Picture framing
Picture framing turns up in 2 fields: powder coating, waterproofing. Here is what it means to the people in each one.
Picture framing in powder coating
A visible border of heavier or darker coating around the edges of a flat panel.
Edges concentrate the electric field, so they collect more powder than the middle of a panel. The extra film shows as a frame of different gloss, texture or color, worst on metallics, candies and textures. Lower kV, more gun distance and fewer passes on the edges reduce it.
"Panels are picture framing bad, edges are a shade darker, back off the kV on the autos."
Picture framing in waterproofing
A grid-like pattern of ridges visible on a roof surface that outlines the insulation boards underneath.
A visual condition where the roofing membrane forms raised, rectangular outlines that mirror the joints of the underlying insulation boards or roof deck panels. It is typically caused by building movement, thermal contraction of the membrane, or moisture vapor escaping through the board joints and pushing up against the membrane. While often just an aesthetic issue, severe ridging can stress the membrane and cause premature failure.
"You can see the picture framing across the whole roof, tracing every single piece of polyiso."