| 摘要 |
<p>There is described a concentrated developing solution which comprises per litre of water 100 to 300g of sodium sulphite and from 50 to 150g of potassium sulphite the % by weight ratio of the sodium sulphite to the potassium sulphite being from 25:75 to 75:25, a total of from 30 to 50g of at least one silver halide developing agent, a buffering substance, sufficient sodium hydroxide to yield a pH of from 8.0 to 11.5 when the concentrated developer solution is diluted 1 plus 4 water, and as the sequestering agent from 5 to 40g of diethylene - triamine - pentaacetic acid. It has been found that the choice of DTPA as the sequestering agent lower the resolution temperature of the developing solution. Thus the concentrated developing solution can be stored at a lower temperature than if other sequestering agents had been used.</p> |
