DE1009020B - Process for sensitizing halide silver emulsions - Google Patents

Description

GERMAN

As is known, the halide silver emulsions show an inherent sensitivity in the spectral violet. Particularly in the case of chlorosilver emulsions, only a small part of the sensitivity is in the visible range of the Light, while the main sensitivity is in the ultraviolet. In practical use, now the effect of the glass cut off by far the greatest part of this sensitivity. This affects especially when working with artificial light because of its short-wave spectral component is very low. So in the photographic copying process only a small part of it is used of the coming light.

It is now known that the addition of dyes opens up a new range of sensitivity can add to the photographic emulsion for visible light and thus a better light yield, d. H. a higher overall sensitivity is achieved.

However, there is a serious disadvantage that for processing in the darkroom only a smaller part of the spectral spectrum of visible light is available, because you have the Must switch off rays to which the photographic layer has additionally been made sensitive. So you have to use a physiologically darker light for the darkroom lighting; but this makes it much more difficult to assess the image that appears during development, which is particularly uncomfortable when the picture is positive, ζ. B. a paper image is. Indeed In practice, these images are best made with the physiologically very bright yellow light, such as the Agfa darkroom filter 112, manufactured in which a good assessment of the resulting image on the correct gradation and blackening is possible. Of course it would be possible, for example a pure one To use chlorine silver emulsion, which can then be easily processed in bright yellow light can. But you get relatively long exposure times, especially with hard-working people Layers. Sensitization of this chlorosilver emulsion results in an increase in sensitivity and thus the desired reduction in copying time. At the same time, however, the sensitivity to the yellow darkroom light is increased in an undesirable manner, so that also partial exposures occur that appear as a change in gradation or even as a haze.

It has now been found that you can increase the sensitivity of the halogen silver emulsions without Deterioration of darkroom safety can occur if Neutrocyanine to sensitize following general formula

Process for raising awareness
of halogen silver emulsions

Applicant:
Agfa Aktiengesellschaft

for photofabrication,
Leverkus en-B ayerwerk

Dr. Oskar Riester, Leverkusen,
has been named as the inventor

\ /
- ^x c =

R ₁ N

OC

be used.

In this formula, R ₁ denotes alkyl, aralkyl, aryl, acyl, acyl ester, alkyl sulfonic acid and other groups; R ₂ and R ₃ are identical or different and represent hydrogen atoms, alkyl, aralkyl, aryl groups or a heterocycle without nitrogen, where R ₁ and R ₃ or R ₂ and R ₃ can be linked in a ring; η is an integer from 3 to 12; Z and Y are NH, NR groups, where R has the same meaning as R ₁ , or oxygen, sulfur or selenium atoms, where Z and Y are identically or differently substituted and connected to one another by a ring closure. Ring systems of this type are, for example, thiohydantoin, rhodanine, isorhodanine, selenorhodanine, oxythionaphthene, indanedione, pyrazolone.

The whole dye molecule can also be multiplied, for example by adding the ring nitrogen atoms linked to each other through a divalent organic residue such as an alkylene group are.

The production of these neutrocyanins takes place according to the process of the German patent 927 043.

709 510/356

The dyes result in particular in photographic emulsions which are predominantly from Chlorine silver exist, sensitivity increases up to about ten times the intrinsic sensitivity and nevertheless allow safe processing in light yellow light. A major benefit of this Sensitizers consists in the fact that when they are used, completely uncolored layers after processing remain, while otherwise with good sensitizers often a so-called residual color in the Gelatine or in the barite layer remains, which has a yellowish tint similar to a yellow haze affects.

Another advantage is their resistance to the usual emulsion additives, such as Stabilizers, wetting agents, fluorescent substances, etc.

The sensitizers are added e.g. B. in amounts of 3 to 100 mg depending on the desired Increase in sensitivity. It can take place at any time, e.g. B. as a casting additive for finished emulsion or already during the Nachdigestion, or the sensitizers are in the so-called Bathing method applied.

Example 1 The yellow dye of the following constitution H,

C = C

O = C

C = S

C _R H _S

C ₂ H ₅

results in an increase of 5 to of ache, and that Sensitization maximum is 442 ηαμ.

Example 4 The dye of the following constitution

CH,

H ₉ C

HX.

