Direct and Indirect Tile Laying Methods
There are many different tile laying methods mosaic artists can use when creating a project: direct, indirect, double reverse, double direct, modified double reverse and probably more. For this overview, I will mention the 2 most common ones: direct and indirect. The direct method is what I recommend all beginners start with and is what I use most of the time for my mosaics.
The Direct Method:
Using the direct method means adhering your tesserae (tiles, glass, etc.) directly onto the base (or substrate) you are mosaicing to. I enjoy working this way because you can see the design taking shape right away and can correct where needed. If you create a 3-D mosaic, you will use the direct method. Here is my grandson using the direct method on a sun Skeewbacker.
The Indirect Method:
The indirect method is also sometimes referred to as the reverse method, and is a little more complicated than the direct method.
This is a project done by Jennie Grover - an art project for Schools in London. I am sharing this as it is a great example of how to do an indirect method. Her website is: https://jenniegrover.com/
For the indirect method, you will start with a pattern that is drawn in reverse. You will temporarily place your pieces, face down (or upside down), to a surface such as heavy brown paper that has been coated with a glue that is water soluble. You will be basically working with a mirror image.
After you finish placing your tiles and it is dry, the entire mosaic can be flipped over and the back side of the tiles put into a bed of thinset or mortar.
After the mortar dries, the paper is then soaked away from the top of the tiles and you will see your design. You can then clean and grout as needed.
The main reason for using the indirect method is if you have varying depths of tesserae, the larger more uneven pieces will bury down into the adhesive, leaving a smooth top surface. This is important for floor mosaics and tabletops where you need your surface perfectly smooth.