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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of maintaining the development
activity of a photographic lithographic developer employed in an automatic
developing machine constant and, more particularly, it is concerned with
an improvement in a method of maintaining the development activity
constant by using two kinds of replenishers differing in free sulfite ion
concentrations, bromide ion concentrations and pH.
2. Description of the Prior Art
When photographic processings are carried out on an industrial scale, it
becomes necessary to control various development process conditions, for
instance, temperature, time, agitation, developer, development activity,
etc., used.
In order to control development activity, a supplemental amount of a
developer has been added to a developer solution being used for every
photosensitive material processed so as to maintain the development
activity constant. This method is, in general, called "replenishment" in
the photographic art. Therefore, the present invention relates to a method
of replenishing a photographic lithographic developer.
The activity of the developer decreases principally due to the following
factors:
(a) Development reactions taking place at the time of the
development-processing of films (which will be described hereinafter as
"processing exhaustion" for brevity) affect the developer activity.
Namely, development of films causes various chemical effects to occur in
the developer used. Examples of such effects include a decrease in the
concentration of the developer, an increase in the concentration of the
oxidation products of the developing agent accompanying the
above-described decrease in developer concentration, and the liberation of
halide ions from the silver halide present in the developed films into the
developer used.
(b) Natural deterioration occurs in the developer stored in a tray or a
tank, and aerial oxidation of the developer occurs spontaneously by
reaction with oxygen in the air (which will be described hereinafter as
"time-passage exhaustion" for brevity).
When development-processing using an automatic developing machine is
allowed to continue for a long time of several days to several months,
both factors (a) and (b) above take place causing a decrease in the
development activity of the developer used.
Since each of these two factors influences the developer in individual and
different ways, an assumption regarding the relative extents of the
influence exerted by the two factors described above on the developer must
be made so that the composition of replenisher to be added can be
determined.
Where a number of films are development-processed successively on a regular
basis during the twenty-four hours of every day using an automatic
developing machine which is operated continuously, a supplemental amount
of the developer is added for every processing depending on the quantity
consumed by the previous processing. That is to say, since the rate of
consumption of the developer can be regarded as approximately constant on
such an occasion, satisfactory results can be achieved by addition of
replenisher to compensate for processing exhaustion for the processing of
each film in the amount necessary to replenish for the consumption of the
developer occurring in the processing of each film.
However, in operation, an automatic developing machine is not used
continuously, for example, the processing of films is stopped at night or
over the weekend. Therefore, the factor (b) described above also
influences the developer used. Such being the case, if only a replenisher
to compensate for process exhaustion is added, the development activity of
the developer cannot be maintained constant.
In photographic development-processing which has been predominantly carried
out in the past, the quantity of the replenisher to compensate for process
exhaustion to be added has been determined on the basis of the amount of
developed silver halide present in the developed film, which depends upon,
for example, the size of the film developed, the blackened area of the
film developed, the kind of film developed and the characteristic of the
developed image (e.g., whether the image is positive or negative).
The photographic speed of the developer to be used should be evaluated
before processing by measuring the blackened density which is obtained by
developing a control film strip having a latent image therein due to a
prior exposure to light with an exact exposure, with the developer. The
quantity of replenisher to be added can be adjusted on the basis of the
change in the density of the developed image formed on the control film
strip. When the blackened density of the control film strip obtained is
lower than the initial value, replenisher should be added to the
developer.
In addition, replenishment to compensate for the decrease in the
development activity occurring in the developer resulting from the passage
of time has been conventionally carried out by adding a replenisher having
a composition similar to or different from that of the replenisher used to
compensate for process exhaustion in an amount determined by the blackened
density of a control film strip in a similar manner to the case of
deterioration caused by the development-processing. Using this approach,
however, only the photographic speed of the developer can be restored to
the initial level.
In the replenishing method to compensate for deterioration due to the
passage of time as described above, the amount to be supplemented has been
determined by trial and error. Therefore, the determination of the optimum
amount to be supplemented requires a lot of work and a long period of time
and, further, there is a great concern that photographic characteristics
such as the quality of the dots and the half-tone gradation related to the
tone reproduction of the original image cannot be restored completely to
the level obtained using a fresh developer, even though the sensitivity
can be restored to the initial level by the addition of replenishers. More
specifically, it is impossible to restore the development activity
accurately to the level obtained using a fresh developer in accordance
with the replenishing method described above.
