Thread count analysis

Thread count analysis involves measuring the density of threads used to weave a canvas.

A conservator will count the number of threads going horizontally and the number of threads going vertically (known as the warp and the weft). Once you have this information, you can then compare the thread count to a known work by the artist painted on canvas at a similar time. If they are the same, this would indicate that they are from the same type of canvas, possibly even from the same manufacturer or even the same roll. This is the kind of detail a forger would struggle to imitate.

If the canvas is unlined, it might be possible to count the threads directly from the canvas using a magnifying glass. In other cases an X-ray is used to enable the conservator to see the canvas weave.

Further tests, such as microscopy on the individual fibres and testing of the primer (i.e. base layer) on the canvas, can provide further evidence they came from the same source.