Alternating two different visual stimuli induces the perception of flicker. Such stimulation is often used to induce steady state visually evoked potentials in the Neurosciences. If the stimuli are alternated at a higher frequency above their flicker-fusion threshold they are perceived as non-flickering. For example, alternating black and white at a high frequency is perceived gray. Nevertheless, a transition between phases is still perceived (e.g., when switching from sequential presentation of black-white to white-black, the white stimulus is presented twice in direct succession; which creates a noticeable percept). If it were possible to reduce the perceptibility of such phase transitions, we could improve and generalize the stimulation sequences used for steady state visually evoked potentials. In a study with n=24 participants, we will focus on reducing perceptibility of such phase transitions. We will investigate different types of phase transitions in black-white flicker stimuli: (a) gradients between extrema, which uses gradual shifting between black and white for reducing the contrast and embedding a transition at the perceived mid gray level, (b) (high- and bandpass) filtered direct transitions, and (c) flipping pixels in which individual pixels are changed from one phase to the other (e.g., from white to black). We will compare sensitivity of participants to transitions created by those techniques using two-alternative forced choice tasks and thereby identify techniques that are best suited to render phase transitions almost imperceptible.