There are differences between macro-ATR and micro-ATR. In macro analysis there is much more variation and flexibility. Microscopically the crystals are much smaller and only provide a one point analysis. Due to the smaller sampling size, the intensity of the interaction tends to be smaller making it more susceptible to noise. Due to the small surface area being analyzed, the amount of pressure being applied to the sample needs to be monitored closely so as not to damage the crystal.