تجهيز المخبر .. اختيار واستخدام المواد .. كتاب التصوير الضوئي

Preparing the laboratory .. Choosing and using materials .. The book of photography

Choosing and using materials
Preparing the laboratory

- Setting up the laboratory:

A permanent laboratory allows you to work at any time without prior preparation. Unfortunately, few amateurs can afford this luxury. They can only use one room in the house and must quickly return this room to its previous state. These are the circumstances that require choosing any room: a friend's room, a shed or a room under the stairs. With all this, we can work very effectively in a narrow space if it is properly equipped.

It is not necessary to have running water in the room used as a laboratory, as films and photos can be washed elsewhere after passing through the stabilizer. In this case, transfer them to a deep container (a bucket, for example) and not to a regular container so as not to spread water on the floor.

Ventilation or heating in winter improves working conditions. Wall fans must be light-proof.

- Laboratory blackout:

The black room must be completely dark. It is not enough to appear dark when the electric light is turned off: it must be completely dark when the eyes get used to the darkness, that is, after about ten minutes of silence.

A temporary laboratory can be made dark by curtains or pieces of plywood or opaque plastic that close the windows. Place a piece of cloth under the doors and do not forget the lock hole and the rest of the openings through which outside light can enter. Sometimes double opaque curtains are enough and can also be left permanently if they are hidden in normal times by decorative curtains. Be generous with the length of the curtains and try to black out the laboratory when the outside light is at its peak.

- Furnishing the interior of the laboratory:

A black room does not mean that the walls must be painted black! On the contrary, the ideal ceiling and walls are painted white: this gives an excellent distribution of light used for black and white drawing operations. Except for the wall behind the magnifier: most magnifiers emit distorted light at the level of the negative carrier and should not distort the paper after reflection on a white surface. In a temporary laboratory, it is sufficient to fix a piece of black paper behind the magnifier to avoid this danger.

A sturdy table is required that can bear the weight of the magnifier. The height of this table is very important: the magnifier should not touch the ceiling at the maximum magnification and a low position magnifier is uncomfortable. A height of about 85 cm seems correct.

The (wet) areas should be separated from the (dry) areas: It is obvious that solutions and chemicals should not be in contact with the magnifier, the films to be enlarged and the sensitive paper. If there is no room in the laboratory, place your tanks on a table protected by a tarpaulin cover so that the chemical solutions do not affect them.

No matter how clever and attentive you are, it is impossible not to spread small amounts (and even large amounts in the event of an accident) of chemicals on the floor. Take precautions as a result. If you cannot remove the carpet, cover it with a piece of tarpaulin or old newspapers. In the bathroom, you can place a piece of wood on the bathtub and then place the treatment basins on it: a little water at the bottom of the bathtub prevents stains from forming on its surface. It is better to announce on the entrance door of the laboratory that this room is occupied to prevent any entry into it, and it is also preferable to put an internal latch. Protect the electrical switches with a piece of plastic or use switches with a rope. This last method, which is recommended in any wet room, prevents dirt and electrification at the same time.

- Laboratory layout:

If it is a permanent laboratory, everything must be made to allow excellent working conditions: the floor must withstand water and chemicals and be easily washed. Modern plastic cladding is perfect.
The edges of tables, shelves and other furniture should be marked with a line of white paint, which will enable them to be seen in the dark. Sometimes sticky phosphorescent pieces are used, which can be seen in complete darkness without distorting the films if the latter are not set aside.

A sufficient number of electrical outlets must be provided because the machines that use electricity are abundant in the modern laboratory and the electrical wires on the floor are annoying and dangerous at the same time. A laboratory timer is fixed on the wall (it has numbers and a phosphorous needle). You can also permanently hang the methods of use and other practical information.

Some operations are carried out outside the laboratory such as retouching, pasting enlargements, drying negatives and placing them in their envelopes, etc. Many photographers perform the polishing and drying process in another room. In fact, if the laboratory is large and well-ventilated, it is preferable to polish and dry in this room because

Colored photos emit waves that can be annoying in another room of the house.

- Choosing and using the sink:

It is preferable to use a large-shaped sink or basin. This sink can be made of ceramic, plastic or stainless steel, provided that these materials are not affected by chemicals, especially bleaching materials in processing color photos.
Most photographers work from left to right, that is, the reagent basin is on the left and the wash basin is on the far right. Before placing the photographs for drying or polishing, they can be filtered and dripped onto a slanted glass or plastic plate. Paper or a towel to dry the hands is essential. Basins and chemicals can be arranged under the sink.

- Preparing the equipment:

Normal light should not directly illuminate the base of the magnifier, as this not only distorts the sensitive paper but can distort the instructions given by the positometer for magnification or by the color analyzer. In any case, a laboratory lamp can be connected in such a way that it turns off when the magnifier is turned on.

We can use several sources of lighting: a ceiling lamp provides general lighting while one or more lamps illuminate specific areas: especially the black and white reagent basin. Orange light is suitable for most sensitive black and white papers. As for the standing green light that we sometimes use in color, it is so light that complete darkness is preferred. The lamp, which has no chemical effect, should be weak (recommended by the paper manufacturer) and should not be placed near sensitive surfaces.

The base of the magnifier is often provided with a margin regulator. The chronometer, the bosometer and the analyzer (if present) should be placed near the base.

The necessary items for the make-up can be hung on the wall within easy reach or arranged in a drawer on the table. A pair of scissors for cutting paper and finished pictures is very useful. Sensitive paper is arranged in sealed boxes near the magnifier.

- The laboratory and its equipment:

1 - Power circuit breaker

2 - Wall fan

3 - Wash basin

4 - Paper towels

5 - Small basins

6 - Wooden boards on which the basins are placed

7 - Bucket

8 - Trash can

9 - Safety lighting

10 - General lighting

11 - Wall cabinet

12 - Magnifier

13 - Flat polisher

14 - Lamp that emits radiation that has no chemical effect

15 - Chair

16 - Scissors

17 - Margin organizer

18 - Time counter

19 - Classification cabinet

20 - A piece of furniture with drawers.