ADJUSTED CUT DROP
When cutting and joining PLAIN fabric drops, you cut the drops to the length of the fabric cut drop, align and join. It is not as simple with PATTERNED fabric.
With a patterned fabric we adjust (increase) the FABRIC CUT DROP so the pattern starts and finishes at the same position on the fabric. The cut drops are then identical* when cut from the roll and the pattern aligns when drops are placed alongside each other for joining. This is called an ADJUSTED CUT DROP.
ADJUSTED CUT DROP - DEFINITION
An Adjusted Cut Drop is the Fabric Cut Drop length rounded up to a whole number of pattern repeats. So the cut drop is now a whole number of pattern repeats.
WHAT IS A PATTERN REPEAT?
We are talking about the vertical pattern repeat here not the horizontal pattern repeat. The vertical pattern repeat is the distance measured down the fabric before the pattern repeats itself. It is usually stated by the fabric supplier. You can also measure it on the fabric.
*DIFFERENT TYPES OF PATTERNED FABRIC
There are generally 2 types of patterned fabric. Standard pattern repeat and half drop pattern repeat (very rarely you may find a third drop pattern repeat fabric). To explain Adjusted Cut Drops we are dealing with the most common type of patterned fabric, which is standard pattern repeat fabric. That is a patterned fabric where if you were to cut 2 identical pieces of fabric and lay them side by side, the pattern would match at the join. With a half drop pattern repeat fabric one piece would need to be shifted half a pattern repeat down for the pattern to match at the join. You will find more information on how to deal with half drop pattern repeats HERE
DO I NEED MORE FABRIC WHEN USING A PATTERNED FABRIC?
Usually yes you do. As explained above you need to increase the Fabric cut drop to a whole number of pattern repeats. Which generally increases the length of the cut drops, increasing the amount of fabric required compared to plain fabric. We usually add a pattern repeat into the total qty to place the pattern as well.VIDEO
HOW TO CALCULATE ADJUSTED CUT DROPS
To calculate the Adjusted Cut Drop:
- Divide the Fabric Cut Drop by the vertical Pattern Repeat
- Round the result up to the nearest whole number (NPR)
- Multiply the whole number by the vertical Pattern Repeat
- You now have the Adjusted Cut Drop as a distance (ACD) and a number of pattern repeats (NPR)
First thing you need to do is find out what the vertical pattern repeat is and there are several ways to do this.
- Check with the fabric supplier when you buy the fabric.
- Along the selvedge edge of the fabric, it normally says who the fabric is made by and the design. Google it along with pattern repeat. This is probably the most accurate way and I always check manufacturers quoted pattern repeat as well as measuring myself.
- Measuring yourself. Look at the pattern and you will see how it repeats down the length. Find a point on the fabric that is remarkable and look down to see where the same remarkable feature is next seen. Measure between these 2 points and this is your Pattern Repeat (PR).
Now work out the FABRIC CUT DROP required as if you were using PLAIN fabric.
This is the point where we need to factor in the pattern repeat by rounding the FABRIC CUT DROP up to a whole number of pattern repeats to create the ADJUSTED CUT DROP. For this example we will use a Pattern Repeat (PR) of 32 cm
Our calculation shows the plain fabric cut drop is 7.65 pattern repeats long, as explained we cannot cut in the middle of a pattern repeat so we have to adjust the drop (round it up the next full pattern repeat). The adjusted cut drop is 8 PR (=256cm)
IMPORTANT - BEFORE CUTTING OR MARKING FABRIC, ENSURE YOU HAVE CHECKED IT FOR FAULTS, CHECKED THE PATTERN REPEAT IS AS QUOTED ( SEE BELOW ) AND THAT YOU HAVE THE CORRECT AMOUNT OF FABRIC FOR YOUR PROJECT.
I ALWAYS CHECK MY FABRIC IN ADJUSTED CUT DROPS. THIS WAY I AM CHECKING FOR FAULTS AND THAT I HAVE ENOUGH FABRIC AT THE SAME TIME. SUPPLIERS WILL NOT RECTIFY FABRIC ISSUES ONCE CUTS HAVE BEEN MADE.
Cutting patterned fabric can be easier than plain as you can use the pattern as a guide. This is how you cut your patterned fabric..