Moreover, an automatic replenishing system for the developer is disclosed
in Japanese Patent Application (OPI) No. 5436/1971 (corresponding to
British Patent No. 1,313,796), wherein the content of halides present in
the developer and the concentration of the developer are monitored and the
information obtained thereby is analyzed, followed by the appropriate use
of two kinds of replenishers in which the concentrations of halide ions in
each corresponds to the requirements obtained from the analysis. In this
replenishment system, two kinds of solutions having different halide ion
concentrations are employed. One contains a low concentration of halide
ions. The other contains a high concentration of halide ions; that is to
say, almost the same concentration as that desired in the developer. The
replenisher with a lower concentration of halide ion may be added in a
conventional manner, namely, depending on the amount of films passed
through the developer. The other replenisher having a higher concentration
of halide ion may be added when restoration of the development activity
lost by aerial oxidation is essential, but the concentration of halide ion
must be maintained as it is without change, which occurs sometime after
the use of the developer. However, such an automatic replenishing system
possesses serious disadvantages that the apparatus employed as the monitor
is, in general, very expensive and the maintenance of the apparatus
requires much time and labor.
Methods for replenishment by adding replenishers to compensate for process
exhaustion and to compensate for time-passage exhaustion where the
components of the replenishers are different are disclosed in German
Patent Application (OLS) No. 2,004,893 and in U.S. Pat. No. 4,025,344.
However, in each of these methods, the disclosure is of the addition of
replenishers where the components of the replenisher to compensate for
exhaustion due to processing and the components of the replenisher to
compensate for exhaustion due to ageing, which occurs during operation of
the automatic developer machine, are different. No considerations are
taken in these methods for the time-passage exhaustion which also occurs
when the automatic developing machine is turned off and operation is
suspended.
Where the suspension time is short, i.e., the automatic developing machine
is turned off for a short period of time, the time-passage exhaustion
which occurs during the suspension of the automatic developing machine can
be neglected. However, where the suspension time continues for a long
period of time, the time-passage exhaustion during the suspension must be
considered. Especially, when the developer used is a lithographic
developer, processing in a stable manner would not be achieved, if one
neglects the time-passage exhaustion which occurs during the time of
suspension, when the automatic developing machine is turned off and not
operated.
Since the change in the composition of the developer due to ageing mainly
comprises a decrease in free sulfite ion concentration, therefore, this
change in developer composition does not cause a change to occur in visual
sensitivity. However, with lithographic development, the dot quality is
affected greatly by the decrease in free sulfite ion concentration and if
exhaustion due to ageing which occurs during suspension of operation is
neglected, it is impossible to maintain the true development activity of
the developer constant.
The true development activity can be only maintained constant when
compensation for the time-passage exhaustion of the developer,
particularly a lithographic developer, which occurs during a suspension of
the automatic developing machine is made.
SUMMARY OF THE INVENTION
Accordingly, a first object of the present invention is to provide a
practical method for replenishing a developer so that the activity of a
developer may be maintained constant under any conditions concerning the
quantity of films already treated, wherein various defects as described
above in the prior art replenishing processes to compensate for
time-passage exhaustion occurring in the developer by processing of films
can be eliminated.
A second object of the present invention is to provide a simple
replenishing method for a developer to compensate for time-passage
exhaustion occurring in the developer, which does not require the use of
personnel having a large amount of experience.
A further object of the present invention is to provide a simple and
practical replenishing method for a lithographic developer wherein the
exhaustion due to the passage of time occurring in a so-called infectious
developer, which is employed for the development of lithographic silver
halide photographic materials, can be compensated for and the true
development activity thereof can be always maintained constant by adding a
replenisher appropriate to compensate for exhaustion due to the passage of
time, which has a composition different from that of the replenisher
appropriate to compensate for exhaustion due to the
development-processing, in a simple and practical manner.
