Rollei RST produces a strong shade of brown in the black and grey tones. It is applied in a two-bath process (A bleach bath | B toning). The intensity of the toning process can be controlled via the temperature. The stop time for PE/RC/baryt papers and films is 1 minute.
Part A – Bath: In the first bath A the silver image is removed by the bleacher except for a small amount. Afterwards, this chemistry must be completely removed from the photo paper, preferably under running water. The duration of stay depends on the residual silver content. Approximately 2 to 4 minutes at 20 – 25°C have proven to be successful. Strong intermediate soaking of 3 – 5 minutes. Shorter & safer is to rinse directly under running water.
Part B – Bath: In the second bath, the toning bath, a brown dye is built up. The dwell time ends when the image has reached the desired strong brown image tone. Approximately 3 – 5 minutes have proved to be successful.
Hint: The shorter the dwell time in the Part A bath, the more image silver remains, so the brown tone in the Part B bath becomes stronger. Well-developed images (possibly a little too dark) are particularly well suited to achieve a rich brown tone.
DILUTION 1 + 9
900 ml water + 100 ml RST = 1 l solution| temp.: 20 – 25°C / 68 – 77°F
250 ml RST A & 250 ml RST B concentrates reach for about 0.15 – 0.35 m²