Historical Rules · 5 October 2018
Rule 111.4
Official source text from the 5 October 2018 Rules release
If an effect changes any characteristics of a permanent spell, the effect continues to apply to the permanent when the spell resolves. See rule 400.7. Example: If an effect changes a black creature spell to white, the creature is white when it enters the battlefield and remains white for the duration of the effect changing its color.