Garment toiles are the test version of a garment before a designer makes it in the real fabric.
By first making designs in plainer, cheaper fabrics it gives the designer a chance to test the pattern, the fit, the design lines and the proportions without ruining expensive fabrics, and also means that the design can be viewed in its purest form before print and colour distract from any possible construction issues.
Often the fabric used for toiling is called calico, a cheap and readily available form of cotton which has not been wholly processed. Due to the fact that calico is unbleached, it has an uneven appearance and a creamy colour. It can also be quite an unforgiving fabric which makes you work hard to ensure that your shape and line are correct. It is also easy to make correction markings on so that designers can redraw design lines, and do other fitting changes such as cutting into fabric or pinching small amounts out.
All these alterations are then relayed back onto the pattern so that a new toile of the garment can be cut and tested.
Calico is not always a suitable fabric for toiling all garment types, and you should choose a fabric which represents the weight and handle of your final fabric. For example, if you are creating a dress in a heavy jersey then calico will not give you any indication of how the final fabric will drape, and you are better to use another cheap jersey which will fall in a similar way.
Toiles are also used in haute couture to enable a version of the garment to be individually fitted and tailored to the client’s body. Historically, toiles also represented a way for the couture houses to license out their designs.