Ilford published a leaflet on Fine grain processing suggesting this in the 60's around the time they introduced Perceptol.
TECHNICAL INFORMATION SHEET P10
FINE GRAIN DEVELOPMENT
The graininess of images obtained with conventional developers, i.e. Metol- or Phenidone hydroquinone carbonate developers, is sufficiently fine for contact prints and moderate enlargements, but when very big enlargements are made from small negatives graininess becomes increasingly apparent.
Special developers have been formulated to produce images of reduced graininess. Many of these developers restrict grain size by dissolving some of the silver forming the image. Since this causes areduction in density a longer exposure is needed to achieve a satisfactory density for printing. Thisloss of speed is characteristic of most fine grain developers but one developer which is exceptionalin achieving a high speed/grain ratio, (i.e. it combines high speed with fine grain), is Ilford Microphen Fine Grain Developer. A speed increase of at least 50 per cent is possible with most materials and it has the advantages common to Phenidone based developers in that it has a long working life and it is unlikely to cause staining on fingers or clothes.
Most other fine grain developers may be described in one of four categories as follows:
Metol- or Phenidone-hydroquinone borax developers, para-phenylene diamine developers, developers containing silver halide solvents, physical developers.,
Metol- or Phenidone-hydroquinone borax developers.
These are characterised by low alkalinity and a high concentration of sodium sulphite. Ilford ID-11and ID-68 are of this type and are based on Metol and Phenidone respectively.
The formula of ID-11 is:
Metol 2 g.
Sodium sulphite, anhyd. 100g.
Hydroquinone 5 g.
Borax 2 g.
Water to make 1,000 cc.
The formula of ID-68 is:
Sodium sulphite, anhyd. 85 g.
Hydroquinone 5 g.
Borax 7 g.
Boric acid 2 g.
Potassium bromide 1 g.
Phenidone 0.13 g.
Water to make 1,000 cc.
These formulae are for working strength solutions which are used without further dilution. One advantage of this type of formula is that no increase in exposure is necessary; another is that development times are not inconveniently long. The scope of such developers is not limited to small negatives, they are equally suitable as general negative developers.
Para-phenylene diamine developers
Developers in this group contain para-phenylene diamine and sodium sulphite with varying concentrations of glycin. They produce brownish images which show a very considerable reduction in grain compared with conventional developers but they require an increase in exposure of from 1¼ to 4 times, according to the type of developer and negative material. This loss of film speed may limit their usefulness. The developers in this group which achieve the greatest reduction in grain size are those which require the greatest increase in exposure.
The maximum contrast obtainable with these developers is rather low and development times tend to be long. They also have the disadvantage that they are toxic and stain fingers and equipment.
Developers containing silver halide solvents
Certain fine grain formulae contain silver halide solvents such as hypo and thiocyanate. These depend for their action on the fact that some of the silver dissolved during development is redeposited in a very fine form to reinforce the final image. Ilford ID-48 Developer is of this class.
Such developers give considerable reduction in grain size but require 50 to 100 per cent extra exposure. Both Ilford ID-11 and ID-2 developers may be simply modified to work in this way.
ID-11: Add ammonium chloride to ID-11 in the proportion of 20 g. per 500 cc working solution.
Camera exposures should be increased by about 50 per cent and the development times are double those specified for ID-11.
ID-2: To ID-2 diluted 1 + 2 add ammonium chloride in the proportion of 5 g. per 500 cc. developer.
Physical developers
These developers contain silver in solution and the developed image consists of very finely divided silver deposited by the action of the developer on the latent image instead of being derived from the silver halides in the emulsion. They give extremely fine grained images which are to some extent independent of the nature of the negative emulsion used. Such developers have, however, found only limited application. Their activity and the fog level they produce fluctuates greatly according to the concentrations of the constituent chemicals, consequently great care is needed in making up the formulae. A high standard of cleanliness is required to avoid ontamination of the developer and regular checks on activity are necessary.
Ilford, Phenidone and Microphen are trade marks
ILFORD LIMITED.
ILFORD. ESSEX
TIS/P1O-5/B65. Printed in England
Hope that helps
Ian