1. CHECK THE PATTERN REPEAT
Firstly, and MOST IMPORTANTLY, measure and check your actual pattern repeat. You will have used the suppliers/manufacturers figure for pattern repeat when ordering and calculating your fabric QTY. However you still need to double check now and measure the repeat on the fabric as they can be out by a cm or 2 which will affect your ACD and possibly the number of pattern repeats required.
See worked examples below for when the pattern repeat is not as stated.
2. PLACE YOUR FIRST DROP ON THE PATTERN
CURTAINS: When making curtains with patterned fabric, you will decide where you want the bottom of your curtain to be as your eye will notice the pattern more at the bottom of the curtain than at the pleated top. So you need to decide where you want the bottom of the curtain to be on your patterned fabric. I recommend looking for an obvious end/break in the pattern. With random patterns, it will not matter quite as much. If you have used our method, you will have 1 spare pattern repeat for placing the pattern.
Once you have decided where you want the bottom of the curtain to be ( not the bottom of your ACD ) pop a pin in the selvedge at right angles to the side . Now measure DOWN THE PATTERN 20cm for the hem and pop another pin in. This is the bottom of your first cut drop(IN THE WORKROOM I USE MY VANISHING PEN MARKER AND WRITE EACH CUT DROP ON THE SELVEDGE AS I GO, RATHER THAN USE PINS). Now measure up the minimum fabric needed (MFN) and pop another pin in here at the selvedge edge. You will not need to trim down the top but it may mean that your first cut drop is slightly longer or shorter than your ACD.
BLINDS: On a wide blind with joins, you decide where you want the top of the blind to be on the pattern. Then measure down blind length + hem allowance to find the bottom of the first cut drop. See our wide blind tutorial for more details.
3. MARK THE OTHER DROPS
- You have now marked your first cut drop and all subsequent cut drops will be the ADJUSTED CUT DROP. I will not make any cuts in the fabric until they have all been measured and marked.
- Roll the first cut drop onto a cardboard roller until you have reached the bottom pip (pen mark). Note exactly where this falls on the pattern.
- Measure down your ADJUSTED CUT DROP from this mark/pin and this should fall in exactly the same position in the pattern as the bottom of your first marked panel. This is crucial as it means that all the panels will line up perfectly once joined together. When marking Adjusted cut drops, I not only measure down but I also count the number of pattern repeats too as a double check. For example, you have measured down 256cm so I also count down 8 pattern repeats.
- Pop a pin/mark at this point where you have marked your second cut drop. (the pin/mark must be at the same point on the pattern)
- Continue in this same way until you have marked all your cut drops.
- Once you have marked all the ADJUSTED CUT DROPS, checked for faults and that you have enough fabric, rewind the role back to the beginning and now you can cut the lengths.
So, this has happened to me a few times and can be a nightmare to deal with so we’ll look at a couple of examples to demonstrate, keeping the Fabric cut drop at (245cm) and stated Fabric Pattern repeat (32cm) as used above.
Manufacturer has stated PR of 32 cm. On checking you see that the actual pattern repeat on the fabric is 31.5 cm. If you cut all your ACD’s at 256cm, they will be wrong as this is not the actual pattern repeat and you will again end up with uneven, staggered lengths when joined together so you need to recalculate the ACD with new PR and check you have enough fabric.
This still works as your ACD is still 8 full PR’s but is now 252cm rather than 256cm. Which means you will still have enough fabric and the ACD is still longer than the minimum fabric required (FABRIC CUT DROP = 245cm).
Manufacturer has stated PR of 32 cm. On checking you see that the actual pattern repeat on the fabric is 30 cm.
According to the method, you should round this up to 9 x PR’s giving you an ACD of 270cm.
This is absolutely fine if you have enough fabric but you may not have as this was not what you made your initial calculations on. So you have a couple of options…
- Get back in touch with the supplier ( providing the fabric has not been cut or permanently marked ), and ask for a new piece to be sent. Alternatively, they may just send you a new piece for the last Adjusted cut drop from the same batch.
- If the difference is not too great, by a cm or 2, you could reduce the hem. For example a double 8cm fold in a lined curtain (I would then reduce the lining fold too to double 6cm so that they line up). For interlined, I would make the first hem fold less but the second still the full 10 cm (keeping the lining as normal because it will the hem will still be 10cm deep).
In this example we would need to reduce the fabric cut drop from 245cm to 240cm, losing 5cm from the hem. (just doable)