Summary: These are the four masks we used. Only need to SAVE the last two.
PWP workflows will crash if the masks applied are not saved to disk and referenced there.
The first mask is the clean text where the shadow will be. The second mask is the
blurred and brightened unobscured shadow. The third mask is the obscured shadow,
created by the composite transform in subtract mode. The fourth mask is the up and
left-shifted text that will be the base text.