I recently learnt about "Stretch Factor" in knit or jersey fabrics. I use the term knit/jersey pretty much interchangeably in this blogpost.
As per the tutorial instructions, I made myself a "gauge" for measuring the stretch factor in fabrics.
And I methodically went about analysing the "stretch factor" of all the jersey fabrics in my stash using this gauge.
One by one, I numbered each fabric, measured how much I have and then I placed two pins 5cm apart on the crosswise grain (doubled-over, perpendicular to the selvage) and stretched the fabric along the gauge. Then I did the same on the lengthwise grain (again doubled over).
The photographs really highlight the "knit" of these fabrics which I don't think I'd ever noticed before.
Stable Knits
I have two "stable knits" in my stash. Stable knits are treated like woven fabrics. They do not require the pattern to be adapted to accommodate for the ease or stretchiness of the fabric.
Grey/black crisscross pattern.
Turquoise-green colour sweater fabric with furry texture on reverse side.
From the most stable to the most stretchy...
Super-Stretch -100
I nicknamed this category "super-stretch-100". Knit fabrics with a stretch factor of 100% in both directions (crosswise and lengthwise) are a category unto themselves! I just have one of these in my stash: white with navy stripes which used to be a t-shirt... and which has suffered slight pink discolouration from a washing machine adventure with something naughty and red.
Knit fabrics like this with 100% stretch in both directions require a 10% pattern reduction; usually the reduction is taken from the side-seams.
Super-stretchy
I have 7 super-stretchy fabrics. Some of the fabrics, however, are equally stretchy in both directions, albeit not quite as stretchy as "super-stretch-100"!
This fabric, a deep tomato red which used to be a dress, has 100% crosswise stretch and 85% lengthwise:
Whereas this light grey fabric has 90% crosswise stretch and only 10% lengthwise:
The light grey fabric is woven in a tube! There is no selvage edges - I'd never seen that before. Actually, "woven" is completely the wrong term... because of course we're dealing with "knits" here. So the fabric was knit in a circle.
I think it's fascinating what a big difference there is in the crosswise stretch of each of these fabrics. The red fabric is definitely a "two-way-super-stretchy" knit whereas the grey fabric is simply a "super-stretchy" knit.
More Two-way Super Stretchy knits
Cerise pink. 87% stretch factor in both directions.
I have made baby hats from this green-with-pink-dots fabric and they have worked out very successfully. I only have 60x60cm left. It has stretch factors of 75% and 85%. Because I have so little left, I couldn't guess which direction was crosswise and lengthwise. The tutorial I was taking recently recommended that stretch fabrics are used with the direction of greatest stretch across the body.
I really like the feel of this fabric. But I don't like the pattern! In general, I'm not good with pattern. I try to introduce more pattern to my life, but invariably I don't like the item! I made a dress from this in my very early days of dressmaking but I never wore it. Was it the pattern? The fabric? The fit? My analysis now shows it has 80% / 50% stretch factor.
More Super-Stretchy (but not two-way)
This off-white fabric has 90% stretch in one direction and 32% in the other.
This is a baby pink colour fabric with gold dots. It's not really a fabric I like but I think it would make a great garment. I bought it a week or two ago at a dressmakers closing down sale, she advertised on facebook that she was clearing her studio. I paid €3 for a metre of this fabric, 128W. It has 90% crosswise stretch and 20% lengthwise.
Stretchy
This is the beautiful Nano Iro printed knit fabric. I only have a teeny amount of it: 81x60cm. It has 65% and 20% stretch factors.
This fabric was bought about two years ago to make a dress for a friend but I haven't had the courage to tackle it. I feel I need to be better at drafting patterns and making blocks that fit etc. She's a very patient friend! The fabric is quite thick so it's appropriate for a winter dress. It's much less stretchy than I thought: 57% crosswise and 18% lengthwise. So only stretchy in one direction really.
I bought this light-brown fabric in Penney's. It was sold as a scarf. It is 90x180cm. Stretch is 60% and 10%.
Moderate Knits
This is my newest fabric! A bright multi colour stretch. This is the fabric that I want to make a t-shirt dress out of; the reason I undertook the tutorial on knit fabrics which has led me to doing this analysis on all the jerseys in my collection!! This fabric has 50% stretch on the crosswise grain and 35% lengthwise. It is therefore a "moderate knit" and would require pattern reduction of 2%.
This is the fabric I used to make my beloved "t-shirt dress". It's a two-way moderate knit: 48% crosswise stretch and 45% lengthwise.
I'm calling this "geometric autumnal". It's actually quite a light fabric and I don't know what to do with it! I bought it a long long time ago when I first wanted to make something with knits. Maybe it needs to be lined? I think that's why I bought the off-white fabric! This geometric autumnal knit fabric has a stretch factor of 47% and 20%. At one stage, I made a scarf from a quarter metre of it, it's 150W but it was awful!! Now, having done this stretch analysis, I know that the off-white fabric would not be suitable as a lining because I think that ideally linings and main fabrics have similar stretch factors. The off-white is coming in at 90/32.
This grey marl is a cut-off from a job I did on a friend's summer dress. I don't have much of it, 30x80cm (x2). It has 35% and 32% stretch factor.
Although the picture looks grey, this is a black fabric. It is slippy and shiny which is probably why it came out greyish or silvery in the picture. Dunno if it could be silk, I bought it in Róisín Cross Silks in Dún Laoghaire. Stretch is the same in both directions: 40%.
This pink/salmon coloured knit is quite light and has stretch factor 35% equal in both directions. I used it to make a Sewaholic Renfrew top. It wasn't really appropriate for that fabric as it was too light and the recovery was quite poor; although the recovery when I tested it just now was coming out fine.
Recovery is when the fabric "bounces" back to it's original shape - in the test I'm doing the pin placed at 5cm which had been stretched would either bounce back to the 5cm mark quickly (="good recovery") or would be slow to unstretch. As a rule of thumb, fabrics with poor recovery should not be used to make clothes - they become saggy quickly.
Job Done!
So am I any wiser?
This has definitely helped me to understand knits a bit better. I'm not sure yet how to put the information into practice but it is good to have the knowledge to hand and to have got "stuck in" with knits in this way.
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