Why Grainlines Are So Important

Grainlines Are The Signposts That Really Shouldn’t Be Ignored.

But What Are Grainlines?

Grainlines feature in both woven and knit fabrics, but are far easier to see in a woven fabric. Woven fabrics are made up of vertical threads (warp threads) that run the length of the fabrics, and horizontal threads (weft threads) that run across the fabric at right angles to the warp threads. 

The warp threads are the foundation of the fabric and hold its strength. Whereas the weft threads are usually more decorative and wiggle their way over and under the warp threads in different formations to create the patterns within the fabric. Both of these threads run in different directions and create the lines in which the grain of the fabric runs – grainlines. 

The warp threads hold the straight grain which is strong and fixed and runs parallel to the selvedge – the neat or finished edge of the fabric that runs either side of its length. 

The weft threads hold the cross grain that can have a bit more ‘give’ to it than the straight grain, but is useful in itself. 

Then to throw another into the mix, there is the bias grain. This is not to be confused with the cross grain as I have heard people call it sometimes, no this is all on its own. The bias runs at 45 degrees to both the straight and cross grains and runs diagonally across the fabric. 

Grainlines On Knit Fabrics

Grainlines are pertinent in knit fabrics too but slightly different to woven grainlines. As a knit fabric is a continuous thread looped around itself, the grain is usually referred to as the ‘direction’, as in the direction of how the loops are created – vertically or most usually horizontally.  If you look at a hand knitted jumper you can see this more clearly. Most knit fabrics are created by knitting rows back and forth or possibly in the round. Sometimes fabrics are knitted along the length but this is not as common, but the loops are called courses if created horizontally or wales if created vertically. 

The ‘direction’ also applies to the greatest amount of stretch in the knit fabrics. This will usually be across the fabric but you can easily check by giving the fabric a gentle stretch in either direction. Quite often knit or stretch patterns will place the grainline in the direction of the greatest stretch. Which can mean the pattern is placed along the cross grain rather than the straight grain. Always double check your pattern information. 

How to check the grain of a woven fabric

It is important before cutting out any pattern pieces that you check the grain of the fabric. Sometimes it can become twisted if the fabric is not rolled straight or if it’s folded and blocked onto a board. So it’s a good idea to check this before cutting as it can have an adverse affect on your sewing if your garment is not cut correctly. 

First of all you can just look at the fabric. As it’s lying on the table does it look straight? Do the cut edges meet the selvedge at right angles? 

If not, fold the fabric so the selvedges meet. If the fabric buckles and twists along the fold, slide the layers of fabric until the selvedges are still together but the fabric lays flat at the fold. Now look at the cut edges. Are they level or staggered? Is it just the cutting that is off or the cross grain? If it’s just the cutting you can trim the ends so everything is neat and along the cross grain correctly. 

But if the cross grain looks off then you need to double check that first. You can do this by gently but firmly pulling a thread across the fabric. It will leave a slight gap in the weave and you can follow this to the selvedge to see if they meet at right angles. 

If the cross grain is still off and the fabric is slightly wonky, you can wash it and while still damp pull the fabric diagonally to straighten the cross grain. You will probably need an obliging friend to help with this. Once pulled out straight you can leave to dry naturally. 

Why Are They Important? 

Grainlines are the signposts we need to tell us the direction we need to place our pattern pieces on to the fabric. 

Remember I mentioned that the warp threads are the foundation of the fabric and the straight grain runs along these threads – well these threads are what the fabric hangs from. Try holding up some fabric across its width and see how it falls. If you hold it so the warp threads are truly vertical the fabric will hang straight and true. But if you are slightly off the vertical then the fabric will fall awkwardly and maybe kink and twist as it falls. 

So to wear clothes that hang straight and true and look balanced, we need to follow the warp threads and the straight grain. A good analogy is to think of hanging wallpaper. You really have to nail the first piece using a true vertical plumbline so it hangs perfectly and all the other pieces will follow suit. If the plumbline is off then none of the pieces will hang properly and it causes a lot of problems. 

You will have noticed on various pattern pieces there’s usually a long line with an arrow at each end. This shows you the direction of the straight grain. Pattern pieces will normally (she says, as there are always exceptions to the rules) need to lay parallel to the selvedge in order to hang straight and true once the garment is made up.

Now as with a lot of things in life, once you know the rules you can bend them to suit your own needs. So although the straight grain is one that we will use the most, we can use the other two grains to create different effects within the garments we want to make. 

Using The Cross Grain

The cross grain can also be used to good effect as it still runs perpendicular to the straight grain, meaning the fabrics will still hang true if the grain is followed. 

So this means we can turn the fabric 90 degrees to make the most of a particular pattern, if for example the fabric has a border print running along its length or we want a stripe to run horizontally instead of vertically. Great in looser styles like gathered skirts or easy fit tops. 

This does have its own challenges though, as the cross grain can have a bit more flexibility in it than the stronger straight grain, meaning the fabrics can stretch slightly along the cross grain. So it can be used, but advisedly. You will need to be confident of the stability of your fabric before using the cross grain in garments that have more structure to them like fitted jackets or trousers. 

Using The Bias Grain

The bias grain lies diagonally across the grid that is created by the warp and weft threads. If you try and pull a fabric along either the straight or cross grain you will find little if any movement in the fabric. But if you try and pull the fabric across the diagonal bias grain you will find much more give in the fabric. 

Try holding up a piece of fabric along the diagonal bias grain. Even the most stable of fabrics will drape and fall more softly. We can use this drape and slight stretch in the fabrics when it is cut on the bias grain to give a wonderful effect in certain garments as the fabric falls over the body it almost fits where it touches. 

This is used to the best effect in lightweight fabrics such as satin crepe, chiffon, or even a modern viscose rayon. Silhouettes and garment shapes need simplicity as most of the fitting comes from the fabrics ability to drape over the curves of the body. 

One of the greatest exponents of this was Madame Vionnet, a french couturier at the beginning of the 20th century. She was one of the first to champion this form of cutting and specialised in creating garments that seemed to just flow over a woman’s body. She was a master geometrican and although her garments appeared simple the cut was highly complex and the finish superb! You can find out more about her in this article by the V&A. 

Creating garments that are cut on the bias will take more fabric as the shapes of the pattern pieces will be naturally curtailed by the width of the fabric. This can mean more panels and pattern pieces are involved. 

How To Use And Check The Grainlines On Patterns

The grainlines that are printed onto the paper pattern pieces will run parallel to the selvedge. So although the pattern piece itself may be an odd or awkward shape the direction of the grainline on the paper pattern piece itself will tell you how to place it onto the fabric. 

To check the pattern piece is following the straight grain you can place the pattern piece on the fabric and just eyeball its position to start with. Then measure from one end of the grainline to the selvedge and note the distance. Measure the other end of the grainline to the selvedge and adjust to both measurements are the same. The grainline on the pattern will now be running parallel to the straight grain on the fabric. 

Hopefully you now love grainlines as much as I do and understand these are the signposts not to be ignored. If you follow the grainline of your fabric and place the pattern pieces accordingly you will be well on the way to making a beautiful well made garment. 


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