This part is just an additional trick that'll help sharpen the image with this effect. This part is optional.
Click on the thumbnail of the top layer to activate (not its layer mask). Use the Gassian Blur filter (Filter> Blur> Gaussian Blur) and apply a very small blur. Using a larger blur will sharpen the image more but halos may appear if you use a setting too large.

Rollover the image below to see the before and after effect
