U.S. patent number 3,883,298 [Application Number 05/305,368] was granted by the patent office on 1975-05-13 for energy responsive thread.
Invention is credited to Gerald Platt.
United States Patent |
3,883,298 |
Platt |
May 13, 1975 |
ENERGY RESPONSIVE THREAD
Abstract
An energy responsive thread which develops color upon activation
by energy, especially electromagnetic energy, of a certain type or
energy level. A preferred embodiment comprises a photosensitive
thread which develops a permanent, specific color upon exposure to
electromagnetic radiation of a specific wavelength. The
photosensitive thread preferably contains photosensitive dyes which
develop a permanent, specific color, upon exposure to
electromagnetic radiation of a specific wavelength. Electromagnetic
radiation falling within the ultraviolet, visible and infrared
portions of the spectrum may be utilized. The thread may contain at
least three dyes which individually develop red, blue, and green
colors, The selective exposure of the individual colors provides
all the colors of the visible spectrum.
Inventors: |
Platt; Gerald (Salt Lake City,
UT) |
Family
ID: |
26974555 |
Appl.
No.: |
05/305,368 |
Filed: |
November 10, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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865917 |
Oct 13, 1969 |
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Current U.S.
Class: |
8/444; 8/494;
430/138; 112/475.01; 8/526 |
Current CPC
Class: |
D06P
5/20 (20130101); D02G 3/346 (20130101); G03C
1/7642 (20130101) |
Current International
Class: |
D02G
3/34 (20060101); D06P 5/20 (20060101); G03C
1/76 (20060101); D06p 005/00 () |
Field of
Search: |
;117/1.7 ;8/2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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380,208 |
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Sep 1932 |
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GB |
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674,642 |
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Jun 1952 |
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GB |
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309,166 |
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Jun 1930 |
|
GB |
|
Other References
Silk Journal and Rayon World, July 1945, pages 32 &
42..
|
Primary Examiner: Levy; Donald
Attorney, Agent or Firm: Trask & Britt
Parent Case Text
This is a continuation of application, Ser. No. 865,917 filed Oct.
13, 1969, now abandoned.
Claims
I claim:
1. A method of sewing a colored fabric comprising
a. stitching said fabric with a thread having three light sensitive
dyes which develop a specific, permanent color upon exposure to
light, and
b. exposing said thread to light to develop a color matching that
of the fabric in the immediate vicinity of said thread.
2. The method of claim 1 wherein said light sensitive dyes develop
colors of red, green and blue upon exposure to light of the visible
spectrum.
3. The method of claim 1 wherein at least one of said dyes is
protected by a light filter.
4. The method of claim 1 wherein a silver halide is present with
said dyes.
5. The method of claim 1 wherein said dyes are separately contained
in microspheres adhered to said thread.
6. The method of claim 2 wherein said thread after exposure is
treated with a developer.
7. The method of claim 6 wherein said developed thread is treated
with a fixing solution.
Description
BACKGROUND OF THE INVENTION
In the manufacture of articles from textiles it is common
commercial practice to sew various parts of fabric together to form
a finished article. Clothing, draperies, tablecloths, furniture
coverings and the like are frequently made of separate parts of
fabric and joined at seams by threads sewn into the fabric.
Frequently, the fabric has a color and often times a design of a
multitude of colors. If fabric is a single color, a thread matching
that color is preferably used to join the parts together. If the
fabric is a multi-colored article then a thread having a more or
less neutral color is chosen. Nonetheless, the thread is very
evident in multi-colored fabrics. It is an object of this invention
to provide a thread which color-harmonizes with the surrounding
fabric. It is an objective to provide a thread which is essentially
colorless and which can be sewn into a multi-colored fabric and
which will develop permanent, specific colors which harmonize with
the color of the fabric in the immediate vicinity of the
thread.
INVENTION
A novel energy responsive thread and method of sewing fabrics has
now been invented. The thread contains energy responsive dyes which
develop a specific, permanent color upon activation. The thread can
be used to sew fabrics whereby the thread, upon activation before
or after entering the fabric, develops a color to match the color
of the fabric in the immediate vicinity of the thread. The thread
upon proper activation, has the potential of developing all the
colors of the visible spectrum.
The energy utilized to activate the novel thread of this invention
may be thermal or electromagnetic. The use of electromagnetic
energy, especially of a wavelength falling within the visible
spectrum, is preferred in this invention. In describing novel
threads which are responsive to electromagnetic radiation the term
"photosensitive" is frequently used.
