Can rubber tiles vary in colour between production batches and subsequent deliveries?
Yes. Each colour has a specified colour tolerance, so the shade of a production batch may differ slightly from the reference shade. Slight colour variation can therefore occur between batches or deliveries. The shade is influenced by the batch of rubber granules, the quantities of pigment and polyurethane binder used, and the degree of compaction during pressing.
The extent to which these variations are visible depends on the type of granules. In coloured ELT tiles, the black granules are enclosed by a coloured coating of pigmented polyurethane binder. Differences between batches are most noticeable here. Natural black and anthracite ELT tiles are made with clear binder. In an EPDM wear layer, the colour runs through the entire granule. Differences between batches tend to be less apparent in both of these versions.
Newly manufactured tiles have not yet been exposed to sunlight. Coloured ELT tiles darken slightly during the first few weeks, while the freshly cut surface of an EPDM wear layer takes on a slightly warmer shade. The colour of a subsequent delivery therefore moves closer to that of the existing tiles over the first few weeks. Where an area has been in use for years, the difference is more likely to remain visible.
For a consistent overall appearance, the full quantity required, including an allowance for spares, is ordered from a single production batch where possible. Tiles from different pallets are mixed before laying. Colour is assessed under comparable lighting conditions.