
Matthew Williamson is one of my all-time favourite designers. It's his bold use of colours and patterns and his use of animals which draws me to his designs.
Influenced by this, I'm going to show you how to create your own mirrored butterfly and show you a couple of ways to customise it to your own design. If you want to just customise your butterfly, you can download the attached .AI file on the right and get to work.
What You'll Need
In order to complete this tutorial, you'll need to get an image of a butterfly, if you're like me and not so confident freehanding one. You can get many from stock sites, such as PhotoDune. The one I'm using has multiple varieties.
1. How to Set Up a Live Reflection
Step 1
In order to create a mirrored butterfly, you're going to need to create a document which will reflect one side of the butterfly in real time.
First create a Web document which is 1280 x 800 pixels. Using the Line Segment Tool (/), find the centre point (which will show when you enable Smart Guides (Control-U) and mouse over the area).

Then hold Alt-Shift and drag the line from the centre to the edge of the artboard. This will create a perfect vertical line. Then turn this into a Guide (Control-5) and Lock it in place (Control-Alt-;). Lock the layer which contains the guide.

Step 2
Let's define the area where you draw half of a butterfly.
In a New Layer, use the Rectangle Tool (M), which aligns with the guide and then covers the remaining half of the artboard. It's fine if it overlaps the edge of the artboard, as long as it doesn't overlap the guide.
Make sure that this rectangle does not have a stroke applied to it. My screenshots will show otherwise, purely to show you the boundaries of the shape.

Step 3
The layer that contains the rectangle is going to house the butterfly details. We need to apply the Transform Effect to the actual layer rather than an object in order to do this, so click on the button to the right of the layer in the Layers panel to select the entire layer and its contents.
Click on Effects > Distort & Transform > Transform. The settings you want to change are making sure that you're reflecting on the X axis. You want to create 1 Copy, so you want the original showing and a copy of that. You'll see a 9 square grid to the left of the Copies option. Select the left-middle option. Then click on OK. You can check it's applied to the layer by looking in the Appearance panel. It should show Layer, Contents, Transform.

Go ahead and test this out by drawing in the original rectangle you've drawn and see it mirror in real time.
If you're finding this part difficult, you can download the attachment to the tutorial as it is just this mirrored effect so you can join in.

2. How to Start the Line Art
Step 1
To start the line art, I'm first going to File > Place a reference image of a butterfly on my canvas. You can learn how to draw them from scratch, using our step-by-step tutorial on how to draw a butterfly.

Step 2
I would first start by drawing the key shapes to the butterfly using the Pen Tool (P). I've drawn the body, eye, antenna and wings. This is of course automatically mirrored.

Step 3
I then will add the detailing of the cells, following the stock image.

Step 4
Using the Width Tool (Shift-W), I modify the width of the antenna to create a bulb effect at the tip.

Step 5
I use the same process to modify the width of the strokes around the butterfly wing outlines. This helps to clearly define the wings.
Note, it may not be anatomically correct to do it this way, but it is always fun to play with the Width Tool!

3. How to Colour Your Butterfly
Step 1
Another fun tool to play with is the Live Paint Bucket (K). However, I need to expand our line art before we use this so we don't disrupt our Width Tool applied lines.
Hold the layer which contains all of your butterfly shapes and drag it over the New Layer icon in the Layers panel. This will duplicate the layer and its contents. Then go to Object > Expand. You'll notice that you'll find two groups containing the left and right sides of the butterfly. Go in the groups and remove the Rectangles and the shapes for the body as those shapes will remain the same colour for other designs.

Step 2
Delete the left wing as we'll only be using the right. The right wing will later be moved into our live mirror layer and will automatically be mirrored to create our left wing.
Using the Live Paint Bucket (K), fill in the cells of the wings. In this design, I'm using purple.

Step 3
Let's Object > Expand our Live Paint group. Select all your purple shapes and put them in a Group (Control-G) and then select your line art and make a Group of them. Then move the purple shapes down to the original mirror layer.

Step 4
Duplicate the purple group and then fill the shapes with a black to white gradient. Using the Gradient Tool (G), modify the direction and placement of the gradient to show the black is closer to the centre of the butterfly body.
Then set this group to Blending Mode Multiple, Opacity 50%. This helps create a subtle gradient in the cells.

Step 5
Duplicate the group again, and this time turn the shapes into a Compound Path (Control-8). I then apply a blue to white radial gradient to the wings and set the Blending Mode to Color Dodge to create hues of blue, pink and white to the wings.

Step 6
Let's add some darkened tips to the cells. I do this by duplicating the wing compound path. I then use the Pen Tool (P) to create a scalloped edge for the cells.
Using Pathfinder > Intersect, I isolate the overlapping edge from the duplicate of the wing. I fill it with black and reduce its Opacity to 50%.

Step 7
Fill in the body of the butterfly as black and bring the eyes to the top and give them a colour which is similar to that found in the wings. This will give us our finished butterfly.

4. How to Create Different Varieties
Circus Tent Butterfly
None of these butterflies are real, in their colour or names. But it's fun to think of names based on their appearance. This colour scheme reminds me of a circus tent.
I used the same gradients, just with alternating colours of orange and pink. I then used the Blob Brush Tool (Shift-B) to add dots along the edges and corners of the cells. I used the same tool to add further detail to the head of the butterfly.

Bitter Liquorice Butterfly
This one reminds me of lemons and limes, which are bitter in taste, and liquorice because of the black. I've filled in some of the cells with black and the others with green. I applied our scalloped edge to add more black to it. The overall gradient (Color Dodge step) was a green to white gradient which added yellow into the design.
I used the Pen Tool (P) to add additional yellow stripes within the centre of each non-black filled cell.

Awesome Work, You're Done!
I never named our first butterfly. Let's name it the "Amethyst Butterfly" as it reminds me of the colours found in the crystal itself.
We've finished our three designs, so it's time to show me your designs and the name you give it. Upload it to the comments, and let's see how many we can make.
