Always prepare your fabric for sewing or crafting by removing the selvage edge.
The selvage is discarded because it lacks print, but mostly because it will pucker once the fabric has gone through the laundry.
The following method is intended for fabrics that should not be ironed.
This guide is set up for right-handed instructions. You can easily convert to left-handed instructions by flipping the photos upside down.
Unfold your fabric so you can work with a single layer.
Begin by lining up the selvage on your cutting mat.
Don't worry about the bottom side of the fabric, this will be uneven from the store cut and should not be used as a guide. This can be fixed later.
Next; Line up your fabric ruler, with the selvage edge, making sure to cut beyond all of the selvage (the white and the printed portion).
Hint: Line up your ruler with the selvage edge, as well as the lines on your cutting mat.
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Rotary Cutters, like this OLFA brand,
are essential for precise cuts and really save time.
After you have made the cut, with your rotary cutter, carefully peel back the fabric
without moving the ruler,
so you can ensure no portion remains uncut.
If you find some strands have not fully cut,
now is the time
to run your rotary cutter along the ruler again.
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Once you are certain you have a clean cut,
now you can remove the ruler.
It might help to slice-off the hanging selvage,
before you slide the ruler up to continue cutting the remainder of selvage edge.
Continue sliding the ruler up the selvage,
repeat all the steps
until you have come to the end of the selvage.
Turn the fabric over
and repeat on the other selvage.
Now you can use these "selvage-free" sides as your guide to straighten out the other edges, or to line up patterns, etc.