DE1447801A1 - Photographic material and process for its manufacture - Google Patents

Description

Patent attorney Dipl.-Phys. GERHARD LIEDL- Munich u, dumiauMJtr. 22

mU62 Fern-., hrüber 05 /? 2 208

H478Q1 a 1910

TOX CORPORATION, Webster, NEW YORK / U.S.A.

Photographic material and process for its manufacture

The invention relates to silver halide photographic materials and, more particularly, to materials such as those produced by evaporating the silver halide under reduced pressure and elevated temperature and condensing the silver halide vapors onto a suitable support material. The silver halide vapor condenses as a layer of silver halide microcrystals which are supported on the substrate by being

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adhere directly to the carrier and to each other. Am such material differs from emulsion or gelatin photographic syrber halide materials in that the the latter consists of the silver halide grains in a matrix. Binder are embedded, which isolates the grains from each other and from the carrier and at the same time fulfills the puncture, which To hold grains on the carrier. Accordingly, a vapor-deposited silver halide layer can be said to be binder-free will. This term is used to distinguish the materials of the present invention from silver halide photographic materials of the emulsion or gelatin type.

Silver halide photographic materials include silver bromide, silver chloride, silver iodide, and mixtures of these materials. "For For most photographic purposes, silver bromide is used as the dominant silver halide component, with consideration smaller amounts of iodide and / or chloride can be included for special effects or properties. Although the For the purpose of illustrating the present invention, However, the invention is intended to include specific examples using silver bromide as it is the most important photographic silver halide this substance, not be restricted ·.

There are already several proposals known Gewais & e », vaporized Silver halide materials for photographic use. deliver, for example from US Patents 1,970

90 9,608 / 097 1

and 1,999,088 (de Boer et al), U.S. Patent 2,945,771 (Mansfeld) and French Patent 1,357,623 (Lu Valle et al.) · The two patents mentioned in the first place relate to flash or rapid evaporation of silver bromide. There is a lot of silver bromide on an open heating wire attached, whereupon it is evaporated very quickly on a carrier under low pressure in a few seconds. In the U.S. Patent 2,945,771 becomes this flash vaporization process modified into a continuous process in which the silver halide is transferred from a crucible to a moving one Carrier strip is evaporated. The above French patent relates to refinements in manufacture such photographic material. In the work on which the invention is based, relating to production Evaporated silver halide photographic materials have been found to apply the teachings of the prior art in several ways Were inadequate, especially with regard to the production of a vapor-deposited silver halide material, which could compete economically with the emulsion materials. At the same time, certain improvements were made found in the manufacture of this material to improve the photographic properties of the product.

In the procedure according to the two USA patents mentioned in the first place above, the silver bromide is in an open Filament applied and then for a time of some

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Vaporizes quickly in seconds, with the thread being heated to around 700 - 800 ° C. Since silver bromide melts at 434 ° 0, it is obvious that during the few seconds of the evaporation process the evaporation begins essentially at the melting point and continues in the following seconds if the temperature of the silver bromide rises to any unknown value. Since the character and properties of the deposited silver bromide depend on the evaporation temperature, the resulting layer is not uniform in its photographic properties leading photographic plates to differences in their properties and that "frh so uniformity des.Erzeugnisses not be achieved.

The last two patents mentioned above are these problems have been overcome at least to some extent. However, it is expressly stated in both patents that the Evaporation of silver bromide from a crucible at relative continuous and stable conditions, the silver bromide cannot be heated above its decomposition temperature may, a temperature which, according to the information in de »Idteratua? is at 700 ° C. During the short heating-up period "as described in the two patent specifications mentioned above in the first place" is used, if it is similarly very untrue- * "* '■

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It's embarrassing that any part of the silver bromide is above 700 ° C is heated.

In contrast to these previous teachings it has now been found that a vapor deposition of silver under high vacuum in an effective V / else, starting ron a melt of the silver halide can be carried out at temperatures which are considerably above the decomposition temperature of the silver halide. For example, silver bromide; successfully evaporated at temperatures that were well above its decomposition temperature, and at temperatures of the melt pool that were up to about 765 ° C, the; Vapors were condensed on conventional photographic carrier materials, for example white baryta paper, triacetate film and Cronar.

