McKean delivered a lecture to the Edinburgh Photographic Society on 7 June
The Modern Photographer - his Power and Appliances.
McKean appreciated the progress that had been made in photography.
the mysterious orbs of heaven and the rolling clouds, from Alpine heights
to the deepest caverns of the earth, the camera is capable of revealing to
the eye of man a mighty store of knowledge ...
we owe a deep debt of gratitude to those noble pioneers of the art who
have placed in our hands such a marvelous power in so simple a form as
that of the gelatine dry plate."
he regretted the fact that so few had mastered the process of making such
a plate. He encouraged photographers to make their own plates,
intend this evening to give you a practical demonstration of my mode of
working; and I venture to say that after two years' work without a
negative bath, and daily using my own plates, there is no reasonable
excuse for even the humblest of the profession not to become their
own plate-makers. ... ...
bottles, a bowl and jam pot contain the simple ingredients for the
production of ten ounces of emulsion.
the first bottle we have -
the second bottle we have -
jam pot contains -
(Nelson's No 2)
McKean went on to describe his process:
- We now place in the bowl half an ounce of gelatine. (I use
equal proportions of German and Nelson's No 2.), and, covering it with
water leave it to swell till we have mixed and digested the emulsion which
we will now proceed to do.
- Placing our two bottles and jam pot with their contents in a pan
of sufficient size, along with an ordinary bath thermometer and a little
water, we raise the temperature to 140 degrees Farh. over a fire or Bunsen
burner, and, shutting out all actinic light from the room, we take in our
hand the bottle containing silver nitrate, and in the other a glass rod -
glass or silver spoon.
I prefer a horn spoon ... ... we begin by using
the handle to agitate the solution of gelatine and iodide.
We next introduce in a gentle stream our solution of silver nitrate a
la Captain Abney.
We have now our old friend the iodide of silver in contact with our new
love, gelatine though they do not seem quite to agree with each other, the
iodide clinging to the handle of the spoon as if anxious to avoid the hot
treatment to which it shall shortly be subjected; but immediately we
introduce the solution of bromide and chloride harmony is restored.
Our emulsion is now in the first stage of sensibility, and may, after a
thorough wash and addition of the rest of the gelatine, be considered in
its infancy, capable of receiving impressions of the outward world, though
a little too slow for these days of spring shutters and photographic
We have, however, a simple and effectual means of adding this desirable
degree of sensitiveness, namely the process on boiling. Before doing
so, it is well to withdraw a few drops of our emulsion, and spreading them
on a glass plate, we may by transmitted light mark the difference between
its youthful bloom before and its grey maturity after boiling.
So far we have accomplished our task of making what we would term a modern
emulsion. We will now cover with a lid the dish containing it, round
which I place a cloth to keep it from coming in contact with the sides of
the pan in which we intend boiling it.
Covering all with the lid of a pan, and re-lighting our Bunsen burner ...
leave it to "cook" as long as in the present occasion we may
find it convenient. I usually allow it thirty minutes."
let me ask if there is anything so far as we have gone to debar anyone
with moderate intelligence from the independent position of having at his
demand not only as quick plates and reliable as any in the market, but
plates suitable for all circumstances?
the pot continued to boil, he said:
Thus far it may be said the process is easy and clearly understood; but
our task is not yet done, nor is the contents of the pot sufficiently
cooked. So to sharpen your appetites till that is ready I will say a
little on ... ... a quick and ready means for drying your
plates after they are coated ... ... I plied the
tools to the formation of the drying cupboard now here before
you. ... ... I usually coat my plates
after business hours and they are ready for use the next morning ...
Previous to stopping the boiling operation we shall drain the water from
the bowl of gelatine, and, turning out the gas under the pot, withdraw the
dish of cooked emulsion and replace it with the bowl.
After stirring the emulsion for a little we shall examine a few drops
through a glass plate, and comparing it with the first, we find it has
changed from an orange to a grey-blue colour - a change which I do not
pretend to explain. It is enough for out purpose to know that it has
become more sensitive to light, and in this state I decant it right into
the bowl, and in a few minutes the gelatine is dissolved.
I now leave it to "set" all night, and in the morning squeeze it
through coarse canvas into a can of water, over which I tie a piece of the
finest material. At the bottom of the can is drilled a small hole,
through which is passed a rubber tube, forming the simplest and cheapest
washing apparatus yet invented. ... ..."
finally, coating the plates:
now begin the operation of coating the plates by getting everything in
In our pan filled with hot water, place a bowl, in which the emulsion is
transferred from the washing apparatus when it will quickly be dissolved
Over a second bowl I stretch two plies of fine cotton, through which I
filter the emulsion, and it is ready for use. For this operation the
only addition to our appliances will be two levelling stands and two
plates of thick glass. Placing one on the table at the left and the
other within arm's length of the cupboard, with the horn spoon in hand
... The spoon contains perhaps three times the emulsion
necessary to cover the quarter-plate in my hand; but pour it all on, and
you need no glass rod to conduct it to the edges of the plate; then
pour off the surplus into the spoon, and return it to the bowl.
... go on with another ... ... By this
time the first plates will be thoroughly "set" and may be placed
in the cupboard. ... ...
you may return to rest with the satisfaction of
knowing that a batch of cheap and reliable plates will be ready for the
first sitter in the morning."