This is going to be a hit! When we saw The Tidal Change, our jaws dropped to the floor. Timothy Paul has somehow cracked the code on the Erdnase Change. This looks gorgeous and...we're going to say it...this is the DEFINITIVE version of this classic sleight.
For all its stiff, mechanical shortcomings, The Erdnase Change remains a PRACTICAL color change because no palming is required. The card is changed without any break or preparation. But, it looks a bit like what you're doing...sliding cards backward and forward.
Timothy's ingenious tweak is to keep the hand PERPENDICULAR to the deck, so that it appears that the face card is partially in view ALL THE TIME. Yet somehow, the card still changes. This is a difficult sleight, but well worth your time.