DE1572091B - Light-sensitive Auskopierendes Ge mix - Google Patents

Description

γ Y are too expensive.

In the case of the blueprint papers, the resulting

2 CR ₁ or ZCR ₁ images have excellent stability, the material

j>'\ // lien have the disadvantage of a bad one

"N © 15 tint quality, low sensitivity and good

I struggle with resolving power.

₂ . χΘ R ₂ χ © For recording materials that are photolytic

Contain halogen-containing compounds, where R _{1 is} an alkyl group with 1 to 3 carbon atoms on difficulties that the used or an aralkyl group, R _{2 is} an alkyl group with 20 photoactivatable components toxic and volatile 1 to 4 carbon atoms or an aralkyl group, X are one and that therefore increased attention is required with the anionic group, Y a - Se -, - S -, handling of photosensitive papers containing - O - -, - N - alkyl - or - CH = CH - these mixtures .
Group and Z to close a hetero-object of the invention is to create a new record

cyclic, optionally substituted ring 25 indicate material that is cheap and easy mean required atoms and can be handled as a color former and have clear and stable colors aromatically substituted nitrile, provides images with high resolution,

a nitroso compound, the subject invention proceeds from one

an aromatic aldehyde, photosensitive, copying mixture that consists of

an aromatic amine, 3 ° a photosensitive compound, which at the one Phenyl ketone, reacting to light, and from one

an aromatic ketone, color former, and is characterized by

a heterocyclic substituted ketone, characterizes that it is a photosensitive compound

Acetanilide, heterocyclic quaternary salt of the formulas

Diphenylguanidine, 35γγ

Phenazine,

Hexamethylenetetramine, ZC - R ₁ or ZC - R ₁

N-vinylcarbazole, '·, y \ y

Indole, ^% C 'f

Phenyl diethanolamine, 40

Diurea or a hydrazide of an aromatic η ve π

Contains carboxylic acid. ^{2 2}

wherein R _{1 is} an alkyl group with 1 to 3 carbon atoms or an aralkyl group, R _{2 is} an alkyl group with 1 to 4

45 carbon atoms or an aralkyl group, X an anionic group

Group, Y one - Se -, - S -, - O -, - N - Alkyl or - CH = CH - group and Z the to

The invention relates to a light-sensitive exclusion of a heterocyclic, optionally sub-copying mixture, the atoms required from a light-sensitive substituted ring, and a compound which reacts as a color former when exposed to light
tion is capable, and consists of a color former. an aromatically substituted nitrile,

As a so-called copying recording material - a nitroso compound,
materials which, when exposed to light, form an aromatic aldehyde,
are known to date: an aromatic amine,

55 a phenyl ketone,

1.Silver copy paper, which is a light-sensitive - an aromatic ketone,

Lich silver salt as a photosensitive component a heterocyclically substituted ketone,
contain. Acetanilide,

2. Blueprint papers containing a light-sensitive iron diphenylguanidine,
contain salt as a photosensitive component. 60 phenazine,

3. Photosensitive mixtures, the photolytic hexamethylenetetramine,
contain organic halogen compounds, such as N-vinylcarbazole,

they in U.S. Patent 3,042,515-9 be indole,

are written, and phenyldiethanolamine,

4. Photosensitive mixtures, which are used as photosensitive 65 diurea or a hydrazide of an aromatic Liehe component contains a leukocyanide of a tricarboxylic acid.

contain phenylmethane dye, as they are in the light-sensitive Aus-USA.-Patent 2,676,887. Mixtures delivering copy images are available that

3 4

the disadvantages of the known photosensitive heterocyclic compounds develop themselves

mix do not exhibit. the action of light is not a color, but becomes

Thus, the photosensitive elements according to the invention contain an active substance due to the action of light

lent mixtures no toxic components and are brought to state with strong reactivity and

therefore easy to use. The resulting images 5 react with the color formers to develop

are not only in terms of the tint quality of a colored record, whereby dyes are formed

peaceful and show an excellent resolution from which the images are built,

ability, but also have an excellent The latter in the present invention

Stability on. Using the light-sensitive in combination with the photoactivatable components

Lichen mixture of the present invention obtained io components, the first-mentioned ingredients, use-

The components developed in the copying-out recording material are color formers. The color formers

directly a colored record if there is one developing itself under the action of light