The products obtained in this way showed photographic properties, those with those that result at evaporation temperatures below the decomposition temperature, in are advantageously comparable. For example, the higher evaporation temperature yielded according to the invention photographic layers with higher photographic sensitivities, than they belong to those strata which, under the same conditions, apply a lower evaporation temperature. Of the vapor deposition at higher temperatures

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however, the ability to coat a substrate at a much higher speed. If, for example, silver bromide ■ is evaporated from a molten bath at a temperature of about 620 ° C and the results obtained are compared with a vapor deposition of silver bromide, which is carried out at a 'temperature of the molten bath of about 765 ° 0, it follows that at the same thickness of the coating, the latter temperature allows a deposition rate which is about ten times greater than that at the former temperature. This unexpected increase in the rate of deposition can be achieved despite the inherently detrimental role that the decomposition of silver bromide plays at the elevated temperature. If, for example, a carrier strip is coated by vapor deposition of the silver bromide under high vacuum from a molten bath that is contained in a crucible whose length corresponds to the width of the strip and is itself approximately 63 μm wide, with a vaporization temperature of the silver bromide of 62 ( Q ⁰ 0 the strips are moved across the crucible at a speed of only about 13 m / min. So as to produce a silver bromide layer on the strip about 0.4 microns thick is used, the "strip can be moved over the crucible at a speed of about 130 m / min. under the same conditions in order to produce a silver bromide layer on the strip with a thickness of also about 0.4 microns.

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• Gemäß.der invention is a photographic layer of listed] dampftem silver mediated, at which the evaporation of the halide is carried out under reduced pressure and at a! _F temperature above the decomposition temperature of the halogen represents idea lies ·

Furthermore, according to the invention, a photographic material is intended. with a vapor-deposited layer of silver halide are suggested *! wherein the evaporation luf dee halide of a aofcjselabad of ßllberhalogenides carried out at reduced Druok wherein Al · temperature of the whole above the Sohmelzbades

of the silver halide.

According to the invention, a photographic film is to be formed in which the main silver halide constituent is silver halide »

The related fee friction of preferred embodiments according to the invention is used in connection with the accompanying drawing to further explain the invention.

Itfe · 1 fllti eoheja & table view of a vacuum installation as it can be used when carrying out the opening j

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Pig. 2 shows a cross-sectional view of the device from Plg.1 along the line 2-2 of Figure 1 and

Pig. 3 shows a cross section of the device from Pig.1 along line 3-3 from Pig.1, however, parts l are in a different operating position.

In the drawings, for example, an apparatus for the vapor deposition of silver halide under high vacuum and at high temperature is shown schematically. The device comprises a substructure 10 with a plate 11 attached to its upper side. A bell 12 is detachably arranged on the plate 11. The surface of the plate 1t and the contact surface of the bell 12 are ground and machined so that a high vacuum is guaranteed between them . The evacuation of the space under the G-looke takes place via a line 40 by means of a pump 41. Of course, such a pump system is used that a high vacuum with a minimum of impurities in the atmosphere; can be reached under bell 12 '«" · · _.:

In the middle of the plate 11 is on a support frame H a Platform 13 arranged, the holder of an evaporation crucible 32 is used. Preferably the crucible 32 from which daa

Silver halide is evaporated, used directly as an electrical heating element, which is done by the fact that the Sohmel crucible is made of tungsten, for example. In this case . '' \

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the indene of the crucible are designed so that on them with Aid from terminals 33 and 39 or the like »supply lines 34 attached can be. If the leads 34 with a corresponding electrical voltage source 35 are connected, acts the tungsten crucible 32 directly as a resistance heater to to melt and evaporate silver halides thus introduced into it.

At a suitable distance above the crucible 32 and the platform a Supported out of carriers 17 stator 16 iet provided. The stand 16 has a central opening 18 which, in the illustrated embodiment, has a rectangular shape. This opening is covered on its upper side by a stationary counter-plate 19, while a movable screen or a movable screen 20 is provided on its lower side. The screen 20 can be swiveled by rotating a shaft 30 on the handle 31, from a position in which it lies below the opening 18 and covers it, into a position in which it is shown in FIG. 3, this opening completely releases.

The stand 16 also carries a tape feeder which includes a take-up roll 23 and a feed roll 24. The hell 25 is rotatably supported on a pair of support arms 21, dl · ihrereeite on the stator 16 are attached. The cave 24 is similarly attached to a corresponding pair of support arms

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supported. These roles are so on. Stand 16 arranged, that they are feeding a strip 2.9 from the feed roller 24 allow under the lip 19a of the counter plate 19, then a guide of the strip across the opening 18 and finally via the lip 19b out of the opening to the take-up roll 23 · In this way, a strip 29 of any Material from the roll 24 · across the opening..18 of the roll 2? are fed. When the screen 20 is removed from the opening the strip 29 is exposed to the vapors generated during its course across the opening-exit the crucible 32, -Im the rest is the strip against these vapors through the Stand 16 practically completely shielded.

The drive of the strip 29 takes place via a motor 36, the. acts on a shaft 25 ^ via bevel gears 37 and 38 * Am upper end of the shaft 25 connects another pair of bevel gears 27 and 28 the shaft 25 with a stub axle 26, which in turn is connected to the take-up roll 23.

All elements which extend from the inside of the vacuum chamber ¹ to the outside thereof, for example the shafts 25 and 30, the supply lines 34 and the vacuum line 40, run through suitable seals provided in the dex plate 11.

