Fundamentals of Sewing: Seams

Above are the two most commonly used types of seams in contemporary sewing, closed and open seams and they are essentially sewn in the same way but are named differently depending on how the seam allowance is dealt with.

Every other special seam finish will fit under one of these two broad categories. It is always important to plan the best seam finish before you finish the pattern so that you can ensure that you have left yourself enough space.

Steps 1-4 outline the basic steps of sewing any seam:

Take two pieces of fabric where the seam allowance has been marked with a very small cut into the edge of the fabric.
Place the pieces of fabric with right sides together and so that the edges and small seam allowance notches match up.
Sew the two pieces of fabric together from the notch and parallel to the edge of the fabric. If you have a 1cm seam allowance then your stitching line will be 1cm away from the edge of the fabric. Most sewing machines have measurements marked on the metal plate as a guide, otherwise you can mark it on a piece of tape and stick it to the metal place, measuring from the needle to get your guide line.
Unfold the two pieces away from each other so that the right side of the fabric is faced down and the stitching line runs down the centre. From this point you can go either way with your seam finish, you can either have it closed or open.
CLOSED SEAM: Press the seam allowance to one side.
OPEN SEAM: Press down the centre of the seam allowance so that the seam allowance goes equally to either side.

As discussed in the post on seam allowances in pattern making», seams are basically the lines where two pieces of fabric are joined by stitching. When used in the colour blocking trend it is good to know how the perfect seam lines are achieved so that the different blocks of fabric are able appear to be part of one continuous piece of fabric.

For many of the designers who have been using colour blocking recently they would be joining the different coloured panels together with open seams, allowing the fabric to sit flush and meaning that there is not too much bulk on one side of the seam. In some cases when you are looking at the collections you may come across panels with topstitching on only one side of the seamline. If this is the case then the seam has probably been pressed closed and then topstitched to make the seam allowance sit nice and flat to one side.