Auto-convert Wordpress custom fields into tags?

I just wanted to ask: is there a way to convert a specific custom field’s values into tags?

(custom field) Colors: Blue, Red, Yellow

…and when the page is published, Blue, Red, Yellow are already added as part of the list of tags in the database? (so, needless to say, they show up on that post’s tag list)

Hopefully someone could point me in the right direction?