DE1133979B - Process for the production of direct positive photographic images, particularly color-developed multicolor photographic images, by the reversal development process - Google Patents

Description

It is known to use direct positive black and white images and multicolor color developed photographic images Use the reverse development process to produce images. In the latter case, the in of the photosensitive silver halide layer in a black-and-white developer blackened. It is then watered and the remaining halogen silver with known Color developers converted to the desired multicolored positive image. Difficulty with this The process generally offers the gradation that is usually too steep and that is otherwise common Can only little influence measures in the emulsion production. The too steep gradation that Related to the reversal development was one of the main reasons why they differed from slides could not produce satisfactory supervisory images in a direct way. Another obstacle for that Production of direct positive multicolored images on paper backing using the reverse development process forms the so-called semolina. This means a patchy, uneven development, which gives the impression of a greatly exaggerated graininess. This grittiness will mainly caused by the black and white developer. They are responsible for this effect Alkalinity, the type and concentration of silver halide solvents, and the development time.

It has now been found, surprisingly, that these difficulties can be eliminated if the black-and-white development is carried out according to the process according to the invention. According to the invention, development is carried out by first allowing the photographic material to swell in a black-and-white developer free of bromine ions and then developing it in a black-and-white developer containing bromide. The first developer preferably contains only the developing agent and has a _pH value of less than 7. The benefits of this development process:

1. Shortening the development time. The sum of the times in the bromide-free prebath and the bromide-containing Developer can be kept considerably shorter than with conventional development. This is for machine processing, practically exclusively for reversal materials comes into question, an advantage that should not be underestimated, given the given throughput speed a shortening of the development time leads to the saving of developer tanks.

Method of manufacture

direct positive photographic images,

especially color developed multicolored

photographic images,
according to the inverse development process

Applicant:

Agfa Aktiengesellschaft,

Leverkusen-Bayerwerk,

Kaiser Wilhelm Allee

Dr. Karl Lohmer and Dr. Bernhard Morcher,

Leverkusen,
have been named as inventors

2. Reduction of semolina. The above-mentioned grittiness in multicolored pictures on paper backing disappears when processing according to the invention.

3. Flattening the gradation. When processing according to the invention, gamma values are obtained which are 0.3 to 0.5 units lower than with conventional processing.

4. Improvement of color rendering. This can probably be explained by the fact that in the development an exposed layer of a multilayer material in the first bath, the resulting reaction products diffuse into the adjacent unexposed layers and reduce the haze there, while in the places where none the three layers is exposed, a slight haze arises in all three layers.

5. A very good evenness and abundance of the developing baths, especially then if the bromide-free pre-bath has the same or a slightly higher concentration of the same developer substance like the bromide-containing developer bath.

209 627/292

The developing method of the present invention is of course not limited to materials with special documents or on certain shift arrangements. So can be used as a base for the light-sensitive material clear film, white film, paper or another support can be used. the Layers may contain various silver halides as a light-sensitive substance. The layer arrangement is arbitrary, then - in order to increase the impression of sharpness - the blue-sensitive layer can be used as the bottom layer Layer are arranged over which the green- and red-sensitive layers are located. If three layers of bromide silver are used, a filter layer is usually also present must be. The development process according to the invention can also be applied to individual layers and can therefore be used for the production of black and white positives.

"Phenidones" (legally zo protected trade name of Ilford = 1-phenyl-3-pyrazolidone) alone or in combination with Glycine in question. In principle, however, other developers or developer combinations can also be used. The first developer may contain other conventional additives such as antifoggants, stabilizers, and the like. The following example is intended to explain the new procedure without restricting it:

a) On a multilayer material that is used for the production of direct positive, multicolored images of color slides is intended, a wedge is exposed and in a developer of the following composition developed black and white.

2 g »Calgon« (legally protected trade name of the Benkiser company = polyphosphate 10 g sodium sulphate,
4 g hydroquinone,
8 g KBr,
4OgK ₂ CO ₃ ,

0.050 g of 1-phenyl-3-pyrazolidone, 1000 ml of water.

35

40

45

The development time is 5 minutes at 20 ° C. It is then processed further as usual. as The result is a wedge with good whites and rich blacks, but with a gamma value of 1.7. However, such a gamma value is useful for the reproduction of slide images too steep.

b) A similar wedge, as it was used in a), is in a developer of the following composition developed in black and white and then further processed as usual:

2 g »Calgon« (legally protected trade name of the Benkiser company = polyphosphate 4 g sodium sulfite,
6 g KBr,

4 g l-phenyl-3-pyrazolidone, 20 g potash,
1000 ml of water.

Even with a development time of 10 minutes, no whites are obtained, although the blacks because of the concealment of the top cast are unsatisfactory. The picture is also strong greedy.

c) The same wedge as in a) and b) is used for 1 minute at 20 ° C in a developer Composition treated:

4.5 g potassium metabisulphite,

4 g l-phenyl-3-pyrazolidone, 0.75 g NaHSO ₄ ,

5 ecm »Agepon« (trade name of

Farbenfabriken Bayer = sodium paraffin sulfonic acid), 1000 ecm of water,

and then immediately developed in the developer mentioned under b) for 4 minutes at 20 ° C and processed as usual. The result is very good whites and deep blacks. The 2-value obtained is 1.3 and is well suited for the reproduction of color slides. the in b) observed semeness does not appear here.

Claims (4)

PATENT CLAIMS: 1. A process for the production of direct positive photographic images, in particular color-developed multicolored photographic images, according to the reversal development process, characterized in that the black-and-white initial development is carried out in two stages, the first developer being bromide-free and from an aqueous solution of one or more consists of several developer substances, while the second bromide-containing developer consists of a conventional developer mixture. 2. The method according to claim 1, characterized in that that as a developer substance l-phenyl-3-pyrazolidone alone or in combination with Glycine is used. 3. The method according to claim 2, characterized in that the same in the prebath and the developer Developer concentration is set and the r ^ value of the prebath is essential is kept lower than that of the developer. 4. The method according to claim 1 to 3, characterized in that the sulfite concentration is kept the same in both developing baths. © 209 627/292 7.