The above-described objects are attained by a method for automatically
processing silver halide lithographic photosensitive materials with a
lighographic developer using an automatic developing machine, wherein the
improvement comprises maintaining constant the development activity of the
lithographic developer by adding supplemental amounts of two kinds of
replenishers to the developer, a replenisher (RD) being employed to
compensate for the decrease in the development activity resulting from the
development-processing of the lithographic photosensitive materials and a
replenisher (RO) being employed to compensate for the decrease in the
development activity resulting from the passage of time, where
replenishers (RD) and (RO) deffer in free sulfite ion concentrations,
bromide ion concentrations and pH, wherein the method comprises adding
replenisher (RD) during the development-processing operation in a
supplemental amount in proportion to the size of the film processed, the
degree of exposure of the film processed and the percentage of the exposed
area of the film processed and, prior to the start of each
development-processing operation, adding replenisher (RO) in a
supplemental amount previously determined (a) depending upon (i) the time
interval from the suspension of the development processing operation of
the automatic developing machine when last operated to the start of the
development-processing operation of the automatic developing machine and
(ii) the temperature at which the lithographic developer was kept during
the time interval (i), where replenisher (RO) was added during the
previous development-processing operation of the automatic developing
machine, or (b) depending upon (i') the time interval from the start of
the development-processing operation of the automatic developing machine
when last operated to the start of the development processing operation of
the automatic developing machine and (ii') the temperature at which the
lithographic developer was kept during the time interval (i'), where no
replenisher (RO) was added during the previous development-processing
operation of the automatic developing machine.
BRIEF DESCRIPTIONS OF THE DRAWINGS
FIG. 1 and FIG. 2 illustrate graphically the relationship between the
decrease in the development activity and the time interval of suspension
of the development opration, and the relationship between the decrease in
the development activity and the temperature at which the developer was
kept during the time interval of suspension of the development operation,
respectively.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is utilized for silver halide lithographic
photosensitive materials, e.g., for making photolithographic plates
(hereinafter called "litho-films") which are development-processed using a
so-called infectious developer (hereinafter called a "litho-developer" and
often herein simply "developer") and an automatic developing machine.
Therefore, the detailed descriptions appearing hereinafter is with respect
to litho-films and litho-developers. Since a litho-developer has an
exceedingly high tendency toward aerial oxidation with the passage of
time, maintaining the development activity of a ligho-developer constant
by restoring the development activity decreased by exhaustion due to the
passage of time, mostly caused by aerial oxidation, to the initial level
is important.
A litho-developer is an aqueous alkaline processing solution containing
principally a dihydroxybenzene type developing agent and a sulfite and,
further, containing free sulfite ions.
Suitable litho-developing agents which can be used in a litho-developer can
be appropriately chosen from dihydroxybenzenes, which are well known in
the photographic art. Specific examples of dihydroxybenzenes which can be
used include hydroquinone, chlorohydroquinone, bromohydroquinone,
isopropylhydroquinone, toluhydroquinone, methylhydroquinone,
2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone and other
p-dihydroxybenzenes. Of these, hydroquinone is particularly preferred.
These developing agents may be used individually or as combinations
thereof. The developing agent is employed in an amount of about 5 to about
50 g, and preferably, 10 to 30 g, per liter of the developer. The
developer must be alkaline when used, as is well known in the photographic
art. Therefore, the pH of the developer is adjusted to a pH of higher than
about 8 and, preferably, from 9 to 11. The kind and the amount of alkali
agent to be used are not particularly restricted.
Examples of sulfites which can be employed to prepare a litho-developer
containing a high concentration of free sulfite ions include sodium
sulfite, potassium sulfite, potassium metabisulfite and other alkali metal
bisulfites commonly used in the photographic art.
Although the free sulfite ion concentration of the developer is not
particularly limited, a concentration of not more than about 6 g per liter
of the developer is preferred.
The litho-developer can contain additional components as set forth below,
in addition to the above-described components. These components can be
incorporated into a litho-developer during the preparation thereof, after
the preparation thereof but prior to use or during the
development-processing.
One additional component is a sulfite ion buffer which is added to the
litho-developer in such an amount that a constant sulfite ion
concentration is achieved. Specific examples of sulfite ion buffers which
can be used include aldehyde-alkali metal bisulfite addition products such
as a formaldehyde-sodium bisulfite addition product, ketone-alkali metal
bisulfite addition products such as an acetone-sodium bisulfite addition
product, carbonyl bisulfite-amine condensation products such as sodium
bis(2-hydroxyethyl)aminomethane sulfonate and so on. The amount of the
sulfite ion buffer employed can range from 0 to about 130 g, preferably,
30 to 60 g, per liter of the developer.
