[0001] The present invention relates to a method of making a transparent photographic panel
like a slide by using a plurality of photographic prints of the same size
'reproduced from the same negative.
[0002] A transparent photographic panel can be obtained by applying a photosensitive emulsion
onto one side of a base such as a plastic film or a glass plate and then subjecting
the photosensitive emulsion to exposure, development and fixing. However, the photographic
panel thus obtained is insufficient in both contrast and colour density, so when it
is to be used for ornamental or advertising purposes, it is necessary to illuminate
the panel from the back, or else, the panel will be dull and dark making it impossible
to see the display clearly. In the case of photographic paper, illumination from the
back is not necessary, but since it relies on only reflected light, the display is
insufficiently bright.
[0003] It is the object of the present invention to provide a method of making a photographic
panel capable of not only exhibiting a good display effect with reflected light alone
by illumination from the front but also exhibiting an even better display effect by
illumination from the back.
[0004] Accordingly, the present invention provides a method of making a photographic panel,
comprising making at least two photographic prints of the same size from the same
negative, applying adhesive to their surfaces and onto one side of a separately provided
transparent base, laminating said base and a first one of said photographic prints
so that the respective adhesive-applied surfaces are in face-to-face relationship,
thereby bonding the two together, then removing the backing sheet of said one photographic
print, laminating and bonding the second of said photographic prints onto said first
photographic print so that their images are aligned, and then removing the backing
sheet of said second photographic print.
[0005] One embodiment of the invention will now be described by way of example with reference
to the accompanying drawings in which:
Figures la and lb are explanatory views showing manufacturing steps of the method
of the present invention;
Figure 2a is a longitudinal sectional view of part of an intermediate-step product
obtained in the present invention;
Figure 2b is a longitudinal sectional view of part of a photographic panel completed;
and
Figure 3 is a longitudinal sectional view of part of a photographic print used in
the present invention.
[0006] Referring first to Figure la, the reference. numeral 1 denotes a transparent base
formed of a plastic material such as acrylic resin or polyvinyl chloride resin, and
the numerals 2a and 2b denote photographic prints of the same size reproduced from
the same negative.
[0007] The photographic prints 2a and 2b have been obtained by using an ordinary photographic
process of enlarging, developing, fixing, water-washing and drying steps in known
manner. Therefore, each of the photographic prints 2a and 2b comprises, for example
as shown in Figure 3 a paper backing sheet 11, an intermediate layer 12, an emulsion
layer 13 and a gelatin layer 14, the image being formed in the emulsion layer. The
intermediate layer 12 is formed of baryta or polyethylene, and in any case, it has
a milk-white colour for improving the clearness and whiteness of the image. In the
first step shown in Figure la, a water-resistant adhesive is applied by spraying or
other suitable means onto the back of the base 1 and the surfaces of the photographic
prints 2a and 2b (the surfaces of the respective gelatin layers 14), and then dried.
[0008] Referring now to Figure lb, there is shown a second step in which the photographic
print 2a is laminated to the back of the base 1 by utilising the adhesive applied
to each of them. Since the adhesive layers formed on the base 1 and the photographic
print 2a are already dry, the bonding of the two is effected by first applying a suitable
solvent onto the surface of each adhesive layer and then contacting the two closely
with each other. Thereafter, the paper 11 of the photographic print 2a is removed..
This can be done easily, for example, by first tearing off the paper 11 mechanically
and then removing the remaining paper fibres by using a disintegrator such as an aqueous
sodium hydroxide solution or the like. This third step affords an intermediate step
product comprising the gelatin layer 14, emulsion layer 13 and intermediate layer
12 which were bonded to the back of the base 1 through the adhesive layer 21, as shown
in Figure 2a.
[0009] The fourth and fifth steps comprise laminating the photographic print 2b to the back
of the intermediate step product (i.e. the back of the intermediate layer 12) shown
in Figure 2
ii in the same manner as in the second and third steps and then removing the paper
11. In laminating the photographic print 2b in the fourth step, it is necessary that
the image of the print 2b be aligned accurately with the image of the already laminated
photographic print 2a.
[0010] The photographic panel obtained through all of the steps described above has eight
layers - adhesive layer 21, gelatin layer 14, emulsion layer 13, intermediate layer
12, adhesive layer 22, gelatin layer 14, emulsion layer 13 and intermediate layer
12 - laminated in this order to the back of the base 1, as shown in Figure 2b. Since
the images in the two emulsion layers 13 are aligned accurately with each other, there
are obtained high contrast and density, which, coupled with the milk-white translucence
of the intermediate layer 12, permit the photographic panel to present the same external
appearance as in ordinary prints, and further permit the panel to exhibit a visual
effect equal to that of a slide when the panel is illuminated from the back by means
of a fluorescent lamp or the like.
[0011] In the above described embodiment, two photograhic prints were laminated to a single
base, but in the case of a low contrast of print or in case a special visual effect
is to be obtained, three or more photographic prints may be laminated together. Furthermore,
when the intermediate layer of the photographic print is formed of baryta, a water-resistant
coating material may be applied onto the outermost intermediate layer in order to
improve the stability against water and moisture.
[0012] It will thus be appreciated that the preferred embodiment of the invention provides
a photographic panel which affords a superior visual effect in the cases of both reflected
light and transmitted light.
1. A method of making a photographic panel, comprising making at least two photographic
prints of the same size from the same negative, applying adhesive to their surfaces
and onto one side of a separately provided transparent base, laminating said base
and a first one of said photographic prints so that the respective adhesive-applied
surfaces are in face-to-face relationship, thereby bonding the two together, then
removing the backing sheet of said one photographic print, laminating and bonding
the second of said photographic prints onto said first photographic print so that
their images are aligned, and then removing the backing sheet of said second photographic
print.
2. A method of making a photographic panel according to claim 1, wherein three or
more said photographic prints are laminated and bonded successively onto one side
of said base.