Pressing Your Patchwork
One of the most pleasurable parts of piecing together a quilt is when you take your block to the iron to press it. It is exciting to see your work pressed flat and how good your block looks.
However, that which is one of the most pleasurable moments in piecing and quilting can also do the most damage.
First of all, fabric is fluid, and pressing can distort your work. In order to avoid distorting the fabric, here is the most fool-proof way to press. Always finger press your work first.
Use your fingers and flatten the seams. Then gently lay the iron over the seams, and just push down. Down not move the iron around. Just press down.
You may want to continue doing it. Again...this leads to trouble. Do not be tempted to press more than one time. If you continue pressing, it will cause the edges of your seams to make ridges on the outside. You will not be able to remove them.
THIS IS WHY IT IS IMPORTANT FOR YOUR FABRIC TO BE PRESSED BEFORE SEAMING. You do not want to make ridges in your block trying to get out wrinkles you could have removed before seaming. The smaller the piece, the more unattractive it will become with additional pressing.
As far as directional pressing, you usually press seams so that the light seams go under the dark ones so they can't be seen. If, however, the seam wants to go another way, you may have to rethink that.
You want to do everything you can so that when seams are joined, one is pressed to the right, and one to the left, to avoid bulk.
Notice how the seams are pressed on the simple and frugal spool quilting block. This is a simple 9 patch block.
Going down the left side of the block, notice how the horizontal seam in the top row if pressed to the right, then in the next row it is pressed to the left. Then it is again pressed toward the right.
The horizontal seams, which were done last, are pressed toward the center so they will lay flatter. If they were pressed to the outside, there would be more bulk from the patchwork seams.