A novel photosensitive thread has now been invented which develops
a permanent, specific color upon exposure to electromagnetic
radiation of the specific wavelength. The invention is especially
useful inasmuch as multi-colored fabrics may now be sewn with a
single thread and the color of the thread developed to match the
color of the fabric in the immediate vicinity of the thread. Thus,
the novel photosensitive thread of this invention has the ability
to develop any or all of the colors of the visible spectrum.
Ordinary threads of cotton, nylon, saturated polyesters, cellulose
acetate, rayon, and the like may be treated so that the resulting
thread or filament is energy responsive and will develop a specific
color in response to certain stimuli.
The invention can utilize energy responsive dyes, especially dyes
which develop specific colors upon exposure to electromagnetic
radiation of a specified wavelength. In one embodiment of this
invention the thread contains at least three dyes which
individually can develop red, blue, and green colors. By selective
development of the individual colors of each of these dyes all the
colors of the visible spectrum may be obtained. The dyes may be
directly or indirectly attached to the threads and may be
chemically or physically associated with the filament.
Further description of the instant invention may be facilitated by
reference to the following drawings:
FIG. 1 is a cross sectional view of a filament having microspheres
containing color-developable dyes attached;
FIg. 2 is an enlarged view of a cross section of a
color-developable microsphere;
FIG. 3 shows an enlarged view of a twisted thread composed of three
filaments each having a potentially different color;
FIG. 4 is a perspective view of a fabric being sewn with a
photo-sensitive thread;
FIG. 5 is a perspective view of a fabric being sewn with a
photo-sensitive thread.
FIG. 1 is a cross-sectional elevational view of a thread or
filament 1 with a mono-layer of microspheres adhered thereto. These
microspheres are very small, having a diameter on the order of
about 0.01 inches to less than about 0.0005 inches. The
microspheres contain chemical compounds which have a potential of
becoming dyes or colorants. Microsphere 2 has the potential of
becoming blue in color if properly activated. Microsphere 3 has a
potential of becoming red in color while microsphere 4 has a
potential of becoming green in color. Because these spheres are so
small and packed together, it is possible to simulate any color
found in the visible spectrum by selective activation of the
individual colors. For example, if only the red and green spheres
are activated the resulting confusion light emanating from the
surface of the tightly packed spheres will cause the surface to
appear yellow in color.
These spheres may be adhered to the filament by any appropriate
binder. Starch type binders, for example, wheat flour, and the
like, may be utilized in a water suspension to adhere the spheres
to the filament. It is preferred, however, that the binder be water
insoluble. Many resinous materials such as varnishes, shelacs and
the like may be utilized as binders.
FIG. 2 illustrates an individual sphere. The interior portion 6
contains a chemical compound which is capable of becoming a dye or
colorant under certain conditions. The chemical compound may be
disbursed in a gelatin or similar gelatinous material or may exist
in liquid form encapsulated within an outer shell 5. Even if the
center portion 6 is self-supporting, frequently an outer shell 5 is
included and contains a light filter or other material which
screens out undesired stimuli. In this manner the microsphere may
be rendered activatable only by a specific type of stimuli. For
example, a silver halide emulsion sensitized to be responsive to
green light as well as blue light may contain a yellow filter to
filter out the blue light, thus allowing the sphere to be sensitive
only to green light. Since the screening layer may contain a dye
which contributes color to the system, it is frequently preferred
that the screening layer or shell 5 be water soluble and capable of
easy removal.
FIG. 3 is an enlarged view of a thread composed of twisted
filaments, each filament having a different color. Since each
filament is developable to one of the three basic colors, any color
contained in the visible spectrum may be obtained by proper
activation and development. These filaments may contain
microspheres on the surface, such as the filament in FIG. 1 or the
filaments may be saturated with the appropriate chemical compound
and overcoated in the proper manner to protect against evaporation
or undesired activation. The potential colorant or dye may, of
course, be dispersed in a coating material such as gelatin and
applied as a coating on the filament.
FIG. 4 is a prospective view of an apparatus which may be used with
the photosensitive thread. Fabric 10 passes under a sewing machine
head 11 through which the photosensitive filament is threaded. The
photosensitive thread is protected from light until it is threaded
into the needle 12 and sewn into the fabric. A white light 13 is
placed below the fabric and shines through the fabric thus exposing
the thread 21 to the colors of the fabric in the immediate vicinity
of the thread. After the thread is exposed it passes into a
development zone 5 where the color is photodeveloped to match the
color of the surrounding fabric. After developing the color of the
thread, the fabric passes into a fixing zone 14 wherein the color
of the thread is fixed, that is, rendered inactive to subsequent
exposure to light. The developing of the thread may be either a wet
or dry process depending upon the chemical characteristics of the
photosensitive filament. The same is true of the fixing
process.
