PBE 2022-2024 Backdrop Design and Fabrication

• The brackets at the frame corners are the keys to the entire system. They are made from nominal 3/4" plywood (actually 23/32") cut into 5 7/8" squares and glued to double thickness - this provides the correct width of the brackets and extra rigidity. (and economy of lumber and cuts.) You could instead use a hardwood like hard maple for the brackets, but plywood largely avoids cross-grain movement problems. Or, it may be better to have brackets fabricated in metal if the fabricator can be more precise. I was skeptical about using metal thinking that the weight of it would be excessive to achieve the same rigidity as plywood. 
• The brackets have to sit entirely inside the verticals/horizontals so as not to create visible interruptions in the fabric.
• Once glued the plywood squares were cut into two equal triangles, re-cut to ensure squareness and notched into an L shape to allow a space for the wingnuts. 
• A high degree of precision is needed for drilling the holes in the brackets.  I designed a jig to ensure uniformity and used a drill bit that was 1/32" larger than the bolt size. So 1/4" bolts and 9/32" drill bit.
• Because you're drilling into the side of a cut on laminated material the drill bit and drill press need to be rigid and not prone to slipping (wandering) sideways.
• Each side of each bracket is identical so there are four holes but only two positions, matching the two positions on the ends of the cross pieces and two positions at the top of the verticals and two in the middle/bottom.

Frame Fabrication

• We used milled Douglas Fir framing lumber in 2"x3" nominal size (1.5"x2.5") but it was actually custom milled from 2x6 lumber because 2x3 is not a common size.
• All sides of the wood had to be cleaned up using a planer and then sander to ensure minimal snagging on the fabric and easy of handling for volunteers helping with assembly.
• Holes are drilled in precise positions to ensure the brackets fasten the cross pieces into exactly the right position at the top and middle of the uprights.

• Ends of runs have one bracket top and one bottom facing inward. 
• Middle run verticals have two brackets top and two bottom, sandwiched on either side with longer bolts. This means there are two bolt lengths.
• The brackets on the bottom face down while the brackets on the top face up. 
• We've found that assembling on top of a run of 6' tables allows easy access and makes it easy for a group of 5-6 people to stand up the entire assembly without racking it too much.
• To ensure the runs are straight once assembled, we added strips of 3/8" plywood to the top using wood screws (a last minute addition but I think it works pretty well.) with the seams of the plywood landing mid-way between the seams on the main frames. (like a brick layer.)
• For interacting with the 8' stage segments you'll need to gauge the foot placement - depending on the stage design the feet may conflict.

• After running through hundreds of samples from various suppliers I arrived at one clear winner in terms of cost/quality.  The fabric we use is "ITY Knit Jersey"  in "charcoal" color, from FabricWholesaleDirect.com. https://fabricwholesaledirect.com/products/ity-knit-jersey-fabric?variant=39460347740275  It naturally seems to not wrinkle ever, it stretches, it doesn't snag or get easily damaged. And dirt seems to be easy to remove for the most part.
• Color wise - we've found it to be a bit of a chameleon - it looked blue/purple in 2022 when there was lots of sky/sun in the room and in 2024 it looked more neutral grey. 
• The fabric (in black) works quite well on the 8' tables as skirting/surface without any modifications. (two layers for each run.) We plan to use it on 6' tables also in the 2026 show - the prefabricated tablecloths are too wrinkly. 
• For the backdrops the fabric is about 5' wide, so we sewed a long seam along one edge to make a giant pillow case type construction. This was actually the most logistically difficult part of the entire fabrication because keeping the fabric clean and evenly feeding it took a lot of hands and tables.  We used a large driveway of a local club member and 6' folding tables, there were 8-10 people helping all at once. 
• One end was a fold, while the other end was sewn vertically - but due to the stretch in the fabric the sewn end isn't super useful. Depending on the length of the fabric versus the length of the run, we found that leaving a "drape" of it leading to the ground actually looks quite nice.
• Once the pillow-case is added over the wooden framework, we simply use "binder clips" to stretch it down around the lower horizontal wooden piece.  About 3 binder clips per 8' section. 
• A selection of black safety pins is useful for securing the ends and cleaning up junctions with the table coverings. 
• Double sided fabric tape can help to ensure where fabric is used as table skirting that it stays in place. 

The Relationship of Light to Our Fabric

• The fabric is not completely opaque - in 2022 we used opaque black pallet wrap over the frames before applying the fabric covering. Without it sunlight will show shadows from the opposite side and be disruptive to the visitor experience. The middle rows in 2022 had the extra layer while the sides against walls did not. (in hindsight we should have done the north run as well due to the lowest section of windows behind it.)
• In 2024, due to the angle of the sun and the new venue we did not use the pallet wrap underneath - this was mostly fine, but we noticed that some low-angle artificial lighting did shine through. It was more apparent in photos than in person but would best be avoided.  
• In 2024 the venue had one set of east-facing windows that cast light into the exhibit on Saturday morning for about 2-3 hours. The runs of trees were set up to account for the natural lighting.  (You can see in the elm photo above that sun on the centerpiece is making it bright enough to penetrate two layers.)
• in 2024 Artificial lighting was added directly vertically above the trees, as precisely as possible. This meant that under artificial light that the light would not be seen through the fabric. Notice the shadow under the stand of the pine below is precisely centered. The lighting highlights the depth of the branching without causing distracting shadows.