StarTools stores the masks you used in your workflow in the StarTools.log file itself. This StarTools.log file is located in the same folder as the executables. The masks are encoded as BASE64 PNG images. To convert the BASE64 text into loadable PNG images, you can use any online (or offline) BASE64 converter tool.
The part to copy and paste, typically starts with;
One online tool for BASE64 is Motobit Software's BASE64 encoder/decoder.
To use it to convert StarTools masks back into importable PNG files;
This should result in a download of the mask as a PNG file which can be imported into the StarTools mask editor, as welll as other applications.
This time set 'Old Mask' to 'Add New To Old' to add the newly generated mask to the mask we already have.
The Color module is very powerful - offering capabilities surpassing most other software - yet it is simple to use.
You are forgiven if, at first glance, you get the impression StarTools offers only the basics.
You can convert everything you see to a format you find convenient. Give it a try!