Sequence viewing > Index - Alternative Photo Emulsions - Resource - ©
Photographic Processes - (Hand
made photographic -emulsions and processes)
- Manganese Lactate Printing
While there are some advantages
to this process, it can be tricky to work with.
It is an inexpensive process
that uses non toxic chemicals but produces extremely archivally stable
images. This process is unique in that it produces a positive image,
so if you desire a positive image, you will need to work with a positive
transparency. Making photograms for instance will not produce the normal
X-Ray negative like images.
By adding microbial cultures
to milk it makes it go sour, and converts lactose to lactic acid.
11.5 Grams of Potassium permanganate
: Before use, read Health hazards:.
28 ml of Lactic acid : Before
use, read health hazards
8 grams of Glucose : Before
use, read health hazards
It is important that these
steps are follow carefully! Wear eye and other protection etc. Do this
in subdued well ventilated area. While the chemicals are not toxic,
during the mixing there is great heat generated, and the mixture can
leave a stain on the hands.
Dissolve 11.5 grams of potassium
permanganate in 100ml of distilled water. Because the lactic acid generates
a great deal of heat as it combines with the potassium permanganate,
once this first solution has dissolved, place the container in a larger
container of cold water.
The Lactic acid
( 28ml) is combined with the potassium solution one drop at a time.
It is liable to bubble and fume strongly and should be done in a safe
environment. Wear eye and other protection like gloves etc. to do this
in subdued well ventilated area. The lactic acid can be combined via
an eye dropper, or run down a glass rod. A hollow glass tube used for
scientific applications is ideal.
Handle it carefully.
Continue to mix
well between each drop. Once all the lactic acid has been mixed, and
the bubbling has ceased, the liquid should have a rather thick purple
brown consistency. Be aware that while Lactic acid is relatively stable
it deteriorate after about 5 years.
Mix the final component.
8 grams of glucose in 30ml of hot distilled water, which is then left
to cool and then filtered to take out any remaining crystals or irregularities.
This is gently combined with the mixture. Failure to filter out these
small crystals increases the chance of fish eye when the emulsion is
coated on to the paper.
Coat paper or support
base as appropriate in subdued or safe light and then place in a dark
area to dry. Because the emulsion is a dark purple brown colour it is
very easy to see the coating progress on the paper base. despite the
apparent thickness of the emulsion it is actually quite thin and requires
brushing in several directions to obtain an even coating. Once the emulsion
has been brushed on with a brush, leave it to sit for a minute or so
and then even out the coating with a foam brush. If the glucose crystals
are not filtered from the mixture there is a good chance that fisheyes
will appear on the emulsion surface as it drys.
The image is solar
contact printed as for the Van Dyke Brown and Cyanotype. On a bright
sunny day the exposure will be about 4min to 15 mins. You will need
to do a test exposure so coat enough spare paper to allow for this.
Be aware that a positive process like this reacts in a different manner
than the standard photo-processes. The areas of the image that are too
light will be so because they received too much exposure, darker areas
are dark because they received a lesser exposure.
If the process is working,
you will notice a thin negative appearance as well as a heavier positive
image on the brown coating.
After the exposure the image
needs to be developed. This is done in a saturated solution of aniline
sulphate which produces a green positive image. Development takes about
30 seconds at 20 °C and works by bleaching the areas exposed to
light while colouring the remaining areas. Once the process is complete,
no fixing bath or clearing bath is necessary.
However the print should
be washed for in continuously running water for 10mins before drying
in the normal manner.
By adding a few drops of
ammonia (Before use, read Health hazards) to this solution the print
can be developed up with a violet colour.
By adding orthotoluidine
sulphate and a few drops of hydrochloric acid (Before use, read Health
hazards)a Deep blue colouration can be obtained. For a normal image
tone, use a solution of paraminophenol.
Want to learn more? - do a workshop or one on one with Lloyd Godman