Irradiation, for example, with ultraviolet or, like the photoactivatable compounds, none

exposed to visible light. Therefore it is pos- sible to have colored records, but develop colored ones

Jich got a clear picture, then through a 15 records only through implementation with the through

subsequent fixation step to a stable the action of light photoactivated compo-

Image can be fixed. components that are brought into a reactive state

Both of the above-mentioned components that have been incorporated into. The suitability of the connections as color

The component forming photosensitive mixtures according to the invention can be determined by

are kept, non-toxic and stable substances 20 are the component along with about the same

and are readily available, so that the amount of a selected photoactivatable compound obtained therefrom

Recording material not only safe with the hand component (for example 2-methylbenzthiazol-methyl-

but also has an excellent shelf life and iodide) is dissolved, the solution as a layer on a paper

can be manufactured at low cost. applied and then the paper after drying

The following is a detailed description of the present invention to which light is exposed.

Jierter explains. The first-mentioned examples according to the invention for suitable photoactivatable compounds

The components used are photoactivatable grain fertilizers with nitrile groups are compounds such as

components that under the action of light in a p-nitrobenzonitrile, benzoylacetonitrile, p-nitrobenzyl

Cyanide and p-aminobenzoylacetonitrile can be brought into a reactive state.

and the general 30 examples of suitable compounds with carbonyl-

Formulas are reproduced. Examples of such groups are benzyl acetone, ρ, ρ'-tetramethylamino-

Photoactivatable components are 2-methylbenz- benzophenone, benzophenone, phenylbenzyl ketone, 3-Py-

thiazolmethyl iodide, 2-methylbenzthiazol-ethyl iodide, ridyl-4-quinolyl ketone, / I-naphthoquinone, benzoquinone,

2-methylbenzthiazole-n-butyl iodide, 2-methylbenzthia-anthraquinone and phenanthraquinone.

zol-ethyl-p-toluenesulfonate, 2-methylbenzthiazol-ben- 35 examples of suitable compounds with aldehyde

zyl bromide, 2 - methylbenzthiazole - ethyl - fluoroborate, groups are o-phthalaldehyde, o-phthalaldehyde,

2-methylbenzthiazol-propionic acid bromide, 2-methyl-2,4-dihydroxybenzaldehyde, terephthalaldehyde acid,

5-chlorobenzothiazole-ethyl-p-toluenesulfonate, 2-methyl- 3-hydroxy-4-methoxybenzaldehyde, / S-naphthoaldehyde

6 - ethylbenzthiazole - methyl iodide, 2,6 - dimethylbenzaldehyde, oc-naphthoaldehyde, 2,4-dichlorobenzaldehyde,

thiazole ethyl fluorate, 2-methyl-6-ethoxybenzthia- 40 p-nitrobenzaldehyde, salicylaldehyde, p-hydroxy-

zol-propyl bromide, 2-methyl-5,6-diethoxybenzthiazol benzaldehyde, m-nitrobenzaldehyde, o-nitrobenzaldehyde

propyl bromide, 2,5,6 - trimethylbenzthiazole - ethylhyd and 5-bromosalicylaldehyde.

p-toluenesulfonate, 2-methylnaphthothiazole-ethyl-fluo- Examples of suitable compounds with nitroso-

borate, 2,4,5-trimethylthiazole-ethyl-fluoborate, 2-Me groups are N-nitrosodiphenylamine, phenyl-2-naph-

thyl-4,5-diphenylthiazole-methyl iodide, 2-methylbenzo- 45 thylnitrosamine, sodium-l-nitroso-2-naphthol-3,6-di-

selenazole ethyl bromide, 2,5 - dimethylbenzoselenazole sulfonate.

n-butyl iodide, 2-methyl-5-ethoxybenzoselenazole-ethyl examples of suitable compounds with amino

p - toluenesulfonate, 2-methylnaphthoselenazole-ethyl groups and nitrogen-containing compounds