FIG. 5 is a schematic representation of another apparatus and
method for sewing fabric with a photosensitive thread 21 to match
the colors of the fabric. A light and color meter 16 reads the
intensity and color of the fabric at a pre-determined point. This
information is conveyed to a control mechanism 17 which directs the
color and intensity of light emanating from the lamp 18. The lamp
18 exposes thread 21 at a predetermined point to the same colors
and intensity of light read from the fabric by meter 16. A portion
of the fabric and the portion of the thread exposed are in a fixed
relationship so that the exposed thread will enter that portion of
the fabric which the thread matches in color. After the thread 21
is exposed it proceeds into a developing chamber 19 and then into a
fixing chamber 20. In this apparatus the color of the thread is
developed and fixed to match a particular portion of the fabric
before it is sewn by a machine needle 12 into the fabric.
In its broad aspects, this invention embodies an energy-responsive
thread which develops a permanent specific color. Such a thread is
especially useful for sewing together colored fabrics wherein the
color of the thread is developed to match that of the fabric. The
thread in its undeveloped state preferably has a potential of being
developed to match any color of the visible spectrum. The thread
may be exposed and color-developed prior to the time it enters the
fabric or the thread may be exposed and developed after it enters
the fabric.
Photosensitive threads are one type of energy-responsive threads
which are especially useful inasmuch as a minimum of translation is
necessary between the color sensing device and the exposure device.
FIG. 4, above, illustrates a device wherein the photosensitive
thread is exposed to light possessing the wavelength of the color
which the thread is to match. There is no translation of different
types of energy in this system. The thread is subsequently
developed and the color fixed.
A photosensitive thread of the type illustrated in FIG. 1 may be
fabricated by adhering minute, discrete, spheres, which are capable
of developing the three basic colors; blue, green, and red or their
counterparts, yellow, cyan, and magenta. These spheres can contain
dyes which develop a permanent, specific color upon activation. A
direct way of activating the dye comprises using light of the
wavelength of the color desired. The dyes utilized may be
photosensitive or may be oxidizable to yield the desired color. The
oxidizable dyes may be used in conjunction with silver halide
wherein the oxidizing condition is created during the reduction of
the silver halide to metallic silver by the action of light.
Silver halide emulsion for photographic films are well known.
Silver halide systems, however, are sensitive only to blue light
(400-500 millimicrons). To render silver halide system sensitive to
green light (500-600 millimicrons) and red light (600-700
millimicrons) it is necessary to use a sensitizing agent. The
preparation of photographic grade emulsions containing silver
halides, for example, silver bromide, and the sensitization of said
emulsions to render them sensitive to green and red light is well
known in the photographic art. Three separate emulsions may be
prepared, one sensitive only to blue light, another sensitive only
to green light, and a third sensitive only to red light. Since
silver halides are naturally sensitive to ultra-violet and blue
light, emulsions sensitive only to green or red light must be
protected from the blue and ultra-violet radiation. This can be
accomplished by utilizing a light filter which filters the blue and
ultra-violet. To each of the emulsions is added a pre-cursor of a
dye of the color to which that emulsion is sensitive. For example,
to the emulsion sensitive to blue light is added a pre-cursor which
forms a blue dye in combination with the developer in the presence
of activated silver halide. Thus, if the blue sensitized emulsion
has been exposed to light containing electromagnetic radiation in
the blue region of the spectrum, the silver halide present will be
activated and upon development will be reduced to metallic silver.
The dye pre-cursor and developer form a blue dye under the
oxidizing conditions present.
Microspheres of the gelatin photographic emulsion may be formed in
diameters of about 0.005 inches or less to a diameter of about 0.01
inches. Microspheres of blue, green, and red sensitized
photographic emulsions developable to the color of sensitization
could be randomly adhered to a thread or filament. One method of
adhering microspheres to filaments comprises passing a tacky
filament through an agitated or a fluidized bed of a mixture of the
microspheres. The resulting thread with microspheres attached would
have the appearance shown in enlarged form in FIG. 1 although the
spheres would not necessarily be limited to a single layer. The
thread would then be packaged in a light-protected enclosure and
utilized in a sewing machine in the manner shown in FIGS. 4 or 5.
