About our tests

We measured out the recommended amount of detergent for a normally soiled load – or for a lightly soiled load if there was no “normally soiled” recommendation. We then used it to wash soiled swatches that we attached to laundry items. Our wash was done in cold water (20°C).

The swatches we use to measure general washing performance are stained with nut oil, milk and a colour pigment.

Other swatches are stained with grass (to test the detergents’ enzyme action and general stain removal) and tomato (to test enzyme action and bleaching effect).

We used a spectrophotometer to measure the amount of light reflected from the swatches before and after washing. This told us how much dirt was removed. Any effects from optical brighteners were filtered out by the spectrophotometer.