ρ - toluenesulfonate, 2 - methyl - 5 - methoxybenzoxazole / 3-naphthylamine, acetanilide, diphenylguanidine, phena-

ethyl iodide, _ 2-methyl-5-phenylbenzoxazole-ethylbroine, hexamethylenetetramine, diphenylamine, vinylcarb-

mid, N - ethyl - 2 - methyl - 5,6 - dichlorobenzimidazole azole, indole, phenyldiethanolamine, tetramethyldi

methyl iodide, 2-methylpyridine ethyl iodide, 2-methylamino-diphenylmethane, N, N'-diphenyl-p-phenylene-

pyridine-methyl iodide, 2-methylpyridine-methyl-p-toliiol diamine, diurea, salicylidene-p-toluidine, o-nitro

sulfonate, 2 - Methylchinolinmethyljodid, 2 - methyl benzal -SS- naphthylamine, salicylidene - ο - chloroaniline,

quinoline ethyl iodide, 2-ethylbenzthiazole ethyl iodide, 55 salicylidene aniline, ο - nitrobenzalisonicotinic acid hydra-

2 - benzylbenzthiazole - methyl iodide, 2 - phenethylbenzide, salicylidene-ß-naphthylamine, p-anisalphenylhy-

thiazole-ethyl iodide, 2-methyl-benzthiazole-n-butyrodrazide, salicylidene-o-anisidine, benzalphenylhydrazide,

sulton, 2,5,6 - trimethylbenzthiazole - η - butyrolactone, ο - nitrobenzal - p '- anisidine, ο - nitrobenzal - ρ - nitro-

2-methylbenzthiazol-ethylsultone, 2-methyl-5-ethoxy-aniline, salicylidene-p'-bromaniline and m-bromosalicy-

benzoselenazole-n-butyrosultone, 2-methyl-benzthiazole- 60 hdenbenzylideneamine.

n-butyrosultone, 2-methyl-benzthiazol-ethylsultone and the sensitivity of light-sensitive mixtures

2-methyl-5-ethoxy-benzselenazole-n-butyrosultone. and the hues obtained in each case change to

In addition to the compounds mentioned there is dependence on the combination of photoaktinoch many effective compounds under the all-four component and the color former. Example mean Formula fall with what the present 65 are the developed color tones and the wise Invention usable photoactivatable compo- sensitivities of copy-out materials that are not limited to the above examples. using o-phthalaldehyde acid (OPA) The compounds used as photoactivatable and diphenylamine (DPA) as color-forming components

components with various photoactivatable components were prepared, as in the following Table shown. The photographic sensitivities of the photosensitive compositions are determined by the Expressed the number of steps of wedges that are copied out when the substances in a given light source be suspended by step wedges with a step difference of 5.08 mm.

Photoactivatable component GRANDPA DPA 2-methylbenzthiazole
methyl p-toluenesulfonate Purple
8 levels Light brown
5 levels 2-methyl-5-chlorobenzthia-
zol-ethyl-p-toluenesulfonate Brown
12 levels Light brown
6 levels 2-methylnaphthothiazole
ethyl p-toluenesulfonate green
12 levels blue
8 levels 2,5-dimethylbenzthiazole
methyl fluoborate Purple
13 levels reddish
purple
15 steps 2-methylbenzthiazole
propionic acid bromide bluish
purple
13 levels reddish
purple
13 levels 2-methyl-6-ethoxybenz-
thiazolpropyl bromide blue
15 steps Brown
9 levels 2-methylbenzthiazole
ethyl iodide Purple
13 levels blue
11 levels 2-methylbenzoselenazole
ethyl iodide blue
10 levels blue
8 levels 2,5-dimethylbenzoselene
azole butyl iodide blue
14 steps blue
9 levels

Other components, such as sensitizers and heat setting accelerators, can, if necessary to be incorporated into this mixture in order to improve the properties of the resulting copy-out materials to improve further. There are two types of sensitizers, one of which is photographic General sensitivity of the present photosensitive printout compositions themselves' increase while the others increase the spectral sensitivity. As a sensitizer of the first type, organic and inorganic metal salts and ammonium salts are effective. Examples for this are sodium chloride, calcium chloride, potassium bromide, sodium fluoride, aluminum fluoride, zinc fluoride, Barium fluoride, sodium sulfate, zinc lactate, lead stearate, the sodium salt of pyruvic acid, sodium hypophosphite, Ammonium rhodanate and ammonium citrate. In addition, heterocyclic compounds are also such as benzthiazole, benzoxazole, pyridine and quinoline are effective. In addition, if white pigments, such as titanium white, zinc oxide or aluminum oxide powder are used, these pigments absorb the coloring substances formed, the developed color density apparently increasing the sensitivity increases. White pigments, for example, have the same effects as sensitizers. The sensitizer dyes known in photographs are effective as spectral sensitizers, including compounds of the cyanine, xanthene and acridine series. Examples are pinacyanol, Pinacryptol Yellow, Eosin, Iodeosin, Rose Bengal, Auramine, Thioflavin-T, Erythrocin-B, Bromthymol-Blue and acridine orange. With the proper use of these sensitizers, the sensitivities the copying produced with the photosensitive mixtures according to the invention Recording materials can be increased up to about 10 times, and using these sensitizers produced copy-out recording materials are not only resistant to ultraviolet rays sensitive, but also to