The litho-developer can also contain water soluble acids (e.g., acetic acid
and boric acid), water soluble alkalis (e.g., sodium carbonate and sodium
hydroxide), pH buffers such as salts (e.g., sodium carbonate), and a
development controlling agent such as an alkali metal halide (e.g.,
potassium bromide). Certain alkalis can not only render the
litho-developer alkaline but also act as a pH buffer agent and a
development controlling agent. Furthermore, the litho-developer can also
contain an antioxidant such as ascorbic acid, or primary or secondary
alkanolamines (e.g., diethanolamine); an organic anti-foggant such as
benzotriazole, 1-phenyl-5-mercaptotetrazole, etc.; a water softener such
as ethylenediaminetetraacetic acid, nitrilotriacetic acid, etc.;
polyalkylene oxides; amine compounds; and organic solvents such as
triethylene glycol, dimethylformamide, methyl alcohol, Cellosolve or the
like, each in conventionally used amounts.
Of the above-described components for a litho-developer, in the present
invention it is only necessary for the essential components to be present
at the time of development, and any form can be used. For instance, each
of components can be separately dissolved in an appropriate solvent prior
to use and they are then mixed at the time of development, or all
components can be previously mixed together in the form of a powder or a
solution thereof. Also, a mixed solution of the components may be stored
as a concentrate or mixed solutions each containing some of the components
may be stored as concentrates and combined on use.
The compounded chemicals are optionally dissolved into or diluted with
water upon the use thereof.
Typical examples of litho-developers are disclosed in, for instance, U.S.
Pat. Nos. 3,622,330, 3,325,286, 3,158,483, 3,142,568 and 3,030,209.
In case of development-processing of litho-films using a litho-developer as
described above and an automatic developing machine, in the present
invention, the development activity of the litho-developer is maintained
constant by adding a supplemental amount of the replenisher (RD) to
compensate for process exhaustion, which results in a decrease in the
development activity caused by the development processing of litho-films
(hereinafter"process exhaustion replenisher (RD)"), and on the other hand,
by adding a supplemental amount of the replenisher (RO) to compensate for
time-passage exhaustion, which results in a decrease in the development
activity caused by the passage of time (mainly due to aerial oxidation)
(hereinafter "time-passage exhaustion replenisher (RO)"), wherein these
two kinds of replenishers (RD) and (RO) differ in sulfite ion
concentrations, bromide ion concentrations and pH.
The replenisher compositions contain substantially the same components as
those present in the litho-developer described above. However, different
concentrations of some or all of the components are used. Important
components in the replenisher compositions are (1) a developing agent
(e.g., hydroquinone), (2) a bromide (e.g., potassium bromide, sodium
bromide or the like) and (3) free sulfite ions. In addition, (4) the pH is
an important factor in the replenishers.
In the present invention, the process exhaustion replenisher, replenisher
(RD), contains (1) a higher concentration of the developing agent, (2) a
lower concentration of bromide ion, (3) a higher free sulfite ion
concentration and (4) a higher pH, in comparison with the litho-developer.
On the other hand, the time-passage exhaustion replenisher, replenisher
(RO), contains (1) a higher concentration of the developing agent, (2) a
substantially identical concentration of bromide ion (e.g., within a range
of .+-.20% by weight), (3) a higher free sulfite ion concentration and (4)
a lower pH, in comparison with the litho-developer.
In comparing the process exhaustion replenisher (RD) with the time-passage
exhaustion replenisher (RO), the following important characteristics
exist: (1) the developing agent concentration of the process exhaustion
replenisher (RD) may be the same as or different from that of the
time-passage exhaustion replenisher (RO), (2) the bromide ion
concentration of the process exhaustion replenisher (RD) is lower than
that of the time-passage exhaustion replenisher (RO) (3) the free sulfite
ion concentration of the process exhaustion replenisher (RD) is also lower
than that of the time-passage exhaustion replenisher (RO), and (4) the pH
of the time-passage exhaustion replenisher (RO) is lower than that of the
process exhaustion replenisher (RD).
