What color should the thread on the bobbin be?

a color that complements the thread spool
a darker color than the thread spool
a color that contrasts with the thread spool
the same color as the thread spool

number2?

What does your book say?

If you want to choose the color of the thread on the bobbin, the answer is option number 3: a color that contrasts with the thread spool.

To understand why, it's important to know that the bobbin holds the thread that forms the underside of your stitches when sewing. The thread on the spool is the one you see on the top side of the fabric. By using a bobbin thread that contrasts with the spool thread, it can help create a balanced and aesthetically pleasing effect on your finished project.

For example, if you're using a light-colored thread on the spool, it's advisable to use a darker thread on the bobbin. This ensures that the stitches blend well and maintain a neat appearance, no matter which side of the fabric is visible.

An easy way to achieve contrast is to use a dark color for the bobbin thread when working with light-colored fabric or a light color for the bobbin thread when dealing with dark-colored fabric. By doing so, you can achieve a professional-looking finish, as the contrasting colors will hide any minor imperfections in the tension or stitching.

Remember to adjust the tension on your sewing machine accordingly if you decide to switch to a different color or type of thread on the bobbin to maintain even stitching throughout your project.