Working with a Half Drop Pattern
When buying curtain fabric, sometimes a fabric will be labelled as having a half drop repeat, half repeat or half drop pattern. What that means is that every other repeat of the pattern widthways is dropped halfway down from the previous one – see this explanation.
A fabric will only be labelled in this way if it means that you cannot match the pattern directly across the fabric. In this photo you can see that when you put the two edges of the fabric together, the pattern does not match.
This means that when measuring for curtains and calculating curtain fabric, you need to allow for this in the calculation. If you use the method shown and work on the set number of pattern repeats for each length of fabric, you will end up with curtains where the pattern does not match. The answer is to move the fabric up half a pattern repeat so that the edges do match as shown in these pictures.
So if your fabric is shown as a half drop repeat, what you will need to do is calculate the fabric as shown and then add one whole pattern repeat to your order. You do not need an extra pattern repeat for each width if you follow the method below. In theory it is possible to add only a half a pattern repeat, but usually a whole pattern repeat is added to allow margin for error and some flexibility about where on the pattern the curtains will start.
In the example on our measuring for curtains page we needed 5.85 metres of fabric in total, working with a pattern repeat of 65cm. If the pattern was a half drop repeat, we would now add a further 65cm to this total to get 6.5 metres needed in total.
You need to be careful when cutting out your fabric to get the best results. No matter how many widths of fabric you need for your curtain or room, you need to give them all a number in sequence. For our example curtains we are working with 3 widths of fabric, so we would number them 1 to 3. Then you would start cutting all of the odd numbered widths, in this case 1 and 3. We would cut 2 lengths of 3 pattern repeats from our fabric with no gap between them.
Then you need to cut off half a pattern repeat from the fabric before cutting the even numbered pieces.
For our example we would cut half of 65cm, which is 32.5cm. This piece will be discarded unless you have another use for it. Then cut out all the even numbered widths, again with no gap in between. In our example this is one piece – width number 2.
So long as you now attach odd numbered widths to even numbered widths, you should find the patterns match from one width to the next. In our example we are making a pair of curtains with one and a half widths of fabric in each so we would now cut width number 2 in half down the length of the fabric and attach half to width 1 and the other half to width 3 making two curtains.
If you are in any doubt about your calculations and are using one of our fabrics, please do ask for our help in calculating your requirements.