تحميض الورق الحساس الملون .. كتاب فن التحميض والطبع والتكبير

Fourth: Developing colored sensitive paper

The development of colored sensitive paper is not much different from the development of black and white sensitive paper. But here it is necessary to pay full attention to the temperature and acidification time. With the exception of Kodak paper, Ektaflex PC, which is developed in a special device with a single solution, the colored sensitive papers. It undergoes acidification processes similar to black and white.

In view of the rapid progress in color technology, I will mention an example of the development of colored sensitive paper, but the reader must follow the instructions mentioned with the development chemicals, which are subject to change from one moment to another.

As for the acidification of colored sensitive papers in the color processing drum, the method of preparing chemicals for use in the cylinder must be adhered to, which is usually more concentrated (about 20% more) than acidifying solutions that are used in ponds. The reason for this is that the first step, which is the stage of getting the paper wet, causes a dilution of the highlighting solution.

The following is an explanation of the method of developing Kodak 78 Ektacolor 74PC or Ektacolor papers in the development cylinder. As for the acidification in the ponds, it is carried out with the same steps, while following the same instructions previously mentioned in the acidification of white and black papers. The acidification is carried out in the following steps:

A- Preparing and preparing acidifying solutions and devices:

1- Color sensitive paper can be developed in vats such as black and white, and most professionals do this. For amateurs, it is best to use a cylinder. Processing drum due to its ease of use and ease of adjusting the temperature in

One water bath, it also consumes less chemicals, occupies a smaller place, and leaves can be acidified inside it in normal light. Colored acidification chemicals are sold compounded and ready for use, or they are sold in the form of powders or concentrated solutions that are dissolved in water. The solutions are prepared in the manner mentioned in the instructions, according to the order (see chapter of chemicals).

The chemicals bottles as well as the calibration cups are placed in a water bath whose temperature is slightly higher than the required degree, so that you hardly finish exposing the sensitive paper under the head of the magnifier, for example, except that we find that the temperature of the solutions has become the required temperature. A good thermometer should be used to measure the temperature of the water bath.

One of the best and cheapest acidification devices is the Paterson device, which contains an acidification cylinder, colored plastic bottles, and colored calibration cups. All this in a deep basin that acts as a water bath. A device can be installed to adjust the temperature automatically, and a motor can also be installed to rotate the acidification cylinder.

There are more expensive devices such as devices produced by companies such as

. Durst, job

The important thing is to put the plastic bottles of the solutions in the water basin for a sufficient period before the start of the acidification so that they gain the required temperature, due to the poor conduction of heat by plastic. With regard to the acidification cylinder, this must be completely dry from the inside so that sensitive paper does not stick to it and deteriorate. And take the developing cylinder with you next to the enlargement device so that you put the sensitive paper or sensitive paper inside the cylinder immediately after the end of exposing the sensitive paper.

Set the stopwatch next to the acidifiers. A separate basin was prepared for washing if desired, and the leaves can be washed inside the acidification cylinder.

2- Exposing the sensitive paper and placing the paper in the developing cylinder: in complete darkness and it is not preferable to use safety light due to the sensitivity of the colored sensitive paper. The sensor is towards the cavity of the cylinder, and the paper backing is adjacent to its walls.A mistake in placing the sensitive paper makes the sensitive surface touch the walls, which leads to chemicals not reaching the image well and not showing it.Close the developing cylinder well.

Now you can turn on the light!

The rest of the steps are done in normal light. Place the acidification cylinder inside the water bath and rotate it for a minute until it acquires the appropriate temperature. In this explanation, we will mention the exposure times at a temperature of 33 °C and the quantities of solutions for a cylinder with a paper capacity of 8 x 10 inches. For the use of other temperatures or cylinders of different capacities, see the table and drawing in Appendix 7, 10).

B - Acidification:

1- Wetting the sensitive paper stage: Pour 500 cm3 of water into the cylinder at a temperature of 33 °C. Aquarium water can be used if you are sure that it is not contaminated with chemicals. Turn (Roll the roller continuously at a slow but regular speed for 30 seconds. The purpose of this stage is to raise the temperature of the roller and sensitive paper to the required degree, as well as to soften gelatin layer, 10 seconds before the time expires, pour water from the cylinder into the

the sink.

2- The highlighting stage: Pour 70 cm3 of the developer solution into the developing cylinder (using measuring cups or containers). Start the stopwatch, turn the cylinder at a slow, regular speed for 3 minutes. Ten seconds before the time expires, pour the developer solution into the drain, and at this stage a silver image appears. And colorful.

3 - The stopping stage: pour 70 cc of the stopping solution into the cylinder, rotate the cylinder for 30 seconds. Pour the stopping solution and at this point stop making the appearance.

- The bleaching and fixing stage: pour 70 cm of the bleaching and fixing solution (one solution) and continue in the same way mentioned above for a minute. The purpose of this stage is to remove the silver image and install the color image.

E - The washing stage, and this can be done in the acidification cylinder by pouring 500 cm 3 of water into the cylinder and spinning it for a period of not a minute, then pouring the water and repeating the process four times. It is better to open the development cylinder after the installation stage and take out the sensitive paper. Gently, then put it in a wash basin with running water for an hour. The purpose of this stage is to remove chemicals from sensitive paper.
- The acidification of agfa leaves is no different from this method, and solutions are usually sold

Ready to use

- In the case of acidification in basins, a number of leaves can be acidified in

Basin note the large volume of the solution ».