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initiated self-imposed quality control and testing in
their manufacture. In the 1850s, after preparing a new
batch of waxed paper negative papers, the British pho-
tographer Samuel Smith, of Wisbech, Cambridgeshire,
for example, would use the front of his house as a test
subject to determine the sensitivity of the new material,
and thus the exposure required. Collodion users would
go through a similar routine to test the rapidity of each
new mix of chemicals.
Despite the primitive chemistry and unsophisticated
technology of the day, the quality of surviving imagery
from the mid-Victorian period is a testament to the skill
of the early photographers, despite the lack of sound
scientifi c underpinning.
However, a widespread lack of understanding of
the relationship between the colour temperature of the
exposing light source, the spectral sensitivity of the
emulsion, the exposure given to the negative, and the
processing to which it was subsequently subjected,
resulted in a range of visual phenomena in the nega-
tives and resulting prints for which photographers had
no ready explanation.
In the absence of simple measuring devices which
would aid the estimation of accurate exposure, develop-
ment was, invariably, continued ‘until the image was
brought out fully,’ however long that might take.
An appreciation of the importance of consistent de-
veloper temperature, did not gain widespread acceptance
until the end of the century. Despite recognition in the
1860s that the activity of the developer changed with
the seasons, no connection was made between that and
the importance of temperature consistency. Instead, it
was suggested (Towler 1864) that a stronger developer
was needed in the winter than in the summer, and that
a more acidic developer was preferable in the summer,
as the acid slowed the developer action down.
The combination of lower actinic values in winter
daylight—causing under-exposure—and cold and
under-active developers, resulted in many negatives
which required considerably extended development
until a printable density was achieved. This introduced
increased fog levels, signifi cant loss of shadow detail,
and a loss of the subtle tonality which those same pho-
tographers could produce in summer.
Perhaps surprisingly, failure to recognize the cause
of the problem persisted into the closing years of the
century with Wall (1897) noting that ‘speaking very
generally, it may perhaps be estimated that development
takes about twice as long in winter as in summer.” Wall
did, however, observe correctly that “under-exposure
should always be avoided, as with these plates or fi lms a
considerable amount of over-exposure can be controlled
in development, but if the light has not acted suffi ciently
on the plate no process of development can possibly
make a good negative of it.” In Wall’s 1897 dictionary,
he devoted several pages to ‘Thermometers and Ther-
mometry,’ but included nothing of their application to
photographic processing! The chemical composition of
the developer, its strength and its rate of activity were
all issues about which individual practitioners held
strong views.
In many instances, good science emerged from heated
debates between practitioners with opposing points of
view, conducted in the meetings of photographic soci-
eties and literary and philosophical societies, or in the
pages of the emerging photographic press. Often dete-
riorating into very personal attacks, these very public
spats helped to progress scientifi c understanding, with
the protagonists returning to their experiments to test
and re-test their theories. The gentleman scientist—the
enthusiastic amateur—seemed willing to endure the
opprobrium of his peers in the cause of defending his
point of view. There was little tangible benefi t to the
protagonists, except by being proved correct, but their
perseverance eventually led to signifi cant progress and
enhanced understanding.
It was only with the advent of industrialization in the
manufacture of photographic materials that good science
acquired a commercial value. Once the manufacture
of emulsions and materials moved from kitchen-sink
to manufactory, consistency and reliability assumed a
greater importance.
Amongst the fi rst to produce ready-to-use gelatin-
bromide dry plates were Wratten & Wainwright in
London. Along with several other manufacturers, their
‘repaid’ dry plates went on sale in the late 1870s, and
were initially met with ‘scepticism and conservatism
by the most eminent photographers’ used to preparing
their own materials from start to fi nish (Werge 1890).
Initial reluctance, on the part of photographers, to ab-
dicate their responsibility for emulsion preparation and
coating to industrial concerns, was only overcome when
those emerging manufacturers could demonstrate that
their products offered benefi ts which the homemade
preparations could not. Those benefi ts—initially more
promised than actual—only really came to be under-
stood and appreciated once the many chemical and
physical components of photography were recognized
as a single system rather than a number of disparate and
unrelated elements.
Key to persuading professional users of the benefi ts
of pre-coated plates was the introduction of scientifi c
control over emulsion preparation, and the design of
coating machines to ensure batch-to-batch consistency.
Manufacturers such as Cadett & Neal, Marion & Com-
pany, and others, quickly recognized the commercial
value of emphasizing the high quality of their materials
and the consistency of results which their careful use
brought to the user.
In working towards an understanding of the holistic