ot equally photogenic, some requiring much longer time
of exposure than others. This may be easily observed by exposing the
plate at the same time to a plaster bust and a piece of black velvet,
the first being a much stronger reflector of light than the latter: the
time necessary to produce a well developed image of the velvet being
about six times longer than that required to produce an equally defined
image of plaster. The manner of judging correctly of the time is by
the appearance of impression after it has been developed by the
mercurial vapors. Should it present a deep blue or black appearance it
is solarized or over-timed. This sometimes is to an extent, that a
perfect negative is formed, the white being represented black, and the
dark light.

An object requiring the particular care and attention of the operator
is the proper focus. It is not unfrequently the complaint of sitters
that their hands are represented as being magnified and greatly out of
proportion with the general figure. This is the case also with the
nose and eyes, but in a less degree. As this cannot be wholly
remedied, it is desirous to come as near as possible, and in order to
do this, it is necessary to present the figure in such a position as to
bring it as nearly as possible upon the same plane by making all parts
nearly at equal distance from the lenses. This must be done by the
sitter inclining the head and bust formed to a natural, easy position,
and placing the hands closely to the body, thus preserving a propel
proportion, and giving a lively familiarity to the general impression.
It is not an uncommon fault among our less experienced operators to
give a front view of the face of nearly every individual, regardless of
any particular form, and this is often insisted upon by the sitter,*
who seems to think the truth of the picture exists principally in the
eyes staring the beholder full in the face.

* I might here picture some curious scenes experienced by our operators
Every one is familiar with a certain class of our community whose ideas
of the importance of a free and easy position of the body are too
closely confined with stays, attention to toilet, tightly fitting dress
coats and the like, to admit of being represented as if nature had
endowed them with least possible power of flexibility. To such we
would suggest the following, to be well learned and retained in the
mind while presenting themselves before the Daguerreotype