Year: 1897

page_text: GEORGE FREDERICK WYNNE, Plas Gwyn Minera; near Wrexham Accountant, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to he particularly described and ascertained in and by the following
statement:-
This Invention relates to improvements in Actinometers, and the object thereof is
Firstly, to provide an improved device for timing the exposure of platinoty pe, carbon:
engineer's sun prints, or any other printing process requiring, development to bring
out the latent image, or for testing the speed of sensitive photographic plates or films,.
and Secondly an exposure shutter for use with. the Actinometer described: in. my
Patent No. 10617 of 1893.
The Invention is fully disclosed in the following specification, of which the
accompanying drawings form a part in which
Figure 1 is a plan view of the device which I employ with the hinged lid or cover
of the casing open.
Figure 2 a section on the line 2. 2. thereof; and
Figure 3 a plan view of a metal plate which forms a part thereof..
In the drawing forming part of this specification the separate parts of my improve-
ment are designated by the same numerals of reference, and in the practice of my
invention, I provide a metal casing 5, which is preferably rectangular in form; and the
bottom of which is open, and provided with an inwardly directed flange or rim 6,.
which extends entirely around the same, and the said box or casing is provided with a.
hinged cover 7.
Within the bottom of the box or casing is a plate 8, of opal, ground glass, or other
translucent material,.above which is placed a sheet 9, of thin metal or other opaque
substance. The position of the opal and perforated metal plates may be reversed,.
but the best arrangement is to have the opal plate outside as shewn, as their is then no
danger of the perforations becoming choked up with dirt. In this metal plate are
formed a plurality of rows of perforations which are designated by the reference.
numerals 10, 11, 12 and 13, and said rows are preferably four in number,
and said perforations in each row are graduated in size from one end to the other
thereof, the first and third rows beginning at the right, being preferably larger
than the second and fourth, and above this metal plate are placed two similarly
shaped plates 14 and 15 the first of which is composed of glass, and the other of
opal or some similar translucent material of greater opacity than the other plate.
Above the plates 14 and 15 is a transparent plate 17 of glass or similar material,
and on this plate I place the numerals from one to sixteen inclusive, said numerals
being arranged in two rows, and in such manner that they are directly over. the
corresponding perforations in the rows of perforations 12, and 13, in the plate 9, andi
adjacent thereto, are two rows of letters from A to P. inclusive, which are arranged
in a similar manner, and directly over the corresponding perforations in the rows 10.
and 11, in the plate 9.
These separate rows of numerals and letters are shewn in Figure 1. I also place
1

page_text: in the hinged cover or lid 7, felt or other packing material 21, and said lid or
cover is provided at each end with inwardly directed spring prongs or projections 22
and ordinary strips 23. of sensitive silver "print out paper are placed in said
lid or cover, and held therein by said spring prongs or projections 22, and when
the lid or cover is shut the sensitive strips 23, are pressed into contact with the
hereinbefore mentioned numerals and letters.
When the lid or cover of the box is closed and the opal or translucent plate
exposed to the light, the light passes through the said plate, and the perforations
in the metal plate 9, falls upon the numerals and letters on the plate 17, and
impresses said numerals and letters upon the sensitive strips 23.
have discovered that it is not necessary to separate by an opaque partition,
the light which falls upon one character from that which falls upon another, but
that if the thickness of the glass and opal and the proportion in the size of
the holes in the plate 9, and the characters are properly adjusted, the light from
one hole does not in any way interfere with the printing of any of said characters,
other than the one immediately opposite said hole, although there is only a
transparent or translucent medium between the perforate.l plate and the
characters.
As the greatest amount of light passes through the largest holes or perforations
and falls upon the first figures, and a less quantity upon each of the succeeding
ones the characters over the largest holes or perforations, or those at the right,
are first impressed upon the printing paper and each succeeding figure or letter
afterwards in its regular order. As the greatest variation that can be conveniently
made in the size of the holes in the metal plate will not give sufficient variation to
embrace every kind of printing process from the quickest to the slowest, I extend the
time required for the characters at the left to appear by causing the light which is
admitted through the perforation's in the plate 9, to pass through a thickness of opal
or translucent inaterial 15 instead of through plain glass.
. I preferably let the light which falls on the characters at the right, or the first
sixteen figures to pass throughglass and that which falls upon the characters at
the left, or the sixteen letters to pass through opal.
If a test platinotype, carbon, or other similar print be first tested with the meter
and the figure or letter which is just appearing when the test print is properly exposed
is ascertained any number of succeeding correctly exposed prints can be easily made
whatever be the actinic value of the light by exposing the print and the actinometer at
the same time; and noting when the same test number or letter appears and in the
case of a negative, if the figure or letter is marked upon it, correctly exposed copies
can be made from it at any time by noting the appearance of this figure or letter as
before explained.
When the meter is opened it will be found that the figures and letters printed upon
the sensitive paper are graduated in density, each succeeding one being fainter and
fainter until a certain number or letter becomes the last one readable. When this
letter or number on its appearance corresponds with the time of the correct exposure
of any print, it is called the test number or letter for all succeeding prints from the
same negative and on the same paper.
I may if I so desire dispense with the compound plate of glass and opal shewn as
placed between the perforated plate and the sheet of glass carrying the figures, the
space between the perforated plate and the glass being void and the proper distance
between them being maintained either by packing of the requisite thickness or by a
special configuration of the case or in any other suitable way.
The scale of light however in this case would obviously be shorter than in the way
before described.
The improvement in providing an exposure shutter for the Actinometer described
in my Patent No. 10617 of 1893 is as follows.
When the disc of sensitive paper is being turned to present a new surface for
exposure if the light at the time is very intense there is a danger of the paper being
discoloured before it can be covered by the finger.

