Agfa Gevaert Nv

Agfa-gevaert

Benedictus J Jansen

Frank P Michiels

Werner J Van De Wynckel

Andre Roefs

Ann L Verbeeck

Freddy Henderickx

Francis J Sels

Hendrik E Kokelenberg

Raymond L Florens

Marc A De Niel

Dirk F De Ruijter

Pieter Perdieus

Marc J Scheerders

Herman M Engels

Fernand I Ketels

Bartolomeus J Verlinden

Paul Smet

Michiels Frank

A method of processing an exposed black-and-white silver halide photographic film material, the method having the steps of developing in a developer solution, fixing in a fixer solution, replenishing of fixer and developer solution, rinsing in a washing solution and drying, characterized in that fixing is performed in one step and under such conditions that a 'silver equilibrium ratio' of less than 2.0 is maintained, the said ratio being defined as the ratio between actual by the film material in the rinsing step through carry-over (cross-over) of silver from the fixing solution to the washing solution and amount of silver brought into the washing solution and the total amount of silver that theoretically could be brought into the washing solution by the film material by such carry-over; a 'fixer to film silver ratio' of less than 0.2 is obtained, this ratio being defined as the ratio between silver content in 'running equilibrium condition of the fixer' and amount of silver in the film material to be fixed in the fixing step, wherein said 'running equilibrium condition of the fixer' is the condition attained after having replenished said fixing solution twice. By this method an ecologically favourable minimization of silver content in the washing solution has been obtained without impairing the processing speed, without enhancing processing costs and without excessive regeneration.

Processing method of black-and-white photographic materials

A method of processing an exposed black-and-white silver halide light-sensitive photographic material has been disclosed, said method comprising the steps of developing in a developer solution, followed by fixing in a fixer solution, comprising a hardening agent, preferably a compound providing aluminum ions, and wherein, in running equilibrium conditions, said fixer solution has a pH of at least 4.3, further adding to said fixer a fixer replenisher at a rate of from 0 ml/m.sup.2 up to 300 ml/m.sup.2 ; followed by rinsing and drying, wherein rinsing between developing and fixing is excluded and wherein an .alpha.-ketocarboxylic acid structure in an amount of from 0 to 3 g per liter is present in the said fixer solution while starting processing or in the said fixer replenisher, characterized in that said developing step is performed in a developer comprising, in an amount of from 5 g up to 100 gram per liter, a developing agent corresponding to the formula (I), a precursor and/or a metal salt thereof given in the detailed description and in the claims hereinafter. Most preferably 1-ascorbic acid, iso-ascorbic acid or (tetramethyl) reductic acid is used as a developing agent.

Method of processing a black-and-white silver halide photographic

A method is disclosed of processing an exposed black-and-white light-sensitive silver halide photographic material having silver halide, coated in an amount, expressed as an equivalent amount of silver nitrate of less than 6 g/m.sup.2 comprising the steps of developing, fixing, rinsing and drying, making use in the developing step of an ascorbic acid type developer and of an equivalent developer replenisher providing a regeneration amount of less than 150 ml/m.sup.2, characterized in that the said material has a buffering capacity of less than 6 mmole/m.sup.2, wherein said buffering capacity is defined as the amount of alkali, expressed in mmole/square meter, required to bridge across pH differences between the material and the developer.

Processing of radiographic materials having emulsion grains rich in

An apparatus for de-silvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). Operation of the cell (10) is controlled potentiostatically while the current exceeds a certain threshold value and the current is controlled galvanostatically at that threshold (minimum) value in circumstances in which the potentiostatic control would result in a current below the threshold value. To this end, the power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) for controlling operation of the cell potentiostatically at a selected cathode potential, means for monitoring the current drawn through the cell during such potentiostatic control and for comparing such current with a threshold current, and means for controlling the cell galvanostatically at such threshold current value, means for switching from potentiostatic to galvanostatic control in response to cell current dropping below said threshold value, means for periodically re-establishing said selected cathode potential, and means for reverting from galvanostatic to said potentiostatic control in response to a cell current above said threshold value when said selected cathode potential is re-established.

Process and apparatus for desilvering a silver-containing solution

A method is disclosed of processing in a processor an image-wise exposed black-and-white light-sensitive silver halide photographic material comprising the steps of developing in a developing solution and fixing in a fixer solution, characterized in that upon starting of the processing the said fixer solution comprises a mixture of a fixer starter solution and a fixer replenisher solution, in that said fixer solution is replenished with the said fixer replenishing solution and in that the said fixer starter solution is a developing solution.

