The "orange peel" effect on vinyl records is caused by worn molds. Rather than having the proper mirror-like finish, the surface of the record will have a texture that looks like orange peel. This introduces noise into the record, particularly in the lower frequency range. With direct metal mastering (DMM), the master disc is cut on a copper-coated disc, which can also have a minor "orange peel" effect on the disc itself. As this "orange peel" originates in the master rather than being introduced in the pressing stage, there is no ill effect as there is no physical distortion of the groove.
What is an effect of using worn molds when casting records?
The "orange peel" effect