The thread could be developed to its proper color either before or
after it is sewn into the fabric.
Upon exposure to light silver halide becomes activated. For
example, if the light to which the filament is exposed contains
only green light then the spheres sensitive to green light will be
the only ones in which the silver halide is activated. The
activated silver halide, e.g., silver bromide, can then be reduced
to metallic silver upon contact with developer solution. The
solution can also interact with the dye pre-cursor to form a dye in
those spheres in which the silver halide has been activated. For
example, if the spheres sensitive to green light are the only ones
in which silver halide has been activated, then the interaction of
developer with the pre-cursor or coupler, as it is frequently
called, results in a green dye. For example, if the green
sensitized microsphere contains pentochloro-alpha-nuphthor as the
coupler and is contacted with ethyl-paraphenylene diamine as the
developer, a green dye will be formed if activated silver halide is
present and reduced to metallic silver by the developer.
After development, the thread and fabric to which it is sewn are
treated with a fixing solution so that subsequent exposure to light
will not activate any of the silver halide present. In this manner
the desired color obtained during the controlled exposure will be
the only color developed by the photosensitive thread. During
fixation it is generally desired to rinse the thread and the
material first preferably with a water solution containing a mild
acid such as acetic acid, diglycolic acid or the like, to
neutralize any developer present. The photographic material can
then be treated with a fixing agent such as a thiasulfate to react
with the silver halide present to obtain a stable silver compound.
A developing and fixing stage may be accomplished in one step
utilizing known techniques.
Photosensitive threads may be constructed without the use of a
silver halide. U.S. Pat. No. 3,445,234 discloses image forming
compositions which form colored dyes in response to activation by
ultra-violet light. A solution of bis-(4-diethyl
amino-o-toluyl-methane-tri-hydrochloride with an equal weight of
2,2'-bix(o-chlorophenyl)-4,4', 5,5'-tetraphenylbiimidazole in equal
parts by volume of benzene in NN-diethyl formamide could be
utilized to impregnate a microsphere of gelatin or other carrier.
When exposed to ultraviolet light a blue coloring appears. Thus, if
such a microsphere were sensitive only to a certain wavelength of
ultraviolet light, the microsphere could be activated in a system
such as that shown in FIG. 5 wherein the color of the fabric is
read and the information communicated to an energy source. If blue
is one of the colors appearing in the fabric then the energy source
or exposure light would be controlled to emit the wave-length of
ultraviolet light which would activate the sphere having the
potential of developing a blue color.
Compositions are disclosed in U.S. Pat. No. 3,445,234 which develop
a green color upon exposure to ultraviolet light and which develop
a red color upon exposure to ultraviolet light. By using the proper
screening agents a microsphere having the potential of developing a
red color could be rendered sensitive only to ultraviolet light in
the range of 300 to 400 millimicrons. Similarly, a system having
the potential of developing a green color could be sensitive only
to wavelengths of 200 to 300 millimicrons while a blue system could
be rendered activatable only by ultraviolet lights of 100 to 200
millimicrons. Thus, by using the systems in conjunction with a
system disclosed in FIG. 5 a red color can be obtained where a red
color is detected in the fabric.
Once the desired color is achieved through exposure and
development, the color may be fixed by the addition of hydroquinone
or other deactivator to the system.
A similar non-silver system can be obtained using the compounds
disclosed in U.S. Pat. No. 3,445,232 wherein microspheres may be
obtained in the manner disclosed above.
EXAMPLE I
Three separate batches of gelatin spheres impregnated with
photosensitive silver chloride emulsions are prepared. A
sensitizing agent responsive to green light (500-600 mu) is
included in one emulsion while another emulsion is sensitized in
the 600-700 mu (red) region. The remaining emulsion contains no
sensitizer and is, therefore, sensitive only to blue light (400-500
mu). Silver chloride emulsion's are sensitive only to UV light and
blue light unless separately sensitized.
A photographic grade emulsion is prepared by suspending silver
chloride or, preferably, silver bromide, in a solution of
gelatin.
