IMPROVED METHOD OF AND APPARATUS FOR TAKING PHOTOGRAPHS BY ARTIFICIAL LIGHT
Year: 1884

page_text: COMPLETE SPECIFICATION.
I EUGEN HIMLY, late captain a resident of the City of Berlin, Kingdom of
Prussia, Empire of Germany, residing at N° 54 Zossener Street, do hereby declare
the nature of the said Invention for "IMPROVED METHOD OF AND APPARATUS FOR
TAKING PHOTOGRAPHS BY ARTIFICIAL LIGHT" and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
For producing good photographs it is necessary to have the object to be
photographed in a light in which it is most distinctly visible and most usually
seen.
This light is, as is well known, best afforded by diffused day-light, which may
either be afforded naturally, giving more light on the one side than the other,
according to the time of day chosen or artificially by means of screens, blinds,
mirrors and the like, so as to illuminate the object from all sides to a moderately
varying extent.
In the same manner that it is necessary to prevent the direct or regularly
reflected rays of the sun from striking the object to be illuminated (unless special
effects are desired to be produced) it is also requisite to a still greater degree, to
prevent the direct or regularly reflected rays of light from a powerful artificial
source of light from striking the object to be photographed.
For obtaining the irregular reflection of rays from powerful sources of light, so
as to produce an artificially diffused light analogous to that of day-light it has
hitherto been customary to employ as the most perfect means attainable intensely
illuminated white surfaces, either plane or concave, not acting as mirrors, which
reflect the rays divergently in the general direction of the object to be illuminated.
These illuminated surfaces can also consist in dulled sheets of glass through which
the rays from a number of sources of light are caused to pass divergently.
The diffusion thus obtained is however but little analogous to that of day-light,
as the direction of the rays still remains more or less one sided, and consequently
the photographic pictures obtained by these means have easily discernable strongly
one sided illumination.
Another usual method of a comparatively perfect nature, for obtaining an
illumination analogous to that of day-light consists in the use of several sources of

page_text: light shaded by opal globes arranged round the object to be photographed, which
together with the photographic apparatus is mounted on a revolving turn-table.
Independently of the question of the expensive nature of this arrangement,
requiring specially careful attention to the several sources of light, it is not frec
from imperfections of illumination due to the fact that in addition to the rays
that are irregularly reflected in the desired manner by the small surfaces produced
by the clouding of a glass globe, many rays pass through the glass which, in
consequence of the varying absorbing or refracting powers of the glass, and also in
consequence of the want of parallelism of the glass surfaces produce light and dark
spots on the object.
My present Invention relates to a method of and appliances for producing
artificial illumination as analogous as possible to the action of day-light, consisting
mainly in the employment of a mechanically moved illuminating screen which
reflects the rays from one or more powerful sources of light irregularly in the
direction of the object to be photographed but which entirely diverts the direct or
regularly reflected rays of such sources of light from such object, the movement of
the said screen being effected during the whole time of exposure either through a
certain are round the stationary object to be photographed, or through a straight
-line-past-the same. By this method I obtain firstly, by means of the construction
of the illuminating screen, an illuminating effect analogous to the action of diffused
day-light and free from shadows or excessively-strong-shadows;-and-secondly, owing
to the quicker or slower advancing motion of the screen, regulated according to
requirements, I obtain a moderate lateral gradation of the illumination of the
object, similar to that of day-light. In particular I am enabled by this method to
prevent the-too-powerful-illumination of one side of the object while another side
has to be exposed for a longer time in order to develop deeper shadows.-
The appliances which I employ for carrying out..my said process, consist firstly
in tho illuminating screen, and secondly in the mode of applying and actuating the
same. The illuminating screen is shewn in Figs. 34-3b, 3c, and Fig. 4 of the
Drawings, as also in combination with the appliances for its instalation and
movement, in Figs. 1 and 2. Fig. 3 shews a front view, Fig. 3b a plan, Fig. 4 also
a plan in which is shewn the action of the irregular reflection in a horizontal plane
of the direct rays from two sources of light a and a' and of the reflected rays from
two mirrors. Fig. 3c shews a vertical section through the illuminating screen,
dividing it into two symmetrical halves. The illuminating screen forms a large
semicircular niche with domed top which is closed at bottom by a semicircular
reflecting surface adjustable on a horizontal axis, and in which two separate lateral
niches are formed by means of vertical dwarf walls fand f¹, such niches containing
the two powerful sources of artificial light u and a¹.
Consequently direct rays or rays reflected from the mirrors b b do not pass
outwards but only on to the surfaces of the illuminating screen as also upon the
more or less inclined adjustable bottom surface d, these surfaces being throughout
of a dull white colour, so that they can only reflect the rays irregularly.
The exclusively diffused rays of light passing from the illuminating screen
consequently surround more or less the object to be illuminated, according to its
distance from the screen while there is no central less illuminated core in such rays
of light, such as is produced in illuminating screens of present construction with a
single source of light in the axis thereof, by the use of a shield or disc for
intercepting the direct rays of light, and which cause difficulties in the choice of
position of the object to be illuminated.
The number of sources of light employed in combination with my illuminating
screen is not limited; there may be only one, or two or more arranged in an
analogous manner. The adjustment of the bottom surface d on a horizontal axis
has for its object to distribute the light to a greater or less degree to the lower parts
of the object to be illuminated.
Of the constructions that can be employed for effecting the motion of the
illuminating screen during the duration of the exposal, two more particularly

