Licht En Zilver
Collodion Fotografie

Category: Process

Varnishing troubles…

Varnishing the plate. It’s one of the most important steps, as nothing brings the plate to life like a nice glossy sheen… And for me, it’s one of the hardest things to get right.


There’s different options. Some people use shellac ( ‘Beetle juice’) , others sandarac (a tree resin) , both dissolved in alcohol. Those are the traditional recipes. Others use a modern varnish called Liquitex. I personally use sandarac, because it is what I was taught, and I do like the process of making the varnish (I’ll create a separate post on that). Also, both sandarac and shellac will definitely last for decades when done well. It’s pretty much proven technology. Time will tell if this applies to using Liquitex as well.

So basically sandarac varnish is resin dissolved in pure alcohol, with some lavender oil to make sure it remains somewhat flexible to avoid cracks later on due to temperature changes. If there’s any difference in expansion between the plate and the varnish, the varnish will crack. The varnish (and the plate) needs to be heated to let the alcohol evaporate, and this is typically done above a flame (alcohol lamp). Flames and pure alcohol don’t mix well.

There’s a couple of problems that can occur. If the collodion is of low quality or when it is too old, the high alcohol content of the varnish will dissolve the image as soon as you pour it on the plate. If that happens, the solution is to add just a little bit of water to make the varnish less strong, and that solved the issue for me (about 1% was sufficient, just add it a bit at a time and test again) Note that the varnish will temporarily become cloudy as you add the water. However, if there is too much water in the varnish, it will result in an overall matte or dull look of the varnished plate. Point to take away here is to use good collodion.

Another problem is the way you pour and heat the plate has a big effect on the result or gloss of the varnished plate. The correct way of doing it is difficult to explain, I can only tell you what worked for me in the end…  To some extent, it seems to be a matter of getting ‘a feel’ for it.

So here’s my process :

heating up the varnish

heating up the varnish

  • Heat the varnish to 38 degrees (Celcius). I use a baby bottle warmer, which works just great. I prefer this over heating the varnish in a test tube, because it enables a consistent temperature for every single plate.
  • Heat the plate above the flame. Try to heat the plate in such a way (especially when using glass) so that it is evenly heated. This is harder than it seems. I heat it to the point where it is still relatively comfortable to hold.
  • I wipe of the dust using a very soft make-up brush.
  • Pour and spread a puddle of varnish on the plate, just like you’d do with collodion.
  • Leave the varnish on the plate for a couple of seconds, don’t immediately pour it off !
  • Then, drain the excess varnish gently. If you tilt the plate too quickly, the varnish will run over itself, and you’ll get ridges.
  • Keep an eye on the plate while pouring off the excess varnish. If you see that diagonal lines start to form, slightly rock the plate while pouring off, and tilt the plate a bit less.
  • When the varnish starts to drip rather than run off the plate, I move over the lower corner to a paper towel to wick off the varnish that builds on the two lower edges of the plate.
  • Put the plate well above the flame ( I start off about 15/20 cm away from it )
  • Keep the plate slightly tilted, drain corner down, to avoid the varnish running back on itself.
  • I keep my thumb against the edge of the lowest corner of the plate which further wicks off any varnish that is running off the plate. This also avoids varnish drops falling in the flame. I keep my middle and index finger on the lower side of the plate. If it gets too warm under there, I’ll feel it.
  • Slowly keep heating the plate, progressively moving the plate closer to the flame. Move it down too quickly, and you’ll set the alcohol on fire, which will most likely ruin the varnish.
  • As the varnish starts to set, you can tilt the plate back into a horizontal position, which makes it easier to apply an even heat across the plate.
  • Heat the plate for a while, until the varnish has completely set. The drain corner should not feel sticky anymore. Don’t heat it past the point where it is not comfortable to hold.
  • Store the plate upright, and in a dust free environment for a couple of days to let the varnish harden out completely.
  • Enjoy the lavendar smell…

If you have some test plates from a shoot, use them as guinea pigs (especially) when starting with a new batch of varnish !  I even cut them (10×8 inch plates) up in 4 pieces to have more testing material…

The main problems I had were caused by

  • getting the plate too hot prior to pouring, or heating the plate too quickly after pouring. This causes small dots, pits actually, to appear, which seems to be caused by water or varnish locally boiling. If you have a lot of them, you get an overall matte look…
  • not letting the varnish rest on the plate for a while before pouring off. It is easier to get an even finish if you give it some time. Don’t rush it !
  • not keeping an eye on the plate while pouring off. If you get lines, you can remedy them if you react quickly as described above.

An illustration of some of the problems I had (sorry for the reflection of the lamp, but it is the only way you can see the issues clearly). Click on the photo to see the description of the problem.