In the method according to the invention, the crucible 32 with the required amount of silver halide, for example

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H47801

'SiliserbroBtid, Silber ^ odid, Silberohlorid or with a micro- resistance of this Substanaon, loaded' trap desired, can 'also a plurality of Sohmelziegel 32 on the platform

placed and electrically heated independently, with a container «in specific halide and another container may contain another halide. Optionally, both containers can also contain the same halide. For the For most photographic purposes, the last vapor deposited is two-medium predominantly silver bromide. A stripe a conventional photographic carrier material, for example «Photobase» ^ paper, or an acetate or mylar film wound onto the roll 24, transversely, guided over the opening 18 and connected to the roller 23. The aperture 20 is set so » that it closes the opening 18. Then the Ölooke 12 is sealed against the plate 1t and the vacuum pump is put into action ^ around which the bell 12 and the Plate 1t to evacuate defined chamber. For the purposes of the present invention, the working pressure within the Glass or vacuum chamber to about 10 to 10 mm Hg «In some cases a pressure between about 10" "* and 10 mm Hg is applied» whereby a pressure of about 5 times 10 * "'mm. Hg has proven to be particularly useful. When the pressure within the vacuum chamber has reached the desired value, current is supplied to the crucible 52 in order to reduce the pressure inside to melt the silver halide and bring it to the desired evaporation temperature.

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According to the invention, this is the evaporation temperature chooses that it is above the decomposition temperature of the halides' j is preferably "considerably above this temperature. In the case of silver bromide, for example, the temperature of the Sclunelabad in seal 32 should be considerably above 700 ° 0, which is the decomposition temperature given in the literature. Clay silver bromide is «the range from about 725 to 765 ° G or even higher is preferred, with the top being this Area is more effective. If too high a temperature is used Is used, the decomposition speed or the ' Decomposition ratio of the silver halide so great that the Effectiveness of the "procedure" is impaired.

When the pressure and the temperature have reached the desired values and are essentially stable, that is to say they are constant to plus / minute a few C, the screen 20 is opened ₉ so that the silver halide vapors emerging from the crucible 32 are absorbed . hit the rope of the strip 23 located in the opening 18 ″, condense there and crystallize in a microcrystalline form. *

In addition, the motor 3β is now activated, so that the hollow 23 · is driven and the strip 29 advances over the opening 18. The feed speed of the strip can be used the thickness of the silver halide absorption on the strip at " a given set of other operating parameters.

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-13- 1U78Q1

For optimum photographic properties preferably the Silberhalogenidniederechlag on the strip 29 should be very thin and are in the range of a fraction of a micron, preferably between about 0.1 and about 0 _f 5 microns, which of the currently used carrier and the desired photographic properties of the material depends.

In order to obtain a substantially uniform deposit of silver halide on the region of the strip 29 advancing over the opening 18, it is preferred that the seal 32 have a length which at least approximately corresponds to the width of the strip 29 or the corresponding width dimension of the opening 18. It will also be apparent that the strip 29 is positioned at a sufficient distance from the crucible 32 so that it does not heat up to a temperature which prevents the deposition of the vaporized silver halide. For the evaporation temperature of the silver halide given above, it has been found that a distance of the crucible 32 from the strip 29 in the opening 18 of about 8.7 cm is suitable. Under these conditions it was found that the strip assumes a temperature of about 50 ° C. Piping physical parameters of the opening obviously be varied "The strip may be substantially teaperaturgeeteuert regardless of its distance from the crucible 32, through artificial and controlled cooling 18 covering Q-egenplatte 19 at which the strips 29 abut a Vorsohub at · can.

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' ' ·. £ 1 * 101/0071

H47801

Above foer © d put its ,, warns the previous relevant •! Eclmilc before producing the vapor-deposited, photographic SilberhalogeiriSschichten, are presumably that Verdampfungetemperaturen obsrfearb the Zersetgungeteiaperatur of "relevant Silberhälogenidss" fiaiis eat. Contrast, show the results of the present invention to that comparable photographically © characteristics with Sllberhalogenidsehichten.erzielen blank which are prepared by _s that the silver halide is deposited at the 5emperaturen _t considerably above the Zersetzungstemperp / feur of the silver halide are, with reference. eA ^ -ScMchteri that "at temperatures below "In fact, with these temperatures, according to the invention," higher photographic, sensitivities "can also be achieved of the silver halide layer can be increased to about 50 times or more in comparison with the speeds that can be achieved on the basis of the teaching that has become known up to now. "-.- ■