The concentration of each of the components and the pH in each of the
replenishers of the present invention are determined relatively depending
upon the concentration of each of the components and the pH in the
litho-developer to be used and, therefore, in view of this, it is
difficult to set forth unequivocally their respective concentrations and
pH's.
However, for the purposes of comparing these characteristics of the
replenishers used in this invention in relation to each other and to the
lithographic developer, the characteristics set forth in the following
table are exemplary.
______________________________________
Lithographic
Replenisher
Replenisher
Developer (RD) (RO)
______________________________________
Lithographic
Developing 10-30 20-50 20-50
Agent (g/l)
Free Sulfite
Ion Concen- 1-6 2-7 7-20
tration (g/l)
Potassium
Bromide (g/l)
1-5 0-1 1-5
pH* 9-11 9-11 9-11
______________________________________
*The pH of replenisher (RD) is greater than that of the lithographic
developer and the pH of the lithographic developer is substantially equal
to that of the replenisher (RO).
In addition, since the concentrations of other components in each of the
replenishers employed in the present invention, other than the
concentration of the developing agent, the bromide ion concentration and
the free sulfite ion concentration and the pH as described above, are not
limited or restricted, they do not need to be described in detail and they
may be the same as or different from those of the litho-developer used.
Next, the term "development activity" as used in the description of the
present invention will be illustrated below. The development activity
cannot be expressed as a numerical value by only one, easy measurement,
unlike the pH or so. The description to "maintain the development activity
constant" as used herein means that the concentrations of each of the
essential components, namely, the developing agent, the bromide ion and
the free sulfite ion, and the pH of the litho-developer used is kept
substantially identical to those of the fresh litho-developer which
results in the ability to achieve photographic characteristics identical
with those which were obtained using the fresh litho-developer.
The term "substantially identical" as used herein means that the
concentrations of the essential components and the pH each is within the
respective range wherein photographic characteristics, for example, the
sensitivity, the dot quality, the half-tone gradation and/or the phenomena
called "black spot or comet" in this art (e.g., as described in Japanese
Patent Application (OPI) No. 20527/1973 (corresponding to British Patent
No. 1,365,236), page 4, line 15-20) are at a level identical to that which
is obtained by the fresh litho-developer. Accordingly, whether or not the
development activity is maintained constant can be evaluated by a chemical
analysis of the essential constituent elements or from a comparison of
photographic characteristics, as hereinafter described in detail.
In general, a litho-developer is prepared by mixing a portion containing,
as a main component, a developing agent (hereinafter designated portion
(A)) with another portion containing, as a main component, an alkali agent
(hereinafter designated portion (B)) just before use, because a
litho-developer is particularly easily subject to aerial oxidation.
Likewise in a replenisher, it is preferred to add a mixture of portion (A)
and portion (B) to the litho-developer as soon as possible after the
mixing thereof. For example, in U.S. Pat. No. 4,025,344 and in German
Patent Application (OLS) No. 2,343,242, a replenisher is prepared just
before addition by mixing a portion (A) and a portion (B) and optionally,
water, in the respective amounts required to supplement the
litho-developer and then, all of the replenisher prepared is added to the
litho-developer in the tank of an automatic developing machine; or portion
(A) and portion (B) are directly added to the litho-developer without
prior mixing of these two portions.
In the present invention, the manner of addition of the process exhaustion
replenisher (RD) is not particularly restricted and, therefore, it can be
added in any manner generally used in this art.
For instance, the quantity of the process exhaustion replenisher (RD) can
be determined by monitoring the blackened area of a processed film and
then, determining the amount of the process exhaustion replenisher (RD)
needed in proportion to the blackened area, or the quantity of the process
exhaustion replenisher (RD) can be previously determined from the kind,
size and exposure of the film to be processed, which quantity of the
process exhaustion replenisher (RD) is added after the processing of each
sheet of film. Also, in the case of roll films, a prescribed amount of
process exhaustion replenisher (RD) may be added at constant time
intervals (e.g., at constant time intervals ranging from 30 sec to several
minutes) depending on the amount of films processed.
These addition methods can be carried out with reference to the
descriptions as disclosed in, for example, U.S. Pat. Nos. 3,529,529,
3,532,047, 3,334,566, 3,554,109 and 4,025,344.
