Flowing a plate
Holding the plate as a waiter would hold a tray, pour a puddle in the centre, until it covers around 1/4 of the surface.
Then gently tilt the surface so the collodion ‘flows’ to the bottom right corner, then the bottom left, top left and finally top right.
Angle the plate and allow the excess to run off back into the collodion bottle. Whilst the collodion runs off, rock the plate back and forth to avoid run-off lines.
The surface will become tacky after about 20 seconds. Test by placing a finger in the corner. If it leaves a finger print it’s ready to be sensitised
Developing a plate
Under the red light, remove the plate from the holder and hold it waiter-tray-style, emulsion side up.
Using a shot glass or small jug, swiftly pour the developer along the right edge, with the plate angled to the left. As the developer flows over the surface straighten the plate up so the developer pools over the plate.
Gently agitating the plate, allow the developer to react with the emulsion, until highlights, then mid tones, begin to emerge after 15 seconds.
To arrest development, pour fresh water from a large jug gently over the surface until the water runs smoothly off the plate.
The plate is no longer light sensitive.
Varnishing a plate
It’s essential to apply the varnish layer within a couple of weeks of making a plate. Firstly, the silver tarnishes over time and will eventually turn black, and secondly, old collodion will be stripped by the varnish solution and the picture will be destroyed.
Dust the plate using canned air or a very soft brush. Heat the bottle of varnish to blood temperature. A tray of tea lights gives a gentle, even heat. Or a rack placed over a radiator is a good method.
Heat the plate until it’s almost too hot to hold.
Flow the plate using the same technique as with the collodion.
Return the plate to the heat to cook off the excess varnish.
WARNING. The varnish is flammable.
Place on a drying rack. It may take up to two days for the plate to dry completely.
QUICK VARNISH HACK: If you’ve left the plate too long to use sandarac or want a quick varnish, spray with artist’s acrylic varnish - not quite as pleasing a finish but it will preserve your plate.