Background areas
In making copies of Roman mosaics after knowledge of The Rules this is the most important area.
If you want to know how good a copy of a Roman mosaic is look at the background. If the proper attention has been paid to this then the work is complete.
Firstly we need to look at the original mosaics. As we can see from the images below the background is made up of off- white tesserae and they're not all the same size. The working size for tesserae (tiles) is 8 - 12mm with all the tesserae being hand cut using a hammer and hardie each piece is very slightly different in size and shape though all those used will fall into the average size.
The lines of tesserae run on the horizontal, generally you could run a straight line through the centre of the row but you wouldn't be able to do that along the top or bottom edge of each row. Here lies the skill, you need to be able set the tesserae allowing for the slight difference in size but keeping all the time to one, single line. If at any point the size of tesserae used are too large or too small then this has an effect not only on that row but also the next row you set.
If you have a row with larger pieces on the left half on the line then the next row below it will get halfway across and will reach an area where you'll either need to set much smaller tesserae to avoid the line sloping downwards or to keep the line straight you finish that line with a small triangle cut and then start the row below which should be straight.
This triangle will create what is known as a point of focus. The one point where the triangle is used will, at some point catch the viewer’s eye. Then, every time they enter the room this point will be the first thing they see.
A common mistake I see made is when the tesserae are set using pieces that get progressively smaller but longer, i.e. shaped like a brick. A brick wall has a very 'flat' look to it and with a Roman mosaic you need to get the impression of depth.
You do need to remember though when looking at the original mosaics are that are many different standards of work. The best ones have the background tesserae all set along the same plane, horizontal to the viewer but you will see numerous examples where there have been a number of people working at the same time and the lines vary. The example below illustrates background tesserae being set both horizontally and vertically.
Unless you are making a piece for piece copy you should work to have all your background tesserae running along the same lines. This is a skill which will only enhance your work.
