Category: Collodion

This is the notebook for wet plate collodion process I’m experimenting

First come the chemistry

There are 5 solutions to prepare in order to make wet plate collodion. Note that for all of those preparations, it is recommended to use gloves. Especially when manipulating silver nitrate.

• The collodion
• The silver bath
• The developer 
• The fixer
• The varnish

The Collodion:

• Equipment:
  • scale (accurate to 0.1g)
  • 2 beakers (glass)
  • ground-necked flask or any bottle that can close properly (glass)
  • pipette (glass)
  • a glass stick to agitate

• Chemicals:
  • Collodion 4% : 45ml
  • ethanol 95% : 55ml
  • distilled water : 1 to 3 ml
  • potassium Iodine : 0.9g
  • potassium bromide : 0.5g

• Preparation
  • Pour 90ml of water in the flask, and mark the level
  • In the beaker, add 2.5 ml of distiller water
  • Add the potassium iodine and stir until it dissolved
  • Add the potassium bromide and stir until it dissolved. Those salt are very difficult to dissolve, it will take some time. It helps to heat a little bit the solution. Eventually add 0.5ml of distilled water to help. Too much water and the collodion might not stick properly to the plate or crack when it dries.
  • Add the 55ml of ethanol in the beaker, and transfer it to the flask
  • Shake it and make sure the solution is clear. If not, add one or two drops of water and shake it again.
  • Add the collodion in the flask up to the 90ml mark and close it.
  • Shake for 30 second.
  • Put a label with the date on the flask and let it rest in a luminous place without direct sun for 5 to 10 days. Here, a white precipitate will appear after one or two days.
  • After 5 days, you can gently transfer the solution in another flask  to get rid of this precipitate.

• Notes:
  • The Collodion will last about four month on the shelf. After that it turns orange/red and is no longer usable. 
  • With 100ml of collodion you can coat about 20 4×5′ plates.

The silver bath:

• Equipment:
  • scale (accurate to 0.1g)
  • two glass beakers
  • A dark glass bottle
  • a glass funnel
  • some paper filters (coffee filter works fine)
  • cotton cloth
  • pH paper

• Chemicals:
  • distilled water : 100ml (or more depending of the size of your tanks to sensitise the plates)
  • Silver nitrate : 10g (or a 10% ratio with water if you use need a bigger volume)
  • Nitric acid : you might use a few drops

• Preparation:
  • pour the distilled water in a beaker and dissolve the silver nitrate
  • use the funnel and the paper filter to filter the solution in the second beaker
  • rinse the first beaker with distilled water
  • put some cotton cloth below the paper filter in the funnel and filter again in the bottle.
  • Check the pH and adjust with nitric acid until you get a  pH between 3.5 and 4.5

• Notes : 
  • When you are using a brand new bath, it must be activated the day before you take the pictures by putting a plate with collodion into it over the night. It actually works quite ok after two hours of activation.
  • Over time, the bath got some impurities, so you need to filter it from time to time. It is also possible to perform a sunning. Expose the bottle to the sun (one day during summer, 2 to 3 days during winter). This will isolate the impurities and they will fall at the bottom. then you can simply filter the bath again.
  • The volume of the bath reduce with each plate which is sensitised as some of it goes with the plate.

The developer:

• Equipment:
  • a scale
  • a glass beaker
  • a glass bottle
  • a glass funnel
  • paper filter
  • cotton cloth

• Chemicals:
  • distiller water : 250ml
  • iron sulphate : 10g
  • ethanol : 13ml
  • nitric acid : 8 to 20 drops. It helps to slow down the developer so the operator have the time to see and stop the development in time. 20 drop is good for beginners.

• Preparation:
  • pour the water in the beaker
  • add the iron sulphate and stir until it dissolve
  • add the ethanol
  • filter the solution several times (3 to 4) with the coffee filter and a last time with the cotton cloth below the coffee filter in the final bottle.

