طريقة التكبير ، أو خطوات العمل .. كتاب فن التصوير الفوتوغرافي

Zoom method, or action steps

Place the negative crystal in the amplifier

Wipe the dust off the negative crystal with a very soft brush of camel hair, by wiping its surface gently and softly, and do not wipe hard, because that generates a charge of static electricity that attracts more dust to the crystal. When the air is very dry, the film becomes easily electrified, so use a medical syringe to expel the dust by directing the tip of the syringe to the negative side and injecting the air with short, sharp strokes.

When the negative becomes clean, place it in the holder prepared for it, so that the surface coated with the sensitive material (the dark surface) is facing down, and insert it into the magnifier as shown in picture 5.

- Prepare the photographic paper holder

Adjust the movable characters in the photocopy paper holder to the paper you want to use. Do not place sensitive paper in the holder at this point. Instead, place a plain white sheet of paper on which to practice focusing and place the holder under the magnifier.

If the surface of the holder is painted white to enable you to dispense with the white paper for the focus experiment process, put a black paper on it because photographic paper, no matter how thick it is, is light-permeable. The result is that the high-light areas of the image tend to turn gray instead of remaining white.

Drop the negative crystal image onto the sensitive paper

Turn on the magnifier, and raise or lower it until the rectangular image is the desired size. Focus roughly. Leave the fine focus until the last minute. Move the sensitive paper holder until you get the frame you selected on the example copy.

The reason for leaving the accurate focus process until the last moment is that the negative crystal, under the influence of the heat of the magnifier light, expands and curves, so if this happens before the exposure process, the image comes cloudy and unfocused, and for this reason you must do the exact focus immediately before the projection exposure process . But if the carrier of the negative crystal is of the type consisting of two crystals with the negative in between, which prevents curvature, then there is no need to take this precaution.

If the negative is high in intensity, or the magnifier is ineffective, focusing becomes difficult. There are some devices that assist the focus process, and are inexpensive, and you can buy them, and we will talk about this topic later, picture (6).

Determine the aperture of the magnifier lens

The next step, after the final focusing process, is to narrow the aperture of the enlarger lens.
This restriction is necessary for three reasons:
1- To improve the accuracy of the lens.
2- To increase the depth of field.
3- Determine the most appropriate exposure level.
Let's study these reasons in detail.

1- Improving or correcting the accuracy of the lens

No lens can give its most accurate image if it is open to the maximum. Good lenses need to narrow their aperture by one f-number less than their maximum aperture.
A bad lens needs to narrow its aperture more than that to give a completely clear picture.

2 - Increase the depth of field

Most types of holders for the negative crystal in the amplifier are of the type that holds it by its edges. Under the influence of the heat of the magnifying lamp, the crystal curves out of the fine focus field. We mention how narrowing the lens aperture of the magnifier increases the depth of field, which makes any slight movement of the crystal not affecting the clarity of the image. Of course if the mount is the type that holds the crystal between two glasses you don't have to worry about the depth of field as long as the focus is accurate, but it is safer nevertheless to narrow the aperture of the magnifier lens, because it is difficult to be sure of the accuracy of the focus if the image is low in light, or if it is Its lines are imprecise.

3- Determine the most appropriate exposure level

Your personal judgment is the most important factor in this determination. If you want to get the best possible enlargement of a crystal, and you want to block the light from some of its parts to make it lighter, and expose another part for a longer period to make it deeper, the aperture is small to enable you to expose for a period of time of not less than ten or fifteen seconds, which gives you enough time. To control a process on the other hand, let's say you have a negative print roll of 35 mm and you want to make a projection experiment of small images for all the roll, to choose the best one to enlarge it in a good way.
In this case, leave the lens wide open to make the exposure time as short as possible.

If we consider the above three factors, an aperture equivalent to f/11 is a decent aperture for a normal zoom, i.e. you can start with this aperture.
Then check the focus one last time, and make sure the projected image is framed in the paper holder as you want it to. Push the red filter on the enlarger under the lens. The presence of the red filter under the lens makes it project a faint red image that does not cause exposure on sensitive paper. Peel the plain white paper from the paper holder. And turn off the amplifier.
Everything is now ready to be enlarged and printed. Despite this, the first experience in printing will be an experiment in slides to help us choose the appropriate time period for exposure, as well as the correct f-stop aperture.