طريقة تحضير المحاليل ٢-a .. كتاب فن التحميض والطبع والتكبير

Solutions for showing sensitive paper

Although sensitive paper can be shown in film-revealing solutions, it is preferable to use more concentrated solutions for sensitive paper.

For ease, I will mention a solution suitable for developing films as well as sensitive paper, with changing the dilution of the solution with water.

Dilution: 1:1

Sensitive paper is placed in the first solution, then in the second solution. The variation varies according to the time that remains in each solution, so that the total period does not exceed two minutes at a temperature of 20 °C.

General notes on show solutions:

A- To obtain medium contrast and fine granules, the ratio of methol: hydroquinone should be between 10:2 and 1:4, and the alkalinity of the solution should be medium.

2 - To obtain a strong contrast and large granules, the ratio of methol to hydroquinone must be more than 1:6, or we dispense with methol and also increase the alkalinity of the solution.

3- To obtain low contrast and very fine granules, the ratio of methol to hydroquinone should be less than 1:2, or we can dispense with hydroquinone and reduce the alkalization of the solution.

4- To obtain warm black colors, we reduce metol and increase potassium bromide up to 0.3% of the volume of the solution.

5- To obtain cool bluish-black colors, we increase the amount of metol and reduce the concentration of potassium bromide to a lower one.

6- Sodium sulfite must be dissolved before hydroquinone in warm water to help dissolve hydroquinone.

7- The mentioned times for acidification in a small acidification tank (tank) with stirring for five seconds every 30 seconds at a temperature of 520°C.

8- The mentioned quantities for sodium sulfite and sodium carbonate are for the anhydrous powder, and in the case of using crystals, the quantities should be adjusted as previously mentioned.

9- Increasing alkalinity helps speed up the appearance.

10- Increasing the stirring reduces the acidification time.