• Notes : 
  • The developer will last a month on the shelf.

The fixer:

• Equipment:
  • A 1l glass bottle
  • a scale

• Chemicals:
  • water : 1000ml 
  • sodium hyposulfite : 200g

• Preparation:
  • mix the sodium hyposulfite and the water in the bottle.
  • close and shake

• Notes : 
  • Any commercial hyposulfite fixer will do the job. you will use it stock.

The Varnish:

• Equipment:
  • scale
  • A glass beaker
  • glass bottle
  • a glass funnel
  • paper filter
  • cotton cloth

• Chemicals:
  • ethanol : 100ml
  • Saradanque gum : 12g
  • lavender essential oil : 8ml

• Preparation:
  • in the beaker, dissolve the gum in the ethanol
  • filter the solution several times (3 to 4) with the coffee filter and a last time with the cotton cloth below the coffee filter in the final bottle.
  • add the lavender essential oil

• Notes:
  • This varnish will fit glass plates. As it must be heated.
  •  For plastic plates that cannot be heated, it is possible to use a gum laquer varnish. It is a 15% solution of gum laquer dissolved in ethanol. It will be applied on the plate while it is still wet after rinsing the fixer (I haven’t tested this one yet). So far, I have replaced the saradanque gum with gum laquer, but it produces a very dark varnish and we barely see the picture on the plate after varnish.

Now we are ready to take a picture. But not so fast.

First we will have to setup the frame. We assume here you’re using a large format camera. It is also possible to use a TLR for instance, in that case, you would frame the picture after the camera is loaded with the plate. But for now let’s use a large format like 4×5 or any other large format. The good thing here is that you can compose the picture on the ground glass and come back later.  A few things to remember about light and collodion:

• If you plan to use the sun, it moves really fast and the condition of light you have when you compose might be different when you are ready to take the picture.
• Collodion is not sensitive to red light.
• tungsten light are very inefficient
• prefer daylight lights with high power
• Temperature over 6400K are a good fit
• Fluo tubes or CFL also works fine.

Now we have the camera set and ready to snap, it’s time to prepare the plate.

Clean the plate:

• if using a glass plate, put it in a boiling mix of water and white vinegar. Clean with a sponge and rinse with distilled water.
• Let it dry
• Clean with Ethanol and blow the dust.

Coat the plate:

• Pour a good quantity of collodion on the plate until the edge of the circle almost reach one edge of the plate.
• Choose one corner and slowly make the collodion reach that corner.
• then by applying a circular movement, go to each of the remaining corners. The trick is that the collodion must not go over the same spot twice so you get an even coating.
• At the last corner, pour the surplus back in the flask. Apply a rotation movement with the corner as the center.
• Wait 20 second that the collodion stick on the plate
• Turn on the red light and turn off any other light.
• Put the plate in the silver bath for 3 minutes.
• Take it out and drain the edge of the plate on some tissue paper.
• Put the plate in the film holder.

Take the picture:

• Mesure again the light
• Check the focus one last time and cog the shutter.
• Insert the film holder and expose.

Development:

• Under red light only , take the plate out of the holder
• Pour the developer directly on the plate. You must assure that you got some developer all over the plate in a minimum of time (less than a second).
• Watch carefully and as soon as you can see the midtones, stop the development by pouring running water on the plate.
• Then put the plate in the fixer bath until the image clears.
• Then wash under running water (10 minutes ??)
• make a final wash with distilled water.
• Let the water drain
• Dry the plate with a spirit lamp.

Protect the picture:

As the picture on the plate is really fragile, we may want to protect it with a varnish. It will make it easier to manipulate and also prevent the silver from oxidising which may darken the image over time.

• heat the plate with a spirit lamp up to the point you can barely touch it, but still you can.
• use the same method as for coating the plate with collodion, using varnish instead.
• Pour the surplus back in the bottle.
• dry the edges on tissue paper.
• let it dry and harden it with the flame of the spirit lamp.