US2162765A - Nonoxidizing and nondeteriorating developer for off-set or contrast film and plate negatives - Google Patents

Description

Patented June 2o,1939f s UNITED, S TE NONOXIDIZING AND NONDETEBIORATING DEVELOPER FOR OFF-SET OR CONTRAST FILM PIATENEGATFYES Louis Tarnofl, Chicago, Ill.-

v No Drawing.

Applicaticn Qctober 28,- 1937, Serial No. 171,594

4c|s1ms.(c1.ss'-as) composition or solution used indeveloping nega- This invention relates to photographic develop ers and more particularly to non-oxidizing and non-deteriorating photographic developers for. use in developing off-set or contrast film and pla '5 n'egatives.

Qne object of this invention is to providea developer which will not oxidize or deteriorate. An-

other obj'ect is to provide a developerwhich when in solution will not lose any of its developing strength because of exposure to the air. A fur? ther object is to provide a developer which will develop more plate or film negatives per uni quantity of developer.

. Other objects include the provision of a developer which: does not lose strength because of contact with air; has greater developing strength because of its non-oxidizing character; decreases in strength solely because-of the number of negatives developed; gives more definiteness, precisefull bottle to preserve.its properties; requires a shorter time forfdeveloping.

Further objects of this invention include the provision of a developer which: will not injure the film or plate negatives; will not alter the form, size, or shape of the negatives; is'a labor saving and time saving one in use; requires no special ability, upon the part of the user; is easy to handle; is inexpensive.

The foregoing objects have been attained bythe developer hereinafter more clearly described. The developer of this invention is especially useful in developing film and plate negatives for the making of so-called line and half-tone nega-' tives of great contrast for off-set printing, photoengraving and lithography. In this application the -term non-oxidizing will be understood to mean a developer whichis not afiected by the oxygen of the air. Expressing it another way one may say that the oxygen in the air does not destroy, disintegrate, or deteriorate the elements of the developer. Off-set or contrast film or'plate negatives are herein used to distinguish from ordinary film or plate negatives, which latter after developing show the objects photographed by meansof intermediate shades between black and white. The object, herein contemplated, on-

the oft-"set or contrast negatives appears white and the entire background appears black, there being no shades between black and white. There will be only the extremes oi black and white. The contrast between blackand white gives the ob- Ject photographed a clear, definite outline. De- 55 veloper as herein, used has reference to a chemical ne'ss, exactness and clearness; avoids the need .of special light protective -bottles; does not require a tives after the film or plate has been exposed and an image of the object taken. The developer brings to view 'onthe negatives the object photographed by inducing changes in the sensitized negative.

-A preferred example of the developer is comabout the proportions s'et out:

posed of the following chemical elements in" The above mixture is to "be kept in a can in dry powdered form and will last indefinitely. Mixture. The chemical elements in their respective proportions are placed in an absolutely drysealed container (can) and in such state may be marketed. ,The above compound mixture must be' kept in -a container (can) in dry powdered iormgand in such form will last indefinitely.

- Sodium sulphiteJ.-. L ounces 8 Boric acid l do '2 Hydroquinone do 3 Sodium carbonate do -12 .Oxallc acid. 1 grains .'200 Potassium br o 360 Citric acid i do 50 Potassium metabisulphlt do 300 When ready to use, it is to be mixed with one 1) gallon of distilled water at a temperatur'eoi 'zo-ao.r' Compounding for usage.-When ready to be used as developer, the compound mixture should bedissolved in one (1) gallon of distilled water at I a temperature of between '70-80 F- Actual usaga- -Afterthe above compound mixture is dissolved in distilledwater, it may then be p laced and kept'in an open tray during the entire working day and kept in a bottle during the night. It isnot necessary that the bottle be of brown color ,nor, is it necessary that the bottle be filled fully with developer as any air present at top of developer will not "affect it. The following day the same developer may be placed in an open tray and used again; Except for the loss of strength of the developer due solely and only to its depletion because of the number of film and plate negatives developed, the developer will not have lost any of its developing strength due to its'exposure to air during the actual process of film and plate negative developing or any other time.

I am aware that prior to my discovery and at the present time there is in existence a type of an oxidizing developer made for the purpose of developing *ofl-set or contrast film and plate negatives. but. to the best of my. knowledge, there is no developer in existence'that has been manufacturedwhich contains the elements, principles,

and non-oxidizing and non-deteriorating feature as does my developer.

Although a preferred embodiment 'of the invention has been described in connection with the composition in both its dry and solution forms and also in connection' with the manner of using the sameyvariations within the true spirit and scope of the same are to be' determined by the appended claims.

What I claim is: A

1. A non-oxidizing and non-deteriorating cleveloper for ofi-set or contrast film and plate negatives consisting of:

' ounces; boric acid2 ounces; hydroquinone-S negatives consisting of:

sodium sulphiteB ounces; boric acid-2 ounces; hydroquinone-3 ounces; sodium carbonate-12 ounces; oxalic acid-200 grains; potassium bromide360 grains; citric acid50 grains; potassium metabisulphit e 300 grains.

3. A non-oxidizing and non-deteriorating developer for negatives including the following elements in about the proportions named: sodium sulphite8 ounces; boric acid-2 ounces; hydroquinone- 3 ounces; sodium carbonate-12 ounces; oxalic acid200 grains; potassium bromide-360 grains; citric acid-50 grains; and

potassium metabisulphite-300 grains.

4. A non-oxidizing and non-deteriorating developer for negatives including the following elements in about the proportions named: s'odium sulphite8 ounces; boric acid-2 ounces; hydroquinone-3 ounces; sodium carbonate-12 ounces; oxalic acid200 grains; potassium bromide-300 grains; citric acid-50 grains; potassium metabisulphite-300 grains; and about one gallon of distilled water.

LOUIS TARNOFF.