CS264990B1 - Activation solution for processing of halogen-silver diffusion photomaterials - Google Patents

Abstract

The activation solution contains 3.5 to 4.5 wt. % of solvent of microcrystals or silver halides, 1.9 to 2.1 wt. % of alkali activating reducing agents, 5.9 to 6.1 wt. % of a mixture of substances maintaining a stable pH value, 2.95 to 3.15 wt. % of a mixture of substances increasing the diffusion rate, 0.55 to 0.65 wt. % of hydroxyethyl cellulose, 0.05 to 0.2 wt. % of l-phenyl-5-mercaptotetrazole, 0.05 to 0.2 wt. % of 2-mercaptoimidazoline and the remainder up to 100 wt. % of water.

Description

264990 2

The present invention relates to an activating solution for the treatment of halogen-free diffusion photo-materials to mediate diffusion transfer-recording of image information formed in an emulsion layer containing a silver halide and a reducing agent on an image or translucent transfer substrate.

For the treatment of halogen-free diffusion photomaterials containing in the light-sensitive layer, the reducing exposed silver halide is used activating solutions, which typically consist of an alkali activating reducing agent and a microcrystalline solvent, respectively. silver halides, which allow their diffusion from the light-sensitive layer of the light-sensitive material to the layer of the transfer substrate. These solutions may still contain various adjunct ingredients such as diffusion rate enhancers, veil suppressants, pH stabilizers and optical imaging enhancers.

Distilled water is used as the solvent.

Activation solutions known so far are protected by, for example, DE 3 020 262, JP 80 163 536, JP 8 124 349, US 4 357 407. However, their disadvantage is that when exposed to radiation in the near-violet to visible range, which is used in printing forms, it is shown created by diffusion transmission, smaller covering properties, thereby partially copying smaller elements of the autotypic representation of the printing form.

The above-mentioned drawbacks are eliminated by the activating solution for the treatment of halogen-free diffusion photomaterials according to the invention consisting of 3.5 to 4.5 wt. % of silver halide solvent crystals, 1.9 to 2.1 wt. reducing substances alkali, 5.9 to 6.1% by weight; mixtures of substances maintaining a stable pH, 2.95 to 3.15% by weight; diffusion rate increasing compound, 0.55 to 0.65% by weight. % of hydroxyethylcellulose, the principle of which is to contain 0.05 to 0.2 wt. 1-phenyl-5-mercaptotetrazole, 0.05 to 0.2 wt. 2-mercaptoimidazoline and the remainder to 100 wt. water.

This activating solution is suitable for the treatment of halogen-free diffusion photo-materials containing substances in the light-sensitive layer, reducing the exposed silver halide, and especially for the image intended for producing printing forms with pre-sensitized printing plates sensitive to the near ultraviolet to the visible region. An advantage of the activating solution according to the invention is that by using it, an image is produced by diffusion transfer of the brown-red to black color, thereby substantially improving its opacity when copying the printing forms with the UV light source compared to the previously used activating solutions. The following example illustrates but does not limit the invention. EXAMPLE 6 g of hydroxyethylcellulose were dissolved in 800 ml of distilled water with stirring.

Then, 40 g of Na2H2O4H2O4, 40 g of Na2SO4, 20 g of NaOH, 30 g of Na2SO4 are added sequentially. 0.15 g of KBr, 0.16 g of 1-phenyl-5-mercaptotetrazole and 0.16 g of 2-mercaptoimidazoline.

After complete dissolution, the solution was made up to 1000 ml with distilled water and filtered to be used for processing diffuse photo materials with both paper and film substrates.

Claims (2)

OBJECT OF THE INVENTION Activating solution for the treatment of halogen silver diffusion photomaterials consisting of 3.5 to 4.5 wt. microcrystalline solvents, respectively. % of silver halides, 1.9 to 2.1 wt. alkali activating reducing agents, from 5.9 to 6.1 wt. % of a mixture of pH-maintaining substances, 2.95 to 3.15 wt. % of a diffusion rate enhancer, 0.55 to 0.65 wt. hydroxyethylcellulose, characterized in that it contains 0.05 to 0.2 wt. % of 1-phenyl-5-mercaptotetrazole, 0.05 to 0.2 wt. 2-mercaptoimidazoline and the remainder to 100 wt. water.