Scientific American Supplement, No. 586, March 26, 1887Various
Science
Scientific American Supplement, No. 586, March 26, 1887
Various
Science -- Periodicals
As an engineer, Whistler's works speak for him. He was eminently a
practical man, remarkable for steadiness of judgment and for sound business
sense. Whatever he did was so well done that he was naturally followed as a
model by those who were seeking a high standard. Others may have excelled
in extraordinary boldness or in some remarkable specialty, but in all that
rounds out the perfect engineer, whether natural characteristics,
professional training, or the well digested results of long and valuable
experience, we look in vain for his superior, and those who knew him best
will hesitate to acknowledge his equal.--_Journal of the Association of
Engineering Societies_.
* * * * *
PRINTING LANTERN PICTURES BY ARTIFICIAL LIGHT ON BROMIDE PLATES FROM
VARIOUS SIZES.
By A. PUMPHREY.
[Footnote: Read before the Birmingham Photographic Society. Reported in the
_Photo. News_.]
There can be no question that there is no plan that is so simple for
producing transparencies as contact printing, but in this, as in other
photographic matters, one method of work will not answer all needs.
Reproduction in the camera, using daylight to illuminate the negative,
enables the operator to reduce or enlarge in every direction, but the
lantern is a winter instrument, and comes in for demand and use during the
short days. When even the professional photographer has not enough light to
get through his orders, how can the amateur get the needed daylight if
photography be only the pursuit in spare time? Besides, there are days in
our large towns when what daylight there is is so yellow from smoke or fog
as to have little actinic power. These considerations and needs have led me
to experiment and test what can be done with artificial light, and I think
I have made the way clear for actual work without further experiment. I
have not been able by any arrangement of reflected light to get power
enough to print negatives of the ordinary density, and have only succeeded
by causing the light to be equally dispersed over the negative by a lens as
used in the optical lantern, but the arrangements required are somewhat
different to that of the enlarging lantern.
The following is the plan by which I have succeeded best in the production
of transparencies:
[Illustration]
B is a lamp with a circular wick, which burns petroleum and gives a good
body of light.
C is a frame for holding the negative, on the opposite side of which is a
double convex lens facing the light.
D is the camera and lens.
All these must be placed in a line, so that the best part of the light, the
center of the condenser, and the lens are of equal height.
Public-domain text, read in full here on John Shaqi.
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