Random Seed controls random behaviour of the filter. If the same random seed in the same situation is used, the filter produces exactly the same results. A different random seed produces different results. Random seed can be entered manually or generated randomly by pressing New Seed button.

When the Randomize option is checked, random seed cannot be entered manually, but is randomly generated each time the filter is run. If it is not checked, the filter remembers the last random seed used.

If you check this, you'll get very interesting effects, often something that looks much like oil on water, or clouds of smoke, or living tissue, or a Rorschach blot.

This controls the amount of detail in the noise texture. Higher values give a higher level of detail, and the noise seems to be made of spray or small particles, which makes it feel hard. A low value makes it more soft and cloudy.

If you check Tileable, you'll get a noise which can be used as tiles. For example, you can use it as a background in an HTML page, and the tile edges will be joined seamlessly.

These control the size and proportion of the noise shapes in X (horizontal) and Y (vertical) directions (range 0.1 to 16.0).