Method of processing light-sensitive silver halide photographic materials

A method of processing photographic material comprises developing the photographic material by treatment with a developer (26), and fixing the developed photographic material by treatment with a fixer (32, 38) while reducing the level of silver ions in the fixer (38) by electrolysis. Between the developing and the fixing, the photographic material is treated with an intermediate treatment liquid (44) for a period of time less than the treatment time with the fixer (32, 38). The intermediate treatment liquid (44) contains used fixer (38). The efficiency of fixing is improved without the use of substantially greater liquid volumes and in particular without the use of further quantities of water.

Method of processing photographic material

An apparatus for desilvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). The power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) to reduce the cathode potential, at least periodically, as the desilvering process continues. The process leads to better silver adhesion on the cathode occurs, while maintaining good desilvering levels in the solution, and cathode poisoning is minimised.

An apparatus for de-silvering a silver-containing solution, comprises a plurality of electrolysis cells (10, S1, S2) each having an anode (20, 120, 220) and a cathode (30, 130, 230). A master cell (10) further comprises a reference electrode (45). The remaining cell or cells constitute slave cells (S1, S2). Control means (41) adjust the cathode potential applied to the slave cells (S1, S2) in response to the current flow (I.sub.M) through the master cell (10). The apparatus is particularly suitable for de-silvering large volumes of silver-containing solution, without the use of high currents.

Apparatus and method for de-silvering a silver-containing solution

A silver recovery device (30) is described for removing silver from a silver-containing solution. The device (30) comprises an ion-exchange resin bed (34) and a pump (62) for directing the solution through the resin bed (34). The pump (62) is positioned downstream of the resin bed (34) and the resin bed (34) is held within a retaining space (36) of variable dimensions. Higher liquid flow rates are thereby achievable, without fluidization of the resin.

Silver recovery device and process

To eliminate the 'pi-line' artifact after processing a method of image formation is disclosed in a silver halide industrial X-ray photographic material, comprising on at least one side of a support, at least one gelatin silver halide emulsion layer and a total amount of silver halide, corresponding to from 6 to 20 g of silver nitrate per square meter and per side, and at least one non-sensitive protective antistress coating, wherein said material further comprises a hardening agent different from a vinyl sulphone compound, preferably formaldehyde, and at least one polyoxyalkylene compound as a surfactant in at least one of its hydrophilic layers, and wherein after exposure to direct X-rays said material is subjected in an automatic processing machine to the steps of developing in a developer comprising at least one anionic alkylphenoxy polyalkyleneoxy phosphate ester surfactant, fixing in a fixer which may comprise at least one alpha-ketocarboxylic acid, rinsing and drying.

Processing of silver halide photographic industrial X-ray films

An apparatus for the electrolytic recovery of silver from solutions containing silver is described. The apparatus comprises an electrolytic cell, an anode positioned within the cell, a reference electrode positioned within the cell, and a removable cathode positioned within the cell. The cathode has an inner face directed towards the anode and an outer face directed towards the reference electrode. The apparatus includes means for restraining the deposition of silver on the outer face of the cathode. The risk of incorrect potentials being sensed by the reference electrode are thereby reduced or avoided. The tendency for side reactions to occur is also reduced.

Apparatus for the electrolytic recovery of silver from solutions

Silver is recovered from the rinse water from a photographic film processing unit by means of a silver recovery device in which the rinse water is passed through at least one bed of ion exchange resin particles maintained in fluidized condition by the water flow. A plurality of such beds are preferably connected in series with rinse water being recirculated until fresh rinse water causes overflow to the next bed and finally to a collection vessel. Fluidization is interrupted periodically to create quiescent periods which aid in removal from the resin particles of accumulated gelatin from the processed film.

Silver recovery device

A process for developing a photographic material containing on a support an image-wise exposed silver halide emulsion layer of which the silver halide is substantially silver chloride and in which the photographic material before its exposure contains already at least one silver halide developing agent in a hydrophilic colloid binder in waterpermeable relationship with the silver halide, said process containing the step of contacting the exposed photographic material with an aqueous alkaline liquid, called activator liquid, being initially substantially free from developing agent(s), said contacting being not followed by a silver complex diffusion transfer processing, characterized in that said aqueous alkaline liquid contains a primary and/or secondary amine.

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Geel, Belgium

Benedictus J Jansen