At a recent conference I realized the impact that ambient light can have on how the audience views your slides. It was a small conference, about 50-60 people in all and the room had two sides with windows. At the start of the day, it was bright outside and the room was bright because of the light coming in from the windows. The white background of the speaker's slides wasn't distracting. Well, during the day, it started to rain and the ambient light coming into the room decreased dramatically. The room lighting wasn't turned up, so what happened is that the white background slides appeared even brighter and drew the focus away from the speaker. It is natural for us to focus on the brightest object in the room and in this case it was the slides on the screen. Because the rest of the room was quite dark, the speaker got almost lost in the background. In "Guide to PowerPoint
", we suggest that using a white background is not a good idea for just this reason. I prefer a dark background because it has worked better for me in the varied lighting situations I find myself in when presenting. Consider this the next time you select colors for your slides.