(7) ;Remove the film from the reel and hang it up to dry. Use film-hanging clips or clothes pins of the clamp type. Hang the film with one clip and attach another to the bottom. When the film has been hung up, wipe it clean with a wet chamois cloth, a sponge (of a special photographic type), or a wet piece of absorbent cotton (fig. 272). Wipe both surfaces free of excess moisture. Do this gently to avoid scratching the film. Handle the film by the edges only during this entire process. Let the film hang, in as dust-free a spot as possible, until it is completely dry, about 1 hour in normal humidity. Prints may then be made. The materials necessary for tank development are:

Thermometer

Figure 272.

Tank, bakelite or steel.

Thermometer.

Developer, D-76, or equal.

Short stop, acetic acid.

Hypo, acid hardening and fixing bath.

Film clips or clothes pins.

Chamois cloth, sponge, or absorbent cotton.

Graduate, 32-ouncc.

Safelight (for orthochromatic film).

Timer (not necessary).

Tank Development

Panchromatic film should never be developed in a tray because it requires absolute darkness. The tray solutions are difficult to manage in total darkness. Orthochromatic film may be handled in a red safelight (Wratten series 2) which makes the tray process easier. For tray development a faster developer is needed than for tank development. Kodak D-72, the same developer to be used for prints, is suggested.

Arrange three trays and mix all three solutions (developer, short stop, and hypo) before turning off the white light. The short stop and hypo are prepared exactly as they were for tank developing, and are poured into the second and third tray respectively.

Prepared developer is simpler, but developer may be mixed from the basic chemicals, as follows:

;

Avoirdupois

Metric

Water (about 125°F)

16 ounces

500.0 cc

Elon (metol)

... 45 grains

3.1 grams

Sodium sulphite desiccated

11/2 ounce

45.0 grams

Hydroquinone

21/4 ounces

12.0 grams

Sodium carbonate, desiccated ..

21/4 ounces

67.5 grams

Potassium bromide

27 grains

1.9 grams

Water to make

32 ounces

1.0 liter

For an 8- by 10-inch tray make about 15 ounces of diluted solution by adding 5 ounces of the above stock solution to 10 ounces of water. Stir this solution thoroughly and pour it into the first of three trays. Check the temperature.

Tray-developing times are much shorter than those in a tank. Average time for the above developer when diluted is about 4 minutes at 65° F., or 3 minutes at 70° F. It is best not to use the developer above 70° F. because it is difficult to control the developing in such a short time.

Before starting to develop the film, presoak it in plain water at the same temperature as the developer. Prepare the film for developing by unrolling it (in the dark or by the light of the proper safe-light) and tearing off the paper leader and backing. Be careful not to turn loose one end of the film suddenly since it will reroll very quickly and will be scratched. Put a film clip on either end of the film and bend the film into a U-shape, being careful not to coil it. Lower bottom of the U into a tray of plain water, and pass the film back and forth until the entire length is wet (fig. 273). Lift it out and drain it.

Pass The Film Back And Forth

Figure 273.

Lower the bottom of the U into the developer and notice the time. Move the ends up and down slowly; be sure that the entire length of the film is immersed during each up-and-down motion. Lift the film up, drain it, and lower it into the short stop. Lift the ends up and down again. Continue this motion for about 2 minutes. Lift the film, drain it, and lower it into the hypo. Start the up-and-down motion again and continue for 10 minutes. The white light may be turned on after about 3 minutes. After 10 minutes, drain the film thoroughly and wash it for about 30 minutes in running water or in 7 or 8 successive baths of 5 minutes each. The procedure for hanging, wiping, and drying the film is the same as that in tank developing.

The materials needed for tray development (fig. 274) are:

The Materials Needed For Tray Development

Figure 274.

Developer, D-72, or equal.

Short stop, acetic acid.

Hypo, acid hardening and fixing bath.

Two metal clips.

Chamois cloth, sponge, or absorbent cotton.

Graduate, 32-ounce.

Safelight, for orthochromatic film.

Timer (not necessary, but helpful).

Thermometer.

Stirring Rod.

Printing

Before discussing the actual procedure for making prints, it is necessary to explain several other points, such as the types of printing and the choice of paper.

Types Of Printing

There are two general types of printing: contact printing and projection printing. In contact printing the paper and the negative are in direct contact. A picture of the same size as the negative results. This picture is then called a contact print. In projection printing the negative is placed between a light source and a lens. The light rays are then projected down onto a piece of printing paper. By varying the distance from the negative to the paper, a print of any size can be made. The usual print made this way is larger than the negative and is called an enlargement. The equipment for projection printing is much more complex than that for contact printing. Contact prints will suffice for any practical purpose unless the negative is very small.