These technical files have been designed to help you make pieces that reach top-of-the-range quality. They explain the working method to follow step by step and each stage is illustrated by precise written instructions and detailed sketches. This particular technical file demonstrates how to make a Bertha collar in the predefined size of your choice and using the neckline of the classical blouse base pattern (or any other neckline). The Bertha collar is characterized by its godets or undulating movements in the fabric that vary in effect depending on how they are formed at the neckline base. Using this base, other transformations are possible. It is possible to work this file in association with the following: The technical file of the classical blouse base pattern The technical file of the blouse sleeve base pattern The technical file of the simplified blouse sleeve.