In general, these two terms are used interchangeably but there are some cases where they can refer to different methods or depths of marking . For instance, surface etchings which involve removing material from an object’s outermost layers until desired design is achieved while still leaving behind a shallow indentation that may not be very noticeable unless one looks closely enough; on the other hand deep engravings remove more volume so as to produce deeper grooves thereby creating more contrast between adjacent lines hence enhancing visibility even when viewed from afar.