CH,

C = S

O = C

CH,

CH,

Se

C ₂ H ₅

H ₂ C

H ₂ C

C = C

OC

results in an increase of the ofache in the output sensitivity a steep chlorosilver emulsion with the addition of 30 mg to 1 kg of emulsion; the sensitization maximum is 434 ηιμ.

C ₄ H ₉

Example 5

40

shows a sensitization maximum at about 454 μm and an increase in the sensitivity of a chlorosilver emulsion containing about 2% iodide of silver to the 1 fold.

H ₂ H ₂
C — C,

X — C '

XIo Xlo

Hn Ho

X = C

Example 2 The pale yellow dye of the following constitution

H ₂
C.

CH,

C ₂ H ₅

The increase is ofache; the sensitization maximum is at 436 ιημ,

Example 6

H ₂

H ₂ C

H ₂ C

CH,

C = C

C = S

NO = C

CH,

C, H _s

55

60

gives an increase in sensitivity of about 7 times for a medium-part chlorosilver emulsion; Sensitization maximum at about 434 ηιμ.

Example 3 The dye of the following constitution

N H/
γ H ₂ C S. /
CH CH ₂ 2 CH ₃ C =
O = HC
/ \ \
ζ
/ I.
CH ₂ C = S H ₂
c Cp / H ₂ C
\ /
C.
C.
\ H ₅ \ /
N C ₀

The increase is 7 to 8 times; the sensitization maximum is 456 ΐημ. Example 9 A dye of the constitution

Example 7

The dye

H ₂ C

H, C

CH,

H ₂ CH ₂ C
H, C

C = C O = C

C = S

NC ₄ H ₉

C ₉ H ₅

CH ₂

CH ₂

C = C O = C

C = S

NC ₂ H ₅

increases the sensitivity of a chlorosilver emulsion 6 to 7 times; the sensitization _{maximum ao} is 436 ηιμ.

Example 8 The dye of the following constitution H ₉ C

H ₂ C

C = C O = C

C = S

CH ₂

CH,

C ₂ H ₆

H ₂ C

H ₂ C

N
(CH ₂ ) O

H ₂ CC =

I.

H "C CH

C = C O = C

C = S

dissolved in acetone-methylpyrrolidone 1: 1, gives a Increase of 9 times with a very steep chlorosilver emulsion; the sensitization maximum is at 442 ιημ.

Example A dye of the constitution

H ₂
C.

C = S

O = C H ₂ C
H ₂ C

C = C O = C

C = S

C ₂ H ₆

45 N.
CH,

C ₂ H ₆

is dissolved in methylpyrrolidone 1: 1000 and one

Chlorine silver emulsion added before pouring. This gives an increase in a chlorine silver emulsion

The increase in sensitivity is 6 to 7 times; 50 to 3 to 4 times; the sensitization maximum

the sensitization maximum is 439 πιμ. is 430 ηιμ.

example

A dye of the constitution

H ₂ C.

H ₂ C

HX

C = C O = C

C ₂ H ₆

N CH,

C = S S = C

CH,

/ H ₂ C

C = C

\

C = O N

C ₂ H ₆

CH ₂

CH,

results in a 9-fold increase in a chlorosilver emulsion; the sensitization maximum is 440 πιμ.

Claims (3)

Patent claims: 1. Process for sensitizing halogen silver emulsions, characterized in that one neutrocyanine of the general formula (H ₂ C) _n R ₃ R ₁ N OC "Υ- used, wherein R _{1 is} an alkyl, aralkyl, aryl, acyl, acyl ester, alkylsulfonic acid or similar groups, R ₂ = R ₃ or different therefrom and is a hydrogen atom, an alkyl, aralkyl, aryl group or a Heterocycle without Represents nitrogen, where R ₁ and R ₃ or R ₂ and R ₃ can be linked in a ring, η is an integer from 3 to 12, Z and Y represent NH, NR groups, where R has the same meaning as R ₁ , or oxygen, sulfur or selenium atoms, where Z and Y are identically or differently substituted and are linked to one another by a ring closure. 2. The method according to claim 1, characterized in that neutrocyanines are used, the ring systems thiohydantoin, rhodanine, isorhodanine, selenorhodanine, oxythionaphthene, Contain indandione, pyrazolone. 3. The method according to claim 1 or 2, characterized in that neutrocyanines are used whose dye molecule is multiplied by the ring nitrogen atoms passing through each other an alkylene group are connected. © 709 510/356 5.57