ίο visible rays. Therefore, it also becomes possible to obtain enlarged images by copying a photographic negative using an incandescent lamp as a light source.
Other components that are desirably incorporated into the present printout photosensitive compositions are heat set accelerators. Copy-out images produced from the present copy-out compositions are fixed after copying by subjecting them to a heat treatment, generally using a hot roller, and are thereby fixed against further exposure to light. In this case, the addition of weak reducing compounds such as nitrites, sulfites, hydrazines and hydroxylamines makes it possible to improve the heat-setting property and also the stability of the resulting images.

A copy-out recording material is preferably produced by the constituents of the Mixture dissolved in a suitable solvent or finely dispersed in a suitable binder and by applying the solution or dispersion as a layer to a layer support and is then dried. A print-out material with improved physical properties can generally obtained when the binder is a film-forming substance of high molecular weight which is soluble in the coating mixture is used. To such connections with high Molecular weights useful as water soluble binders include polyvinyl alcohol, carboxymethyl cellulose, Hydroxyethyl cellulose and maleic anhydride copolymers, while compounds which are suitable for use in organic solvents, cellulose derivatives such as cellulose acetate, Cellulose acetate butyrate and ethyl cellulose, vinyl polymers or copolymers of vinyl chloride, Vinylidene chloride, vinyl acetate, acrylic ester and styrene, maleic anhydride copolymers and synthetic rubbers such as cyclized rubber, acrylic rubber, and butadiene copolymers. Usable solvents include, in addition to water, alcohols such as methanol, ethanol and propanol; Ketones such as acetone and methyl ethyl ketone; Hydrocarbons such as benzene, toluene, xylene, hexane and ligroin; halogenated hydrocarbons such as methylene chloride and trichlorethylene; and esters, like Ethyl acetate and amyl acetate. In addition, tetrahydrofuran, dimethylformamide and cyclohexanone can be used be used. These can also be in the form of mixed solvents such as hydrous Methanol and acetone / methanol can be used. Suitable support on which the present copy-out compositions to be applied are generally papers such as photographic Papers, plastic-coated papers and copy papers. However, cellulose acetate films or are also made of polyethylene terephthalate and polycarbonate

7 8

preferred plastic sheeting. Furthermore, you can also use the copy-out material after the copy Glass foils or metal foils are used, ren is immersed in a solvent that the what depends on the purpose. Coloring substances formed by exposure The application of the present photosensitive does not dissolve, however, the imparted in the unexposed parts Copy-out compositions on the layer- 5 remaining components dissolve.

The carrier is placed in a dark place according to the known methods carried out for this purpose. Material that comes from a light-sensitive copy instead The print-out materials are made by coating composition, the 2-methylbenzvon Supports with the thiazol-methyl-p-toluenesulfonate and diethylamine ent-manner indicated above The resulting coating mixtures can be prepared with acetone, methyl can However, the copy-out materials can also be solvent-fixed in ethyl ketone or ethyl acetate. special cases can be prepared by the respective- The use of a solvent of the alcohol gene Components ranked in the form of fine particles is undesirable because the resulting coloring brings, these finely divided particles are mixed and the substances are dissolved out. The solvent itself The resulting mixture on the surface of a 15 fixation does not always make the application of the organic support is rubbed on, whereby a polishing shear solvent is necessary, but it can also roller is used, or by placing the components in water or in aqueous solutions, the appropriate contain inorganic salts in the paper material during the sizing treatment, can be incorporated. Coating mixtures for thermal fixation or solvent production the photosensitive printout-mate- 20 fixing in the above manner subjected images In general, materials can be stable to light and retain clear color structures as follows be: tints without discoloration, even if they are several

Exposure to direct sunlight for several days.