A remarkable feature of the present invention is that the time-passage
exhaustion replenisher (RO) can be added in a simple and practical manner.
More specifically, when the operation of an automatic developing machine
has been suspended and the operation is again started sometime later, the
time-passage exhaustion replenisher (RO) is added in a supplemental amount
which can be previously determined depending upon the time interval of the
suspension of the automatic developing machine and the ambient temperature
at which the developer is maintained during the time interval of the
suspension. On the other hand, replenishment with the process exhaustion
replenisher (RD) plays an important roll during the operation of the
automatic developing machine. Concerning the time-passage exhaustion which
occurs in the litho-developer during operation of the automatic developing
machine, various simple replenishing methods can be employed, because the
extent of exhaustion of a litho-developing attributable to the passage of
time during operation is much smaller than that attributable to the
processing, although it is not negligibly small. For instance, in a
similar manner as disclosed in German Patent Application (OLS) No.
2,044,893 and U.S. Pat. No. 4,025,344, during operation of an automatic
developing machine, a prescribed amount of a replenisher to compensate for
developer exhaustion due to the passage of time is added at regular time
intervals during periods when the automatic developing machine is being
used, i.e., films are being processed, or during periods of interruption
when the automatic developing machine is in operation but no films are
being processed, i.e., during stand-by periods, e.g., within the range of
10 minutes to 4 hours, perferably, 30 minutes to 3 hours, or supplemental
quantities may be added initially at the start of the operation after the
interruption thereof.
In addition, the above-described supplemental amount of the replenisher to
compensate for the passage of time is previously determined depending only
upon the time interval which has elapsed, regardless of the quantity of
films treated. Processes for determining this supplemental quantity are
illustrated hereinafter.
The term "interruption of operation" is used herein to describe the
situation where the automatic developing machine is running, but no films
are being processed, (i.e., stand-by operation) and the term "suspension
of operation" is used herein to describe the situation where the automatic
developing machine is turned off with developer being allowed to remain in
the automatic developing machine.
Where the operation of an automatic developing machine has been suspended,
the time-passage exhaustion replenisher (RO) is not added at all to the
litho-developer used during the period of suspension, but it is added in a
supplemental amount which is determined by the time interval of the
suspension and the ambient temperature during the time interval of
suspension when the automatic developing machine is next operated.
Each of the supplemental quantities of the time-passage exhaustion
replenisher (RO) to be added in the course of the operation and at the end
of period of suspension of an automatic developing machine can be easily
determined depending on the automatic developing machine, the composition
of the litho-developer and the composition of the time-passage replenisher
(RO). For instance, where a developer having an initial composition is put
in a tank of an automatic developing machine and such is operated for a
short while, e.g., for 2 hours, and as a result, the developer becomes
exhausted, the quantity of time-passage exhaustion replenisher (RO) to be
supplemented in order to restore the developer, which has thus changed, to
the initial level can be determined by chemically analyzing the resulting
exhausted developer. Similarly, where operation of the automatic
developing machine has been stopped for a short while, e.g., for 2 hours,
and the developer is left in the tank thereof during that time and, as a
result, the developer is exhausted, the quantity to be supplemented in
order to restore the developer, which has been changed, to the initial
level can be also determined by a chemical analysis of the resulting
exhausted developer. The temperature at which the developer is kept during
the interval of suspension of operation of the automatic developing
machine depends upon the ambient temperature of the automatic developing
machine. Therefore, the developer which deteriorates by being left in the
tank of the automatic developing machine for a prescribed time is stored
at a wide variety of temperatures. The developers obtained are then
chemically analyzed using techniques generally employed in the
photographic art to determine the quantity of replenisher necessary to
restore the developer to the initial level at each ambient temperature.
However, a constant ambient temperature may be achieved throughout the
year by thermostatically controlling the ambient temperature or in a room
lacking such an equipment, since the difference in the extent of
deterioration resulting from differences in ambient temperature is not so
sharp, the year may be divided into 2 or 3 seasons and a respective
ambient temperature for each season is established. Under these
approximate conditions, the quantity of the time-passage exhaustion
replenisher (RO) to be supplemented can be determined with an accuracy
adequate for practical use.