page_text: The exposure shutter perfectly overcomes this difficulty in the following simple
manner.
Fig. 4 shews the plan of the Annular Scale of Diaphragms attached to the
revolving glass dial described fully in Specification of Patent No. 10617 of 1893.
To the inside of the glass is attached a shutter 24 of opaque paper or other
suitable material and of any suitable shape.
The length of this shutter is so arranged that when it is turned so as to cover
the wedge-shaped piece of sensitive paper, a small piece of the sensitive paper 25
is visible below the bottom of the shutter. The sensitive paper can then be turned
the requisite distance by observing its movement through the little peep hole 25
at bottom of shutter. The exposure of the paper can then be made at any time by
simply turning the glass and shutter attached thereto and thus uncovering the
sensitive surface.
Having now particularly described and ascertained the nature of ny said
invention and in what manner the same is to be performed, I declare that what I
claim is
1. The herein described Actinometer, the same consisting of a suitable casing
which is open at the bottom and with alternate plates of opal, perforated metal, opal
and glass, and a transparent plate provided with suitable characters which correspond
in position with the perforations in the metal plate, substantially as shewn and
described.
2. The herein described Actinometer, the same consisting of a metal casing, which
is open at the bottom and provided with a hinged cover, said casing being provided
with an opal plate which is placed in the bottom thereof, a metal plate placed there-
over and provided with graduated perforations or holes which are arranged in lines; a
plate placed thereover and composed of two parts, one of transparent and the other of
translucent material, and a glass plate placed thereover, and provided with characters
which are formed thereon, as described, said characters being arranged so as to
correspond with the openings in the perforated plate, substantially as shown and
described.
3. The herein described Actinometer, the same consisting of a metal casing which
is open at the bottom and provided with a hinged cover, said casing being provided
with an opal plate which is placed in the bottom thereof, a metal plate placed there-
over and provided with graduated perforations or holes which are arranged in lines, a
plate placed thereover and composed of two parts, one of transparent and the other of
translucent material, and a glass plate placed thereover and provided with characters
which are formed thereon as described, said characters being arranged so as to corre-
spond with the openings in the perforated plate, and the hinged cover being
provided with means for holding sensitized paper, substantially as shewn and
described.
4. The modification herein described where the compound plate of opal and glass is
dispensed with, the instrument then consisting of a metal casing which is open at the
top and bottom and provided with a hinged cover, said casing being provided with an
opal plate which is placed in the bottom thereof and a metal plate placed thereover
and provided with graduated perforations or holes which are arranged in lines and a
glass plate placed thereover and provided with characters which are formed thereon
as described, the requisite distance between the perforated plate and glass plate
being maintained by packing pieces of suitable thickness or in any other suitable
way.
5. The arrangement herein described for fixing the strips of sensitive paper for
exposure in the lid of the Print Meter consisting of a combination of a pad of
felt or other elastic substance fitted into a lid provided with spring prongs or forks
the paper being clipped between the pad and the prongs by the elasticity of the
former substantially as described.
6. The exposure shutter described, consisting of an opaque shutter of suit-
able dimensions fixed to the cover Glass of Meter in such a manner that the

page_text: sensitive paper of the Actinometer can be screened from the action of the light whilst
it is being moved and afterwards exposed by the partial rotation of the glass
substantially as described!
7: The construction of an Actinometer in which the gradation of the figures
constituting the scale of light is obtained without the intervention between each
figure or letter of an opaque partition for confining the action off the light to tliat
portion of the sensitive surface only which is immediately beneath eacli: individual
aperture in the perforated: plate; thus: greatly simplifying the construction. of tlie
instrumenti