“I’m sorry for this busy slide, let me talk you through it.” Never be tempted to use a busy slide by either attempting to explain it or by building it piecemeal or worse seeking forgiveness. A busy slide will distract the audience, worse it will distract the speaker. Consider whether there is any value in the item as a whole, break it into smaller and separate slides or forego it as an image completely. Never instruct the audience to simply ignore a busy slide; they will view this as a challenge. Do not use a busy slide.
There may be information, structure or process within a presentation that is exceptionally complex. Images may explain complexity but they may also hypnotise the audience. One must consider beforehand the value of such a busy slide beyond simply highlighting the complexity. Images are, as the cliche suggests, worth a thousand words but images with multiple levels, subjects or processes contained will remain complex even by illustration and force interpretation by the audience. That interpretation must happen within 3 seconds or the audience will be forced into interpretation. Explanation of this complexity only works if the audience follows the speaker intently. The usual response is to focus on the complexity, blank out the distraction of the human voice and attempt to solve the puzzle. (You tried to find Wally [Waldo] didn’t you?)
Instructing an audience not to look at a busy slide is an exercise in futility. You went back to find him. Don’t display the busy slide. It is possible to explain complexity by construction in sections but as it is not possible to focus on multiple images. This approach will often result in audience members focussing on disparate parts of the visual. The speaker too is often captivated by the complexity of the image and will keep returning to view it. Consider instead the rationale of displaying or discussing the complexity. Identify steps within a process and discuss these separately.
Lastly, try to refrain from construction of busy slides that “illustrate” complex relationships using flow and interlocking shapes. Whilst these may look “pretty” they are seldom accurate representations. This will lead to the audience questioning colours or balance or the nature of interlocking jigsaw pieces or their relative size and not actually engaging with the concept being discussed. Such busy slides seldom make the purpose of the creator and raise more questions than explanation can deliver. If one has to introduce the slide and apologise for it, clearly it shouldn’t be in the piece in the first place.
Busy slides should have no place in a presentation. Offering apology or direction will not minimise the problem. Simplify or exclude busy slides.