Various analytical techniques can be employed for the chemical analysis of
developers and replenishers. For instance, G. Russell, Chemical Analysis
in Photography, page 205-225, Focal Press (1965) describes suitable
techniques which can be used.
In addition to chemical analytical techniques for determining the
supplemental quantity of the replenisher required, the development
activity can be also restored by adding the replenisher in an amount
determinable from a comparison of photographic characteristics.
More specifically, the quantity of replenisher required for restoring the
photographic characteristics (e.g., the sensitivity, the gradation, the
dot quality, the half-tone gradation and freedom from black spot) to the
level obtained by processing with a developer having an initial
composition can be routinely determined by trial and error.
The decrease in development activity (1) where the developer is left in the
tank of an automatic developing machine while operation of the automatic
developing apparatus is suspended for a variable time yet the temperature
of the developer is kept constant and (2) where the developer put in the
tank of an automatic developing machine while the operation of the
automatic developing machine is suspended for a prescribed time and the
temperature is changed is shown graphically in FIG. 1 and FIG. 2,
respectively. As can be seen from these figures, the decrease in the
development activity of the developer can be correlated to the time
interval of the suspension of the operation of the automatic developing
machine and the temperature of the developer during the time interval of
suspension thereof and, further, each of the relationships between the
decrease in the development activity and the suspension time, and between
the decrease in the development activity and the temperature of the
developer at a temperature higher than 10.degree. C. can be regarded as
approximately linear. When the time interval of suspension of operation is
prolonged over a certain extent, the temperature of the developer comes to
equal the ambient temperature. Accordingly, the temperature of the
developer may be considered to be that of the ambient temperature without
any large discrepancy occurring. Accordingly, the supplemental quantity of
the time-passage exhaustion replenisher (RO) (R, in liters) to the
decrease in the development activity during the period of suspension of
the automatic developing machine can be represented by the following
relationship, wherein T (in hours) is the time interval of suspension, and
t (in .degree.C.) is the ambient temperature:
(I) When t is above 10.degree. C.,
R=.alpha..multidot.T t-10/10
(II) When t is above 0.degree. C. and 10.degree. C. or less,
R=.alpha..multidot.T/10
wherein .alpha. is a constant depending upon the nature of the automatic
developing machine used, e.g., agitation method, film transport method,
etc., the ratio of the surface area of the developing tank to the volume
thereof, the developer composition, the kind of photosensitive film, the
average number of films which have been development-processed and so on,
and can be determined experimentally in a conventional manner. For
example, when the supplemental quantity of the time-passage exhaustion
replenisher (RO) was determined to be 1.4 liters in a conventional manner,
for example, using a control film strip, under conditions of a period of
suspension of 14 hours and an ambient temperature of 25.degree. C., the
following value can be obtained as the value of .alpha.,
.alpha.=R/T.multidot.10/t-10=(1.4.times.10)/(14.times.15)=0.067
Accordingly, the supplemental quantity of the time-passage exhaustion
replenisher (RO) under the conditions of a temperature of 23.degree. C.
and a period of suspension of 38 hours can be calculated as 3.3 liters
using the .alpha. value obtained above as follows:
R=0.067.times.38.times.13/10=3.3
While such calculations may be done as the occasion demands, it is
convenient to determine previously calculated R values under various
appropriate conditions and put them in a table or plot them graphically
because the above-described relationship contains only the period of
suspension and the ambient temperature as variables in a series of
development-processings using combinations of a specific automatic
developing machine, a specific developer and a specific kind of film.
Of course, the .alpha. value must be determined for each system since the
.alpha. value will vary even if only one of the automatic developing
machine, the developer and the kind of film to be used is changed.
However, once the .alpha. value has been determined, R values can be
calculated simply from the above-described relationship. Therefore, this
method is of great advantage in the photolithographic plate-making art
wherein a large number of films of the same kind are processed using the
same kind of developer and the same type of automatic developing machine.
As was described above, where the supplemental quantity per unit time
(e.g., per hour) has been initially determined for a specific
developer/replenisher/automatic developing machine system under each of
the conditions to be used, namely, whether the operation of the automatic
developing machine is continued or suspended, the supplemental amount to
be added in each case of different time periods of duration of operation
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