HC-110
From Silvergrain Labs
HC-110 is a highly concentrated developer manufactured by Eastman Kodak Company.
The image quality of this developer for pictorial applications is poor and I see no advantage in this product other than convenience, low cost and rapid processing. The disadvantages are: speed comparable to D-76 or often slightly lower, coarser grain than D-76 (except for some films including TMX) and mediocre sharpness. The image quality may be acceptable for large format users, but it's not the first choice for medium format and 35mm work.
However, this developer is probably one of the most cleverly formulated products. Details of this product can be seen in Henn, King and Surash (1971), US Patent 3552969.
| US Patent 3552969 Example 1 | |
|---|---|
| diethanolamine | 31.0 g |
| diethanolamine | 9.0 g |
| diethanolamine hydrobromide | 1.5 g |
| Phenidone | 0.5g |
| hydroquinone | 6.0 g |
| ethanolamine | 5.0 g |
| ethylene glycol | 10.0 g |
This concentrate was diluted 1+31, and 0.25g of poly(vinyl pyrrolidone) was dissolved in each liter of diluted working strength developer. The specified PVP is Grade K-15 of MW about 10kD.
PVP is effective when silver complexing agent is organic amine compounds. In HC-110 type developer concentrate (to be diluted 1+31), 0.25 to 0.5 g/L of PVP of MW 10kD to 40kD is effective. Larger polymers are said to be as effective but they are more difficult to dissolve in water.
PVP was used as an antistaining agent in quantities 3 to 15 g/l in monobath developers containing a large amount of thiosulfate, which is a very strong silver halide solvent. See Levy (1965) US Patent 3167429.
PVP is used for a wide range of non-photographic applications, such as:
- clarification of beer and white wines (removal of excessive polyphenols)
See poly(vinyl pyrrolidone) for more info.
Ilfotec HC
Ilfotec HC is a very similar product.
The Ilford MSDS indicates that Ilfotec HC contains the following (and perhaps a couple more agents in less than 1% concentration):
| Ilfotec HC MSDS | Developer | Replenisher |
|---|---|---|
| diethanolamine sulfur dioxide complex | 60-100% | 30-60% |
| diethanolamine | 5-10% | 1-5% |
| diethylene glycol | 10-30% | 30-60% |
| hydroquinone | 5-10% | 5-10% |
| Na5 DTPA | < 3% | 1-5% |
| diethanolamine hydrobromide | 1-5% | 0-1% |
| phenidone B | 0-1% | 0-1% |
As we see, Ilfotec HC works around the Henn et al's patent by avoiding PVP. It is also noted that ethanolamine is dropped from the Ilford version, probably to reduce the degree of solvency to avoid problems in absence of PVP. (Monoethanolamine dissolves silver halide more strongly than diethanolamine.)
If Ilfotec HC contained other antistaining agents (see dichroic fog) in quantity smaller than 1%, they may not be listed in MSDS, so this possibility is not excluded.