Solvent 1000 The following examples are intended to enhance the present invention

Binders (if applicable) .. 5 to 300 25 further illustrate without limiting them,

photoactivatable component 10 to 100. -I ₁

color-forming component .... 10 to 100 B e 1 s ρ 1 e 1 1

Sensitizer (given 40 g of 2-methyl-5-ethoxybenzoselenazole-p-toluene-sul-

otherwise) 0.1 to 10 fonat as photoactivatable component and 60 g

Heat setting accelerator 30 o-phthalaldehyde acid as a color former are used in

5 to 200 ml of water (optionally) in a dark room to form

a photosensitive mixture dissolved. That so

When the mixture obtained using the above-mentioned is applied by a conventional method, photosensitive print-out compositions of the print-out materials obtained as a layer on an ordinary photographic present invention base paper having a thickness of 45 g / m ² emit ultraviolet rays or visible rays - and are placed in a dark place at a temperature under, develop immediately clear 60 ° C dried, whereby a copy-out material receives colors that give images when imagewise exposed. will. This copy-out material is in contact. For the exposure, a photographic negative for 5 seconds commercially available copier for photosensitive 40 a SOO-W high pressure mercury lamp made of a diazo-type paper, in which a mercury removal of 3 cm exposed, with the copying silver lamp or a fluorescent lamp as the light material immediately develops color and a source is used. If a deep blue-green, clear positive image on a white background is desired, the exposure according to the reflex copy results. Since the unexposed portions of the material pass under ren, a copier for exposure to light can develop color when diffusion transfer copying is used. Material is left untreated, the image addition are fixed from the present composi- by the material made between hot drum tongues with sensitizing dye en rolls having a surface temperature of 160 ⁰ C sensitized print-out materials from considerably is passed. This fixing treatment results in high sensitivity and, therefore, a stable image which does not discolor even large copies of photographic negatives when exposed directly to sunlight can be obtained. Which are obtained with an enlarger, the maximum density of the image is 1.40, and which or a light image projector is used. The veil blackening is 0.02. The image obtained from the exposed print-out materials remain light-sensitive - it is a positive image which, if left untreated, reproduces the tint of the original and therefore faithfully reproduces the negative,
it is necessary to freeze the images in order to make them. .
become stable. This fixation is used in the general example
The easiest way is by thermal treatment by 50 g of 2-methylbenzthiazole-methyl iodide as photo-guided. The thermal fixation is easily activated by the component and 50 g of N-nitrosodiphe carried out by the copying-out materials between 60 nylamin as a color former are dissolved in 1000 ml of a hot roller with a surface temperature of acetone / methanol mixture 1: 1, with a about 100 to 18O ⁰ C are passed. In addition, a photosensitive copy-out mixture can be obtained, the material can be placed between hot plates. The fixation 65 cal barium oxide paper is applied and can be dried not only by heating, but also by producing a copy-out material. Treatment carried out with a solvent. This print-out material develops when it is exposed. The solvent treatment is carried out immediately with a mercury vapor lamp

9 10

Color, whereby a deep green image is passed on to a white surface temperature of 14O ⁰ C, whereby

Background results. The image is then fixed by obtaining a positive microfilm with good resolution

it is washed with water, becoming a stable one suitable for projection. If that

Image is obtained. Copy-out recording material in connection

The above procedures are repeated, denoted by 5 with a halftone photographic negative

except that the photoactivatable component is subjected to copying programs, a clear one

due to the same amount of 2-phenethylbenzothiazole - transparent positive with excellent tinting

methyl iodide is replaced. For this photosensitive quality obtained. The material of this example is

Mixture, a copy-out material is produced, which continues to be used as an intermediate original for the diazo copier

with the same treatment as above, a clear and OK procedure is suitable.

gives a stable brown image on a white background. _, .., "■

Example 5

^Example 50 g of 2-methylbenzthiazole methyl iodide are used in

A photosensitive mixture is applied to a 1000 ml of a 3 percent aqueous gelatin solution

dark place according to the following formulation. To the solution 50 g of benzophenone and

put: 30 g of aluminum oxide powder and the mixture

2-Methylbenzthiazol-äthylfiuoborat 20 g ^is ground 2, ° rounds in a ball mill, whereby

Benzoylacetonitrile 30 g ^eme l ^lcntem pfi ⁿ lethal print-out composition

Cellulose acetate butyral ......... 15 g is obtained, which is a microfine dispersion.

