I was thinking about white adhesive plastic wrap/foil
it you only project on it and not the surroundings, you just need proper lumen. otherwise there is visible contrast
Even with strong projector the reflection parts make not possible to see clear and sharp details. It turns like you can use it as kind of lighting instrument, not display device.
As ggml mentionned, brightness is key… For classic projections I aim for 1000 lumens / 1m wide image, for the organ you will get good results if you double that…
We used 2x 10k lumens projectors for this project: http://joanielemercier.com/grote-kerk/
OK.thanks for tips. I’ll give it a try