Launching the Color module

Screenshot of Color module asking to set full mask.
If a full mask is not set, the Color modules allows you to set it now, as colour balancing is typically applied to the full image (requiring a full mask).

Upon launch, the colour module blinks the mask three times in the familiar way. If a full mask is not set, the Color modules allows you to set it now, as colour balancing is typically applied to the full image (requiring a full mask).

An automatically colour balanced M101.
StarTools tends to come up with a reasonable colour balance by default.

In addition to blinking the mask, the Color module also analyses the image and sets the Red Bias Reduce, Green Bias Reduce and Blue Bias Reduce factors to an value which it deems the most appropriate for your image. This behaviour is identical to manually clicking the 'Sample' button.