“What advice do you have for designers building digital content for transparent displays?”
I know I sound like a broken record, but all design must consider the nature of the project first. If we are looking at transparent content for a mirror or refrigerator environment, the rules are generally the same as other forms of digital signage. You have to remember the very important point that your content is superimposed on something else, either an item people are interested in or looking for, OR their own reflection when trying on an item.
Transparent LED, however, is somewhat different. With larger, more pixelated displays, one has to design with many considerations. What are you trying to achieve? Ultimately, this can only be determined when you take the audience into consideration to give it some context.
Who is the audience?
What are they doing?
Is this an event?
Is this a concert?
Is this a public space?
Does this content need to support some other form of content e.g., live performance, unveiling, music?
Next is Timing and Environment? When will people see this? Day? Night? Light? Dark?
Let’s also consider Viewing Distance. From what proximity will the content be viewed? I’ve seen many semi-transparent LED screens forced into areas where the people passing by are too close to appreciate the content. Conversely, I have seen content that has been designed with far too much detail that deteriorates on semi-transparent LED.
The main message is that you need to design new content for a transparent deployment. You cannot force regular digital signage content into that unique environment.