Pressure is a useful medium for interaction as it can be used in different contexts such as for navigating through depth in 3-D, for time-series visualizations, and in zoomable interfaces. We propose pressure based input as an alternative to repetitive multi-touch interactions, such as expanding/pinching to zoom. While most user interface controls for zooming or scrolling are bidirectional, pressure is primarily a one-way continuous parameter (from zero to positive). Human ability to control pressure from positive to zero is limited but needs to be resolved to make this me-dium accessible to various interactive tasks. We first carry out an experiment to measure the effectiveness of various pressure control functions for controlling pressure in both directions (from zero to positive and positive to zero). Based on this preliminary knowledge, we compare the per-formance of a pressure based zooming system with a multi-touch expand/pinch gesture based zooming system. Our results show that pressure input is an improvement to multi-touch interactions that involve multiple invocations, such as the one presented in this paper.