page_text: suitable ones are shewn at Figs. 1 and 2. Fig. 1 shows the attachment of the
screen to the end of the arın of a crane turning on a vertical axis.
The object to be illuminated is situated near to and underneath the centre of
motion of the crane, so that the illuminating screen is caused to move in a circular
path round the object by means of any suitable mechanism. Or, according to the
arrangement at Fig. 2 a semicircular rail is suspended from the ceiling of the
studio, on which rail the screen is made to run by means of rollers, being moved
to and fro by cords. Both in the arrangement at Fig. 1 as also in that at Fig. 2 the
path in which the screen is caused to travel may be of a variously curved, or more
or less straight or inclined form.
For particular purposes I also employ an arrangement by which the illuminating
screen while moving along its path, also has a motion round a vertical axis
imparted to it, so that it may maintain a parallel position at every point of its
path.
I also in some cases employ as an auxilliary to the above described method and
appliances, a lateral reflecting screen g of a conical or concave form mounted so as
to turn on a vertical axis, which is employed to assist the action of the travelling
screen in causing that side of the object on which such lateral screen is situated to
be more strongly illuminated. As only diffused rays fall upon this screen it may
consist either of an actual mirror or of a deadened surface for irregular reflection.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. The method of illuminating photographic objects during the exposal by means
of irregularly reflected rays of light from one or more moving sources of artificial
light, substantially as herein described.
2. The construction of an illuminating screen such as shown in Figs. 3º, 3b
and 3, and Fig. 4, of the Drawings, operating in combination with one or more
sources of light a a¹, arranged behind lateral screens ff whose direct rays of light
or whose rays regularly reflected from mirrors b b, can ouly pass by irregular
reflection from the illuminating screen to the object to be illuminated, also, in
combination with the said screen the use of a flap d d with irregular reflecting
surface, adjustable on pivots c and forming the bottom surface of the screen.
3. The use of a rectilinear or semicircular or otherwise curved path or rail upon
which the illuminating screen is moved by mechanical means during the time of
exposure.
4. The use of a crane or swinging arm for imparting the required motion to the
illuminating screen.
5. The use in combination with the method of illuminating set forth in the first
claim, of a stationary adjustable lateral auxiliary screen, having a perfectly or
imperfectly or irregularly reflecting surface, and which is caused to reflect more or
less of the irregularly reflected rays of the travelling illuminating screen according
to the momentary position occupied by the latter.