Just when you’ve finally made your first beautiful wetplate images, its time to face up to the fact your going to have to varnish them if you want them to last any length of time. Varnishing is a daunting task and very capable of screwing everything up.
Out of all the Wetplate workshops I’ve participated on, all the books I have read, nothing should be easier than varnishing a wetplate image. Ive been taught by the best, watched endless youtube videos on perfect varnishing techniques. Its quite sedate, forgiving and straightforward – that is until you try it yourself with an aluminium plate. Welcome foggy, misty, matt, patchy, blotchy mess.
The general gist of varnishing is to first heat up your plate until its blood hot using an alcohol lamp, although many say to go as hot as you can comfortably hold. You then pour on the sandarac varnish and tip it from corner to corner until all the plate is covered. You then drain off the varnish, wick the corner on a paper towel and start to reheat the plate upon the flame to cure the varnish.
Ive varnished hundreds of plates now and I had it down to a very fine black art that worked well 60% of the time. It involved working at a very fast rate of speed and not letting the plate have a chance to cool. The biggest drawback to working fast was if you return your fresh varnished plate back to the flame too early – it catches fire. I was working at a very dangerous fine line between not letting the aluminium cool down, and also not letting it catch fire. That was until I discovered a rather obvious trick.
The problem seemed to be the aluminium cools down too fast and by the time its reached the flame for the varnish to be cured, its already cold. It is these temperature changes that causes many issues related to a matt, blotchy surface. My new solution; simply place a piece of thin glass the same size as your tintype underneath it for the whole operation. Hey presto everything now should work perfectly and you don’t need to rush.
I recommend working fairly slowly, heat up your varnish in a double boiler of hot water. Heat up the tintype with the glass underneath it until its starting to get uncomfortably hot. Now pour on the varnish as you would collodion but then let it sit for several seconds on the surface once fully covered. Pour off the excess varnish holding the plate vertically with one corner dripping into the waist bottle. Hold it there until its stopped dripping and then carefully wick off the excess varnish.
Return the plate to the flame still holding it with the corner down. Keep it high off the flame and gently reheat the plate. Do not let the flame touch the plate, it should be comfortably above the flame. Move the plate around to heat the surface equally. After a minute of so, hold it horizontal and continue evenly heating the plate. I carry on heating until its starting to get too hot to hold and then I place it on a rack to dry.
Varnishing has suddenly gone to something I avoid for as long as I dare, to my favourite part of the process. I hope this advice may help somebody else also baffled by the varnishing of tintypes.