Title:
Photographic developer
United States Patent 2017167


Abstract:
This invention relates to photographic developers, and more particularly to developers in which the usual alkalies are replaced by a compound new for the purpose. Alkaline developers have been known and used for many years. These developers usually contain developing agents, a so-called preservative,...



Inventors:
Russell, Harold D.
Application Number:
US73795834A
Publication Date:
10/15/1935
Filing Date:
08/01/1934
Assignee:
EASTMAN KODAK CO
Primary Class:
Other Classes:
430/482
International Classes:
G03C5/305
View Patent Images:



Description:

This invention relates to photographic developers, and more particularly to developers in which the usual alkalies are replaced by a compound new for the purpose.

Alkaline developers have been known and used for many years. These developers usually contain developing agents, a so-called preservative, such as sodium sulfite, and an alkali, such as sodium or potassium carbonate, or sodium or potassium hydroxide. In recent years various sensitive materials and photographic processes have appeared with which the use of these relatively strong alkalies is objectionable for one reason or another. One object of this invention is to provide developers containing a milder alkali. Another. object is to provide developers which will give satisfactory results without the objectionable features of those containing the alkalies previously used, such as the formation of gas blisters when a film developed in a developer containing carbonate is immersed in an acid fixing bath.

I have discovered that by using a sodium salt of triethanolamine as the alkaline component, developers may be prepared which fulfill all these objects.

The sodium salts of triethanolamine may be prepared by, dissolving powdered sodium hydroxide in triethanolamine, with heating. The amount of sodium hydroxide used is one, two or three equivalent weights, depending upon whether the mono-, di- or tri-sodium salt of triethanolamine is desired. The three salts, or mixtures thereof, may be used interchangeably in devel-. oper formulae.

Suitable developer formule embodying my invention are given here, by way of example.

EXAMPLE 1 Hydroquinone ------------------ 10 grams Sodium sulfite----- -----..--..- 10 do.

Potassium bromide ...--- -------. 5 do.

Sodium salt of triethanolamine....-- 50 do. 45 Water to make --------------- 1 liter EXAMPLE 2 Two-BATH FOBMULA Bath No. 1 Elon -----.. --------------------- 5 Hydroquinone.------------------ 10 Sodium sulflte------- ---------- 100 Sodium bisulfite- ......------------. 5 55 Water to make ---------------- 1 grams do.

do.

do.

liter Sodium sulflte-.------------------ 10 grams Sodium salt of triethanolamine....-- 50 do.

Water to make--------------- - 1 liter The film or plate is first immersed in Bath No. 1 for 2 to 3 minutes and then in Bath No. 2 until development is complete.

EXnAMuPLEi a Elon ------------------------- 5 Hydroquinone---------------- 10 Sodiuim sulfte---------------- 75 Sodium salt of triethanolamine --- 50 Potassium bromide ------------Potassium iodide-----.. -------- 0.01 Water to make------------------- 1 EXAMPLE 4 Elon --------- --------------Hydroquinone -----------------Sodium sulflte --.---....-----.. Sodium salt of triethanolamine.--. Potassium bromide.-----------Potassium iodide---------------Water to make -----------------10 75 20 5 0.01 1 grams do.

do.

do.

do.

grams 20 do.

do.

do.

do.

do. 2e liter The above examples show the sodium salt of triethanolamine as the sole alkaline component of the developer. I have found, however, that mixtures of a sodium salt of triethanolamlne 30 with other alkalies are advantageous for some purposes. For example, I may use a mixture of caustic soda, borax, and a sodium salt of triethanolamine. Or I may use a mixture of sodium metaborate and a sodium salt of triethanol- 35 amine. Following is an example of a developer in which such a mixture of alkalies is used.

EXAMPLE 5 Eon ----------------------------- 2 Hydroqulnone -----------.---------- 5 Sodium sulfite ------------------ 50 Sodium metaborate ------------- 30 Sodium salt of triethanolamine--- --- 10 Potassium bromide ------------ 2 Water to make------------------ 1 grams40 do.

do.

do.

do.

do.

liter It will be understood that I am not to be limited by the above examples except as indicated in the appended claims. 50 While I have spoken of the sodium salts of triethanolamine, it will be apparent that I may also use the potassium or other alkali metal salts of triethanolamine.

What I claim as my invention and desire to 55 -be secured by Letters Patent of the United States is: 1. A photographic developer comprising a developing agent and, as an essential alkaline-reacting component of the developer, an alkali metal salt. of triethanolamine.

2. A photographic developer comprising a developing agent and, as an essential alkaline-reacting component of the developer, a sodium salt of triethanolamine.

3. A photographic developer comprising a developing agent and an alkali, at least 25%, approximately, of the alkali consisting of an alkali metal salt of triethanolamine.

4. A photographic developer comprising a developing agent and an alkali, at least 25%, approximately, of the alkali consisting of a sodium salt of triethanolamine.