of the other two methods. To perform this method, you must cut the pattern and spread the pieces by a certain amount to grade up, or overlap the pieces to grade down. The only tools you will need for this method are a pencil, tape, ruler, and scissors.
Pattern shifting: Pattern shifting involves increasing the overall dimensions of a pattern by moving it around at a constant distance. After you move it, you redraw the outline in order to produce the same results as cut-and-spread.
Computer grading: Computer grading is the most recent development in grading technology. It is also the fastest method. Computer grading, however, is expensive and usually only large manufacturers can afford it. Computer grading takes the processes of the two former methods and digitizes them.
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:
- Track Shift System or Two dimensional grading.
- 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:
- Bust to shoulder
- Hip to Waist
- Elbow to wrist
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:
- Close or skin-tight fitting garments
- Loose or semi drape garments.
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.
The objectives of pattern grading is to properly increase or decrease the size of a master pattern, but keep up with shape, fit, balance, style and scale of the apparel. Pattern grading commonly used in apparel industry and fashion design sector