It now works as determinate checkbox, where a checked state produces *=yes and an unchecked state produces no tag.
spelling correction to match tag from OSM wiki. https://wiki.openstreetmap.org/wiki/Tag:craft%3Dphotographic_laboratory
Using disconnect on a closed way can break areas.
We need to think about how to best integrate these; just dumping them into a huge list of overlays is not a good approach.