# Threshold Wallust automatically uses the **best threshold**, heuristically, if this variable isn't defined (default behaviour). > If you really want to define this variable, keep in mind the > following. Thershold is the **difference between similar colors** , > used inside the colorspace. > > **Each colorspace may have different results** > with different thresholds, meaning _you should try which one works for you best_. An **overall** table looks like this: | Number | Description | |--------|-------------| 1 | Not Perceptible by human eyes. 1 - 2 | Perceptible through close observation. 2 - 10 | Perceptible at a glance. 11 - 49 | Colors are more similar than opposite. 100 | Colors are exact opposite.