Low-contrast developers

Start by adding 25.0 ml of stock solution of a high or normal contrast developer, such as D-72, to each liter of working solution low contrast developer, such as Ansco 120 1 1. 

The disadvantage of combining developers is that the high or normal contrast developer, which usually contains hydroquinone, may exhaust before the low contrast developer. This is not a problem if only a few prints are to be made from one negative, which is often the case when using developers in this way. However, if consistency is important for a large number of prints, it is important to make certain there is sufficient high/ normal contrast developer in solution. 

Figure 2 shows the exposure characteristics for azide-styrene resin resist film with an azide concentration from 10 to 40 wt% (based on the styrene resin weight) and Figure 3 shows the contrast of the resist films as a function of the azide concentration. Development was done with a 60s immersion in 0.83% TMAH solution. The styrene resin matrix alone has been found to be a negative deep UV resist. However, rather low contrast (1.48) and low sensitivity (2.5 J/cm2) are observed. The contrast and the sensitivity of the styrene resin is remarkedly increased by adding the azide, as shown in Figures 2 and 3. 

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. 

PCTEA is a Phenidone-ascorbic acid developer with triethanolamine (TEA for short) activator. Using this formula, I can t find the grain in HP5+ orTMAX 400 at less than a 20-power enlargement. Even in very thin negatives of low contrast, shadow detail is still apparent. The following formula may be scaled up to any desired amount. 

Another difference is that it is not easy to formulate a higher-than-normal contrast developer using Phenidone. At the same time, it is relatively easy to adjust the contrast, high or low, of a MQ developer, making the MQ combination easier to work with when using or formulating a print developer. 

Glycin is very sensitive to bromide and also to low temperature. With alkali carbonates it makes slow-working developers, which have good keeping properties and give low contrast. Must not be confused with glycocoll medicinal, sometimes called glycine. 

At temperatures below 50F/10C hydroquinone developers are inactive. It is extremely susceptible to the action of bromide. When compounded with alkali carbonates it gives a slow-working but high contrast developer. With caustic alkali (e.g., sodium hydroxide) its action is very rapid, with the highest possible contrast. For this reason, it is the most widely used developer for technical applications, especially in process work where the highest attainable contrast is essential. In the presence of caustic alkali (i.e., high pH) it is not temperature-sensitive and can be used for low-temperature developing. Hydroquinone developers keep well and are slowly exhausted. 

Used alone in sodium carbonate/sulfite solutions, it is very fast but extremely soft working and is only capable of producing negatives of low contrast. In combination with hydroquinone it produces developers with superadditivity that are even more efficient than MQ developers. 

Borax produces the finest grain with the least contrast, metaborate produces medium grain with low contrast, and sodium carbonate has the highest contrast, coarsest grain, and greatest film speed. For minus development, use borax in the second bath. 

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 developer is good for low contrast and maximum shadow detail. The commercial product, marketed by Kodak, is the world s best-selling black-and-white developer. 

Normal dilution is 1 1 with water. For high contrast, use full strength for low contrast, use 1 2 with water. The useful development range with bromide papers is 2 to 6 minutes. With chlo-robromide papers it is 1 G to 3 minutes. 

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