- [voiceover] In 1851 the Englishman Frederick Scott Archer
invented the wet collodion process of making negatives.
This process allowed photographers
to produce finely detailed images on paper
and to print an unlimited number of copies.
These key features were improvements over
the previous two photograph processes,
the daguerreotype
and the calotype.
From 1851 until about 1880
the wet collodion process
became the dominate method for making photographs
throughout Europe and North America.
Producing a wet collodion image
had to be done quickly and efficiently.
This is because collodion, the main chemical used,
will dry up and lose its sensitivity
after about 10 minutes.
Photographers used portable darkrooms,
so the plate could be developed
immediately after it was shot.
The wet collodion process can be broken down
into a number of equally critical steps.
First the edges of the glass plate are smoothed
with a sharpening stone to help
the collodion adhere better to the plate.
The glass is polished with a solvent,
such as rotten stone or glass wax.
Next the glass is carefully cleaned again
to remove any dust particles.
This is important because any remaining particles
will show up as dark spots on the final image.
A mixture of iodides, bromides, ether, and alcohol
are added to the collodion to help make it photosensitive.
The solution is then allowed to age
for (mumbling) a week prior to use.
Using a method called flowing the plate,
the collodion is poured carefully
onto the center of the glass.
The collodion enables the silver nitrate
to adhere to the plate,
so it is crucial that the collodion
covers the entire surface.
Inside the darkroom the photographer dips the plate
into a bath containing silver nitrate,
the chemical that will make the plate sensitive to light.
The plate is left in the bath
for about three to five minutes.
The photographer then removes the sensitized plate
from the silver bath and lays it inside the plate holder.
The collodion side is placed face down
so that it can receive the path of light
once inside the camera.
Any excess silver nitrate is removed from the back.
Once closed the plate holder emits no light,
which allows it to be safely removed from the darkroom.
in the back of the camera the photographer makes
final adjustments to the composition to the image
before inserting the plate holder.
He must make any changes now,
for once the holder is in place
it is no longer possible to focus the camera.
The plate is exposed to light by first pulling
the dark slide out and then removing the lens cap
to expose the plate for the required amount of time.
The lens cap is then placed over the lens
and the dark slide inserted back in the plate holder.
Once closed, the plate holder is removed from the camera
and brought back into the darkroom.
In the darkroom the glass plate
is removed from the plate holder.
Developer is then poured onto the plate.
It is important that the developer is poured
in an even, sweeping motion,
otherwise it will leave ridges and markings
on the final image.
When the photographer is satisfied with the image,
water is poured over the plate
to stop the development.
The exposed and developed plate is placed
in a bath of fixer to permanently preserve the image.
The plate is left in the fixer until it clears.
After removal the plate is washed thoroughly in water.
After the plate is dry it has to be varnished
to protest the fragile image surface from damage.
The plate is heated to facilitate this process.
A clear coat of varnish is applied to the plate,
much as the collodion was.
This must be done very carefully,
since the varnish can accidentally dissolve the image.
Once the plate is varnished a print
can safely be made from it.
Photographers most commonly printed
wet collodion negatives on albumen paper.
This is made by first floating a sheet of photographic paper
on a solution made from egg whites,
then floating it in a tray of silver nitrate.
After drying, the paper is placed in contact
with the negative in a printing frame.
The negative is then exposed to sunlight
and the image emerges during the exposure.
The photographer watches it carefully
to determine when to arrest exposure.
The finished print is called an albumen print.
Colors range from reddish to purplish-brown
and the prints have a lush, glossy surface.
Albumen prints made from wet collodion negatives
remained extremely popular until about 1880
when they were replaced
by more industrialized photographic methods.