An alternative method of preparing a photographic grade emulsion
comprises the addition of an alcoholic metal halide, such as
potassium bromide, to gelatin containing silver nitrate. If this
method is used, it is preferred to wash the alkali metal nitrate
from the gelled colloid. Microspheres of the gelatin are formed as
the emulsion is cooled. Typically, the sphere is about 10% to 50%
by weight of silver halide, although preferably the silver halide
concentration is about 20% to 40%. The concentration used in this
example is about 25%. The microspheres may be formed by slowly
feeding warm silver halide containing gelatin into one end of a
small, hollow rotating tube and cooling the gelatin as it passes
the length of the tube.
The microspheres are conventionally less than about 0.01 inches in
diameter although best results are achieved when the sphere
diameter is less than about 0.005 inches and preferably less than
about 0.001 inches. Spheres of 0.0005 inches and less are
especially useful in conjunction with fine filaments.
The microspheres may be formed by atomization, prilling and similar
techniques.
Other protective colloids which may be substituted for gelatin
include agar agar, albumen, caesin, collodion, cellulose esters and
the like.
Microspheres sensitive to red light (600-700 mu) are prepared by
including a blue dye in the formulation. This may be accomplished
by adding the dye to the photographic-type emulsion or by
absorption of the dye by the microspheres. The dye is included as
about 0.1 to 10.0% by weight of the weight of the total system.
Dyes which sensitize silver halides to red light include pinacyanol
or 1,1'-diethyl-2,2'carbocyanine chloride, dicyanine or
1,1'-diethyl-2,4'-carbocyanine chloride,
3,3'-diethyl-4,5,4'5'-dibenzothiacarbocyanine bromide,
3,3'-dimethyl-9-phenyl-4,5,4'5'-dibenzothiacarbocyanine chloride,
3-ethyl-5- 4-(3-ethyl-2-benzothiazolinylidine)-2-butenylidene
rhodanine,
3-ethyl-5-4-(3-methyl-2-benzothiazolinylidine)-1,3-neopentylene-2-
butenylidene rhodanine and the like. Other dyes known to sensitize
silver halides in the red region of the visible spectrum may also
be utilized. These dyes are included, preferably, in concentrations
which do not substantially contribute any color to the sphere.
To the spheres sensitized to light wavelengths of 600-700 mu, a
coupling agent is added which reacts with developer under oxidizing
conditions to form a red dye. Sufficient quantity of the coupling
agent should be added so that substantial color is contributed if a
substantial quantity of silver halide is activated by light of
600-700 mu. The activation of silver halide and its subsequent
reduction of metallic silver provides oxidizing conditions.
Suitable couplers and developers to obtain red dyes include:
coupler developer ______________________________________
phenyl-cyan-methylacetone diethyl-p-phenylenediamine
N-phenylhomophthalimide 4-amino-3-methyl-N,N- diethylaniline
______________________________________
The quantity of coupler included in the emulsion can be as great as
the system will tolerate. The minimum quantity should be the least
quantity which will contribute color upon activation and
development of silver halide. Ordinarily, the coupler should be
included as approximately 10% to about 100% of the molar
concentration of the silver halide. In this example the coupler
molar concentration is 50% of the silver chloride
concentration.
Microspheres sensitive to green light (500-600 mu) are prepared by
including a dye such as corallin, erythrosin,
1,1'-diethyl-2,4'-cyanine iodide (ethyl red),
1,1'-diethyl-6,6'-dimethyl-2,4'-cyanine bromide (orthochrome T),
1,1'-diethyl-6,6'-diethoxy-2,4'-cyanine bromide (pinadirome), and
1,1'-diethyl-2,2'-cyanine iodide. Other dyes known to sensitize
silver halides in the green region of the visible spectrum may also
be utilized. The dye is added at about 0.1% to about 10% by weight
of the total system. The sensitizing dye is preferably added in
concentrations which do not substantially contribute any color to
the sphere.
To the spheres sensitized to light wavelengths of 500-600 mu, a
coupling agent is added which reacts with developer under oxidizing
conditions to form a green dye. Sufficient quantity of the coupling
agent should be added so that substantial color is contributed if a
substantial quantity of silver halide is activated by light of
500-600 mu.
Suitable couplers and developers to obtain green dyes include:
coupler developer ______________________________________
pentachloro-.alpha.-naphthol diethyl-p-phenylene diamine
pyrimidazolone 4-amino-3-methyl-N,N-diethylamiline
______________________________________
The quantity of coupler included in the green light sensitized
spheres is within the same range of concentrations set forth for
the red light sensitized spheres.
