Street artist HEX shares a step-by-step guide on how to making his stippled, optical illusion pieces
This process will create a stipple portrait onto the surface of the clay. The image is made up of thousands of dots, and ‘pops out’ when light casts a shadow from the raised dots.
I wanted to create a process to put portraits onto clay, as I wanted to make a street art tribute to Bowie. As this an experimental process, I’m sure he would have approved!
Step 1: Select your photo
Your file needs to be quite large-format. This one is 1200×675 and PNG or JPEG format.
Step 2: Get a stipple generator programme
There are lots of stipple generator apps for phones but this one is a free desktop version from Evil Mad Scientist, called Stipple Generator 2 available from the Evil Mad Scientist website
Step 3: Stipple generator settings, and editing the image
The stipple generator website has a great in-depth tutorial, but for this project there are only are three main settings you need to look at.
Once you have launched the app, look for where it says ‘LOAD IMAGE FILE’. Click on that and select your image. Once uploaded, slide the lighter blue part of the STIPPLES box to the left or right to increase or decrease the setting, until it shows around 2,000. It’s hard to get it exact.
Next, do the same for the MIN DOT SIZE field and set it to around 5, and set the DOT SIZE RANGE to 1. This will create a big enough individual dot to cast a shadow, and enough of a range in dot size to add detail to the image.
The image will automatically start to populate with dots that will look a mess at first. Don’t worry; after the programme has optimised the plotting path about 40 times the image will be a lot clearer. This whole process will take about five minutes. However, if you want to use a higher number of dots then this will considerably slow down the time it takes to optimise the image.
You can then save the image (SAVE STIPPLE FILE) as a JPG, open it in your favourite editing software, and crop the image to the desired size.
Step 4: Making the mould
There are two ways to prepare the press-mould. You can either laser-cut, as the image above, or use a hand-held etching tool like a Dremel or a normal drill. This may sound daunting but the hand-held drill can be just as fast.
For both laser cutting and the Dremel method, I have found it’s best to use birch plywood. It requires quite a deep etching on the laser cutter. This has had two runs with a setting of speed 250 and power of 40.
If you are hand-drilling, then print out the image and use some spray mount to attach the image to the wood. Then, using two different drill sizes that are the size of the dots, drill out each dot down to about 3mm.
Step 5: Pressing the clay
Roll out a slab of clay to about 10mm. Make the slab bigger than the picture as you can always trim it back later.
Dust the mould with talc, or spray with a hydrophobic coating (such as waterproof clothing spray), to prevent the clay from sticking.
You need to press the clay into the mould with your fingers or the palm of your hand. Rolling the clay with a rolling pin doesn’t work, as it doesn’t push the clay into the dots. You don’t need to push too hard, but remember to push down and not outwards.
Most clays work well on this; porcelain can be a bit sticky, terracotta gives a nice dark finish. If you don’t have access to a kiln then air-dry clay also works.
Step 6: The reveal
Slowly peel the clay off the mould, taking care not pull it as you go, as you can distort the image. You should then have a reverse image like this.
If you want a true image, then just reverse the image at the etching or drilling stage.
You don’t need any special treatment for the kiln; just fire it as you would any other tile of your chosen clay type.
Step 7: Finishing
Once the tile has been fired you can add thin glaze wash or, as for this tile, a gold gilding wax.
Step 8: Watch it change
To see the effect that tilting has on revealing the image, see here