The following special examples serve to further elucidate

3 the samples of the. In the mnteß. t & fe * llie? 1s®2i. Eeiipielen imtaten fotografia ^ ca materials were all produced in the following way: Strips made of fiberglass made of barite paper

in the apparatus shown in the drawing in the above beeohriebenen Catfish brought in. The crucible is charged with pure silver bromide, for example silver bromide, as appropriate the Malinowski method described in Journal of Photographic Science, VoI 8, 1960, 36ite 69 to 71 The bell 12 is then sealed with the vacuum plate 11. The vacuum chamber is closed for about an hour

-5 evacuated to a steady-state stabilized pressure of about 5 x 10 · mm Eg. The silver bromide is then heated to a stable temperature, the value of which is given for each example in the table below. The shutter is then opened and the paper strip is advanced across the opening 18 at a speed which causes a uniform deposition of silver bromide on the paper carrier of about 0.4 micron dial. This thickness turned out to be photographically optimal for the carrier material used. Because of the "present in the Papleretretffcn Restgaees, the pressure at the beginning of the coating and the strip Vorrüokens reached a value Tön about 5 x 10 ** ^ mm Hg during the P.sschichtungsoperktioifli. Dit tio ge \ ^) nnenen photographic products were in Similarly W * ii · beilohtet duroh'ein optical image and developed. The average photographic properties of these Prob "• ind listed in table naohßtehender ι

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Aa-hardened. Through through

Evaporation temperatures. sectional

the silver bromide - before sensation- Gamma ^ Emp-

meltness sensitivity)

example I. 630 ° 0 example II 715 ° G example III 750 ° ö

O. o5 0 .8th 0. 09 0 .6 0. 15th 0 .5

By comparing Example I with Examples II and III it can be easily determined that evaporation temperatures, des Silver bromides above the decomposition temperature of 700 ° 0 produced photographic samples whose sensitivities were twice as high were three times better than the samples produced at the low evaporation temperature of 63.0 ° 0.

The developer used in the preceding examples was a modified Mitchell-Entwioklejc · with the following composition t

solution

1.25 g gelatin suitable for photographic purposes,

diluted with water to 250 ml. The gelatin is left swell in 5 ml of cold water, fill up the specified volume with boiling water, lets it cool down and stores the solution in one Refrigerator.

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U4780.1

Bt

78 g sodium carbonate anhydride (or 91.26 g mono-

hyärat)
• 2.0 g of potassium bromide

made up to 1 1 with water.

Solution qi

0.50 g Elon or Metol (N-Methy1-p-Aminophenol surface} 19.50 g sodium sulfite (anhydride) 1.87 g HQ

Dissolve in water in the following order} Sulphite, Metol, IfQ. It is then diluted to 250 ml with water.

It provides the solutions A, B and 0 and starts passing 75 ml of sodium thiosulfate per 1 # -igee 1.9 1 (1/2 g & l) Bntwlckler added the developer of equal volumes.

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Claims (1)

Claims • Process on the application of silver halide in a vacuum a pad with evacuation of a G-ehäuses in which a container for holding a silver halide supply and a supply of supporting material at a distance from this container is arranged, characterized in that the silver halide is heated and. is held at a temperature above its decomposition temperature, and that the documentation material is exposed to the evaporated silver halide in order to a microcrystalline concentration of evaporated silver halide 2 · The method according to claim 1, characterized · that the Exposure duration of the document material versus the evaporated Silver halide is not chosen to be significantly larger than it for the deposition of a layer of silver halide with a thickness © of about 0.5 microns is required. 3. The method according to claim t or 2 ', characterized in that that silver bromide is at least predominantly used as the silver halide and that the temperature affects a throw 700 ° .ö is set « 909Ä0S / G971 t 1 4 _# Method according to claim 3, characterized in that the !! temperature is always about 700 and 765 ° O selected. ' / · ■ ■ ■ "5 · method according to claim 3» characterized in that , the! temperature is chosen between about 725 'and 765 ° O. 6 «Method according to one of the preceding claims» thereby characterized in that the housing is pumped to a pressure kielner than about 10 mm Hg and that the silver halide is heated while maintaining this pressure and is kept essentially stable at a temperature, which is above a decomposition temperature » 7 · Method according to claim 6, daduroh marked that ρ C the pressure is chosen between about 10 and about 10 mm Hg, 8. The method according to any one of the preceding claims, daduroh characterized in that a crucible is used as the container for the silver halide 9 · Method according to one of the preceding claims, characterized in that a strip »., is used and "that this strip is fed past the opening of the container so as to create successive sections of the strip to expose the evaporated silver halide and the vaporized silver halide on the backing ■ 809808/0971 -ZV- rnaterial r-ufsusamiaoln, as well as that the feed rate of the strip is chosen so that there is a microcrystalline Layer of silver halide of a desired thickness is deposited. 10. The method according to any one of the preceding claims, characterized characterized in that the base material, while it is being applied to the evaporated silver halide, outgasses. 9 0 9 8 0 8/0971 ^{BAD 0RiQINAL}