The red and green sensitized microspheres are coated with a thin
layer of gelatin containing a yellow dye to prevent blue light from
passing into these spheres. The yellow dye is water soluble and
easily removable from the surface of the microspheres.
Microspheres sensitive to blue light (400-500 mu) are prepared
without addition of sensitizers inasmuch as silver halides are
naturally sensitive to blue and ultraviolet light. A coupling agent
is added which forms a blue dye upon reaction with developer under
oxidizing conditions. It is added to the microspheres sensitive
only to blue light.
Suitable couplers and developing agents include:
coupler developer ______________________________________
.alpha.-naphthol diethyl-p-phenylene diamine C.sub.6 H.sub.5
COCH.sub.2 CONH C.sub.6 H.sub.5 4-amino-3-methyl-N,N-diethylaniline
______________________________________
The quantity of coupler included in the spheres sensitive to blue
light is within the range of concentrations set forth for the red
light sensitized spheres.
Equal quantities of spheres sensitive to red, green, and blue light
are placed in a container having a light weight cotton thread
passing upwards through an orifice at the bottom. The thread is
coated with a wet starch binder. Other binders, of course, could be
used. Resinous binders such as lacquers, varnishes, etc. are
preferably utilized when water resistance is desired.
The spheres are randomly placed in the container. Mile agitation or
mild fluidization can be utilized to maintain the microspheres in a
loose, random orientation.
As the sticky thread passes upwards through the container,
microspheres adhere thereto in a random fashion. The microspheres
form essentially a monolayer on the surface of the thread.
The thread is allowed to dry before use.
The above operations are conducted in the absence of visible or UV
light so that the silver halide is not activated.
The dried thread is wound into an enclosed container where it
continues to be sealed from light.
The thread is then placed in an apparatus of the type set forth in
FIG. 4 where it is sewn into a multi-colored fabric with a light
source sufficient to expose the thread located below the fabric.
After exposure the thread and fabric is developed by treatment with
a developer as set forth above. The time required for development
may vary from a few seconds to several minutes. The speed of
development increases with increased temperature. Temperatures
above room temperature are preferred in hastening development.
Temperatures of about 100.degree. F. to 200.degree. F. may be used
to maintain a development time of less than 1 minute.
After development the color is fixed by immersion or washing with a
typical sodium thiosulfate solution used in the photographic
industry. A small quantity of an organic acid is preferably
included in the aqueous fixing solution in accord with known
practices in the photographic industry. The time of fixing may be
accelerated by increased temperatures, for example, above
60.degree. F the fixing time may be reduced substantially below 1
minute.
The thread which has been so treated matches in color the fabric
into which it had been sewn.
Although the above example sets forth the preferred mode of
practicing this invention, the invention is not limited to silver
systems or the methods described therein.
As set forth above, non-silver photographic systems known to the
art may be utilized. These systems are susceptible of being
activatable by specific stimuli, for example, specific wavelengths
of electromagnetic radiation, to develop a certain desired color.
Known light filters may be utilized to exclude unwanted wavelengths
of light from an activatable system.
Although the coating of a filament with microspheres containing
activatable systems is a presently preferred construction, numerous
other structures may be utilized. The dyes or activatable compounds
may be applied in layers to a filament in a manner similar to that
used in constructing color film in the photographic art. Also, as
shown in FIG. 3, three filaments may be interwound in a fashion
wherein each develops a primary color. In this embodiment the
filaments may be saturated with the dye and overcoated with gelatin
or comparable coating material.
The invention utilizes the techniques of color photography wherein
any color of the spectrum is created by proper development of the
primary colors, red, green, or blue. Other basic color systems
would be used, for example, where cyan, magenta or yellow, are the
three colors, similar to the substractive color method of color
photography. The positive primary colors, green, red and blue, are
preferred for use in this invention.
The light filters suggested above for screening-out unwanted colors
are well known in the photographic film art. These known light
filters for photographic films may be utilized in this
invention.
The resinous binders useful for adhering microspheres to threads in
this invention are preferably colorless as well as water insoluble.
Known binders and adhesives may be utilized for this purpose.
The state of the art in color photography is represented by the
following texts: C. E. K. Mees and T. H. James, The Theory of the
Photographic Process, The Macmillan Co., (1966) and Neblette,
Photography, Its Principles and Practice, 4th edition Van Nostrand
Co. (1946).
Although the invention has been described above with reference to
specific embodiments, it is not intended that the invention be
limited solely thereto but to include all the modifications and
variations falling within the scope of the appended claims.
* * * * *