Transmute Artifact and Colored Artifacts

[Zalren]

What if I cast Transmute Artifact, sacrificing Myr Enforcer, and putting Sphinx of the Steel Wind into play.

How much mana do I have to pay to put Sphinx of the Steel Wind into play? Is it colorless or colored mana?

[keys]

It only looks at converted mana cost. You pay the difference (X) in colorless mana. In this scenario you would have to pay 1.

[Zalren]

Thanks! I was just confused because colored artifacts is something newer than the wording on Transmute Artifact. Many thanks again!