As some of you know, I have worked as a technical designer in ready to wear (RTW) fashion over the past 25 years. In RTW we deal with the issue of fabric choice every time a garment is reproduced in a new fabric. If the fit is to stay the same, we have to either find the exact same fabric again, or adjust the pattern for the new fabric. The fit is affected by all aspects of of the fabric from weight, composition and structure. When designing patterns for Wardrobe By Me, I always have a certain fabric and look in mind, but I have no control over what fabric choices my customers use.
When working with pattern design for the DIY market, all control stops at the moment a pattern is released, and YOU pick it up and start making your own decisions. I'm sure you have tried buying an awesome looking pattern, but your own garment ends up ill fitting. If you choose a different fabric, your project may turn out perfect the second time. Sometimes sizing up or down the pattern i all it takes to fix all issues.
Making intelligent fabric choices, will get you a better result faster. Here is a list of some of the things you may want to consider when choosing fabric for your next jersey project.
Weight
How heavy or light weight is the fabric, how thick is the yarn used, how twisted is the yarn?
Why is this important to the fit?
The weight affects how thick or thin the fabric is, and therefore also affects the drape of the fabric. Thin jersey tends to be soft and drapey, as opposed to heavy weight tending to be firmer and less drapey. A thin fabric will cling and show off the body shape underneath, where as a heavy weight fabric will stand away from the body thus hiding the shape underneath.
Composition
What is the fiber content and in which combination? does it have Lycra/elastane, is it a natural fiber (cotton, wool, linen, flax, viscose) or a manmade such as polyester, tencel, modal, ect, ect. The man made fibers are in general very stable, whereas the natural fibers are unstable. This means that the natural fibres will change over time in wash, wear and tear.
Why is this important to the fit?
Each type of fiber ads its own griff or hand feel, and will completely change the look of a garment. Cotton and linen is crisp, viscose drape well and silk or polyester is very slinky. A slinky or drapey fabric will hug the body, and if the composition contains Lycra/elastane, the fabric will be stretchy, and you may want to size down. If your fabric is 100% cotton or wool, you may want to consider sizing up, to get a better more comfortable fit.
Structure
What type surface does the fabric have, is it a single jersey, a ponte, a fleece, a french terry, a rib or a brushed isoli (and many other possible structures).
How does the structure affect the fit?
Rib is generally stretchy and flexible, also the reason why it is used for hem, cuff and neckband. If a rib is used for the main body of the garment, you would need to size down, as the bounciness of the fabric, will weigh it down, and the final result will appear much bigger and saggy, and the neckline and shoulder will be stretched out because the weight of the fabric will pull it down and out.
Using a firm isoli (french terry, sweatshirt material) in 100% cotton, or a cotton poly blend will give a structured garment and the volume of the fabric is much more stable and will carry it self. An Isoli with elastane in the composition will weigh more than one without. Again this will affect the fit. if you increase the weight (use a thicker yarn) the fit is also affected.
Some general recommendations
Finally, I urge you to consider your personal preferences, both in terms of style, but also in how you like your clothes to fit. If you don't like to show off your body, don't choose thin fabrics that cling! If you want to show off, don't choose heavy structured fabric that stands away and adding bulk to a thin frame.
If the design calls for a fabric with Lycra or elastane, don't try to make it without!
It the patterns is designed for a woven, and you want to make it in jersey, either find a jersey without a lot of stretch, but also consider sizing down. A pattern designed for jersey often has negative ease compared to a pattern for woven material.
Go to the fabric store, and get acquainted with different types of fabric. Feel the fabric, roll a couple of yards off the bolt, and get an idea of how the fabric drapes and feels against the skin. Get an idea of what is considered to be lightweight, medium weight and heavyweight. Look at the tags on the fabric roll, and get an idea of how the composition affect the surface of the fabric.
Being informed, will help you make the right fabric choices, not only at the fabric store, but also when buying fabric online.