Methanol 500 ml ²⁰ ^ ^{as so obtained} photosensitive mixture is used as

Ethyl acetate '500 ml layer in a dark place according to a usual

". Process on barium oxide photographic paper

The photosensitive mixture thus produced is applied. After drying, an eco-

obtained as a layer with a thickness of 20 ml / m ² on a photographic recording material. This

barium oxide graphic paper with a thickness of 25 print-out material is produced using a

150 g / m ² applied and then dried, using a mercury vapor lamp for copying,

a copy-out recording material was obtained, the material immediately being a clear brown

will. When the print-out material is developed using image on a white background. This picture can

a mercury lamp used for copying by fixing with hot rollers to a stable one

color develops immediately, whereby 30 images are made,
a clear purple image on a white background

results. The recording material has about twice the size

Sensitivity of a commercially available light _A , ,, ^,. ,,,.,.

sensitive paper of the dry diazo type. That in a dark place, two river _lg speeds A

Image is made after copying by washing with 35 and B according to the following formulation:

Ethyl acetate fixed, forming a stable image with. .

high resolution results. Liquid A

The above procedures are repeated with 2-methylbenzthiazole methyl iodide ... 40 g

the exception that instead of the color-forming sodium fluoride 40 g

Component used benzoylacetonitrile the 40 water 600 ml

the same amount of salicylidene-yS-naphthylamine for the production of copied recording material liquid B
is turned. The recording ..

material provides a clear o-phthalaldehyde acid on imagewise exposure ..... 30 g

yellowish-brown image with good resolution on a white 45 acndin orange (2 percent metha-

Basic solution) 5 ml

'' Water 400 ml

Example 4

A photosensitive mixture is applied to one. The two liquids are mixed, being one

50 light-sensitive mixture is obtained in a dark place according to the following formulation. The light-sensitive mixture produced in this way is used as a layer of 2-phenethylbenzthiazole-methyl iodide 50 g ^η ^ ^Κ « ^ne . ^{In the} usual method applied to a photographic Diphenvlamin 50 2 cal barium oxide paper, this is then dried methyl vinyl ether-Maieinsäureanhy- 'with a copying recording

drid copolymer 15 g of ^{55 material is} obtained. This copy-out material has

Acetone _ 300 ml has a high sensitivity as it sensitizes

Methanol 700 ml ^the dye together with the sensitizing agent

medium contains sodium fluoride. This recording

The photosensitive mixture produced in this way can therefore already be used when using provide print-out images as a layer in a dark place after a usual visible light. Under Ver Proceedings on a cellulose triacetate layer support turning a microfilm image as a master copy and upset. After drying, a 300 W projector will produce a positive clear image received piercing recording material. With Beiich- with 50x magnification on the Auskopiermatetung by means of a microfilm negative is obtained under verrial. When the material between hot grove a mercury vapor lamp directly color 65 zen with a surface temperature of 160 ° C and a brown-colored image is passed on to the transparent, an image is fixed that is not ver-layered generated. The image is fixed by tinting it even when it is exposed to direct sunlight Recording material by hot rollers with a and that shows good resolution.

11 12

Example 7 The _{mixture obtained in this way} is according to a customary

A photosensitive mixture is applied to a chen method as a layer with a layer application

dark place prepared according to the following formulation: from 25 ml / m ² on a plastic-coated paper

2-methylbenzoselenazole-n-butyl iodide applied 20 g, the surface treatment with

p-nitrobenzaldehyde has been subjected to 30 g of 5 polyvinyl alcohol, and will

Polyvinyl acetate 20 g then dried, with a copying-out ethyl acetate 100 ml of drawing material is obtained.

Claims (1)

1 2 From the German Auslegeschriften 1 134 587 and Claim: 1172115 are still light-sensitive copies known mixtures that consist of a photoactivating Light-sensitive copying mixture, the free compound and consist of a color former, from a light-sensitive compound, which at 5 The known copying materials have becomes reactive to the action of light, and has disadvantages in various respects. That's how they are consists of a color former, the resulting images are often unstable and different indicates that there is a photosensitive difficulty in handling the recording compound a heterocyclic quaternary salt of the voltage materials, or they are too low Formulas io sensitivity to or the resulting images