Fine-grain developers

The solvent action of sulfite tends to promote fine-grain development, and some of the commercially used fine-grain developers contain as much as 100 grams of sodium sulfite per liter. Some of these developers contain other solvents as well, e.g., thiocyanates and amines. Any of these solvents should cause some shift to occur in the relative rates of the... 

Kopnwa, B. M. (1975) A comparison of various procedures for fine grain development m electron microscopic radioautography. Histochemistry 44, 201—224... 

Alkaline fixer (8.5-9.5) fine grain developers, baking soda... 

Borax is the mildest common alkali. It finds its widest use in low-contrast and fine-grain developers. Decahydrate is the preferred form. Sodium sulfite, though most often used as a preservative, can also be used as a mild alkali. In Kodak D-23 it serves both purposes. 

A good fine-grain developer is considered to be one that yields fine grain without any serious loss of speed. Fine-grain developers should be compensating, that is, they should prevent the formation of heavy, unprintable deposits in the highlight areas. 

Glycin, used in combination with ppd (Formulas Superfine-Grain Developers DuPont No. 3 Superfine-Grain Developer), makes a fine-grain developer with improved emulsion speed and faster rate of development. Unfortunately, because of the presence of ppd, it still suffers from the unpleasant side effects of high toxicity and staining. 

When processing at high temperatures a mildly alkaline, buffered borax developer is recommended. Alkali-free developers of the amidol type or one of the mildly alkaline fine grain developers such as Kodak D-23 are preferable to those with normal alkali content. Additionally, a pre-hardening bath such as Kodak SB-4 Tropical Hardener Bath or a specially formulated tropical developer may be used. 

Uses As a mild alkali accelerator in fine-grain developers and those of low activity in certain hardening fixing baths and in some acid hardeners, especially those intended for prints that are to be dried through heated belt driers and in gold toning baths to render them alkaline and to increase the rate of deposition of gold. 

Until the advent of 35 mm film, with the resulting emphasis on fine-grain developers, glycin was used mainly in paper developers. Now it is sometimes used in combination with other developing agents for fine-grain film development. 

The use of caustic alkali (e.g., sodium hydroxide) is not recommended with metol as there is a tendency to excessive fog. When used with sulfite alone, without additional alkali (Kodak D-23), metol provides a slow-working, fine-grain developer. This type of film developer often works well with a mild alkali, such as borax, which accelerates the rate of development without increasing the grain size appreciably (Kodak D-25). 

This is a fine-grain developer with medium to low contrast. The grain is softer than that produced by Kodak D-23. This formula was originally designed to produce fine grain for small format negatives. As with most fine-grain developers it will cause a loss of emulsion speed of at least one stop. 

This fine grain developer has unusually high speed and extremely fine grain due to the combination of p-phenylenediamine and pyrocatechin. 

Fine-Grained Development of FTM Using Micro-Aspects... 

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