Grain of the fabric – definition
Grain of the fabric refers to the direction of the yarns in a woven fabric
All fabric will have a direction to its yarns (woven threads). The threads will run lengthwise as well as crosswise in a woven fabric in a parallel fashion, interlocking with each other forming the fabric. Lengthwise yarns are called warp – they form the skeleton of the fabric ; crosswise yarns which lie perpendicular to the selvedges of the fabric are called weft, or filling or woof.
In terms of sewing, a reference to the grain of the fabric indicates how the fabric should be cut so that the lengthwise yarns will be parallel to the length of the body for better fit and drape; ie. The lengthwise grain are cut so that they run vertically on the garment/body, and the crosswise grain runs horizontally across the body.
On fabric, when you say grainline, it refers to the direction of the yarns along the warp thread ie lengthwise yarn. This is the lengthwise grain.
The weft thread is referred to as the crosswise grainline. The crosswise grain is perpendicular to length or warp grain. It has some stretch to it but not as much as bias grain. The crosswise yarn is fuzzier with more slubs than long grain yarns and when folded will not lay flat as length grain, but will be a bit bouncy.
In a sewing pattern grain line refers to the lines marked on the pattern to give you directions on how to place it on the fabric . Generally, it indicates that the fabric should be cut so that the lengthwise yarns are placed along the center front and back, down the center of the arm , down the center front of the pant leg etc. Bias grain and crosswise grain are also used depending on the design.
The ends of the grainlines will have arrowheads to show direction, for your understanding
The sewing pattern is kept on the fabric such that the grain line mark is parallel to the selvage of the fabric. This is how the fabric is cut with the right grainline according to the pattern
So what is bias grain?
Bias grain refers to the diagonal direction of a fabric. This direction has a lot of stretch on the fabric.
When you want a lot of stretch from a woven fabric bias grain is the direction to place the pattern to cut the fabric. You can cut the fabric in a partial bias direction or a true bias direction – with the true bias you get the greatest stretch – it is the most diagonal cut of a fabric. Learn more about bias grain and bias cutting here.
Why is a grainline so important in sewing?
For one, the lengthwise yarns of a fabric are stronger than the crosswise yarns. They fall and drape better when they fall down the body. The lengthwise yarns stretch lesser than the crosswise yarns.
Bias grain stretches more than either of these grains, with the true bias grain having the most stretch. This helps in better fitting according to the shape of the body. So it is important that you know the grain of the fabric before you cut the fabric.
Sometimes it may make sense budget-wise to cut the garment crosswise rather than lengthwise but you should do it knowing fully well that it may slightly stretch, sag at places like armpits and hems and may feel uncomfortable generally. Sometimes you end up with a distorted garment. The horror of it.
A bias grain has a better fit and drape but needs more fabric than either of the other grain directions. So you will need to allocate more money for the project for a bias grain cut garment. If you are thinking of the purse you know which direction to go, or rather cut
One more important point to note is that the lengthwise yarn shrinks more than the crosswise yarn as Kathleen Fasanella notes here.
How are selvages placed in a garment in terms of grain ?
The selvages run parallel to the lengthwise yarns in the fabric( warp yarns). On the fabric bold the selvedges will be finished to prevent unraveling of the fabric edges and is a hard edge which you cut off before using the fabric for sewing. The length of the fabric is measured along the selvage.
So do knit fabric have a grain?
In knit fabric the grain is there but it is different – it is called ‘direction’ in knits. Knit fabric consists of a series of loops. Knowing the grain or direction of the knit fabric is as important as in a woven fabric. In knit the direction refers to the placement of loops in the fabric. They are placed in lengthwise direction (courses) and crosswise direction(wales) with the greatest stretch being in the crosswise loop direction( mostly), with them placed perpendicular to each other just as for woven fabrics. A simple stretch test of the fabric will help you determine the direction of stretch on knits.
How to buy fabric which is on grain or which is grain perfect?
ie. Basically How to know if the fabric is off grain?
It is when you buy fabric that you have to ensure that the fabric is grain perfect, not when you reach home and try to cut the fabric. By then it is probably too late .
Some off grain fabric is impossible to cut properly. Never buy a bolt of fabric if you find that it is off grain, however pretty it is , especially if it is a printed/patterned one and you intend to match the patterns. It will be difficult for you to align it properly.
How to find the grainline in a fabric
On a newly bought fabric you will know the grain line in a glance.You will have to ensure that the fabric is cut straight crosswise.
First and foremost just eyeball the corners of the fabric – if the corners form a right angle the fabric is cut properly
you can look carefully at the lengthwise and crosswise thread and ensure that they are at right angles to each other. If the fabric is off grain they will be intersecting at a slanting or curved manner
One better way is to pull a crosswise thread ( horizontal thread) fully across the fabric . When you do that, you get a small gap – cut through this gap. Now fold the fabric by the center selvedges together ; align and match the selvedges/ selvages perfectly. If you find that the edges you cut do not align perfectly ie they do not match you know you have an off grain fabric at hand. If everything matches, all is perfect. Go ahead and mark the fabric for sewing
A similar method done in a slightly different way is to pull the crosswise thread as described earlier ; cut the fabric by this pulled thread and fold by the center to match the edges – crosswise and lengthwise. If the fabric is off the grain there will be wrinkles in the fabric near the center fold. This is going to be trouble as you sew
When the fabric you have is already cut and has no selvedge to recognize the grain you will have to find the grainline with careful observation and testing. The lengthwise grain yarn will be stronger and crosswise yarn thread is weaker and will snap easily. Another way to try to tear the fabric – when you tear the fabric by the length the fabric will tear easily (because of the weak crosswise thread). If you are tearing the fabric by the width it will be more difficult.
Yet another method is to check the stretch of the fabric. Lengthwise yarn stretches less than the crosswise yarn
Dresses shirts, blouses, skirts are cut with the lengthwise grain of the fabric coming down the body
Shirt collar, ruffles and frills, waistbands should be cut with their length coming along the crosswise grain
A bias tape used for piping, binding etc, is cut on the bias grain.
Can I make the fabric grain perfect, if it is found off grain?
If you already bought the fabric and you find that the raw edges do not match, when tested as previously discussed, you will have to try your best to ensure that the fabric is straightened so that it reaches the grain perfect state.
One simple way is to pull the fabric by the bias direction. Fold the fabric diagonally on the true bias grain. Hold the corner where you find the fabric is off grain – hold there and gently pull to straighten. Pull at 6 inch intervals in the bias direction to straighten everywhere.
If you can find a friend to help both of you can hold the two short ends and pull this way and that way along the diagonal till the fabric is loosened and on grain.If the fabric is slightly wet this manipulation works better.
Another method is to use the steam function in your iron box to straighten the fabric with heat.Press the fabric with hot iron in the direction where you want to move the fabric till you get the desired result.
But not all fabrics can be restored like this. Knit fabric, synthetic fabrics, blended fabrics, woven fabrics with finishing done – these are impossible to recover if off grain. They are heat set in the off grain state and no amount of manipulation will restore it to grain perfection. Avoid buying them.