What is the Black and white printing techniques?
Making contact prints post photographers make contact prints – small prints made direct from the film held flat against the paper – from all their negatives as soon as they are processed. This is a good idea as it allows you to preview all your exposures as positive prints, making it easier to pick and choose which shots to enlarge, mark up possible cropping, etc. It also aids filing as it makes images much easier to locate in the future.
To make contact prints plus a contact-printing frame or at least a 10×8inch sheet of clear plate glass. Some negative bags are completely transparent, and it is possible to simply lay one on top of the paper with a sheet of clear glass on top to hold the negatives flat. Set up the enlarger so it projects an even patch of light on the baseboard slightly larger than your paper. Reduce the lens aperture two or three stops from its widest (brightest) setting. If your enlarger has a red filter below the lens, you can swing this in place to allow the paper to be positioned without fogging it; alternatively mark up the baseboard with tape, etc. to show where the light will fall.
Switch off white room lights. Place a sheet of grades 1 or 2 paper, or variable-contrast equivalent, emulsion upwards on the baseboard. Lay out your negative’s emulsion-downwards (glossy side up), on the paper, and cover them with the glass. The glass presses the negatives down flat, so they are in complete contact with the paper. If you use a special contact frame, you can first slip negatives into thin transparent guides on the underside of the glass. This makes things easier when printing more than one contact sheet of a film.
Exposure varies according to the intensity of your light patch, and negative densities. As a guide, having switched off the enlarger and swung back the filter, use your timer to bracket trial exposures in a test strip. Set the timer to 5 seconds and expose the whole sheet for that time. Now cover up part of the paper with a piece of opaque card and expose the remainder for another 5 seconds. Cover a little more of the paper and reset the timer to 10 seconds before giving the rest an exposure for this time. Remove and process the paper (Develop–Stop–Fix) waiting until fixing is complete before you view the results in white light.
Rinse the contact sheet and hold it out of the solution; prints look deceptively pale under water. They also darken slightly when dried. The print will have clear bands of exposure, each darker than the last across it, representing 5-, 10- and 20-seconds’ exposure. The darkest band of density on your print received the longest exposure time.
This method follows the logic of the camera’s exposure controls in that each step is double the exposure of the previous one, equivalent to increasing exposure by one f-stop on your lens each time; this is known as the f-stop method. You can use various multiples, for example, 2, 4, 8, 16, 32, etc.
The trick to remember is that you expose all the paper at the start, and then cover up a small part of the paper and repeat the first exposure time; from then on in you start doubling the times. If the first exposure was 5 seconds, by covering up part of the paper the bit now hidden from the light has received only 5 seconds of light; by exposing the rest of the paper again by 5 seconds the paper has received 5 + 5 = 10 seconds of exposure. You continue this by covering up more of the paper so that the bits hidden have received 5 and 10 seconds of light respectively, and now give the paper 10 seconds of exposure so that the last piece would have received 5 + 5 + 10 = 20 seconds.
This can go on until you run out of paper to cover up; the next exposure would be 20seconds, so that it is 5+5+10+20=40; the next exposure would be 40 seconds and after that 80 second and so on. If none of the steps looks right, with everything either too dark or too light, a farther bracketed test may be required. Open or close the aperture or make the exposure times longer or shorter. Once you have a reasonable looking test strip, you can decide from the most promising band of density what exposure will be correct. Set this exposure on the timer and make a single exposure of the whole sheet.
Of course, if the set of negatives you are printing varies greatly in density, the correct contact-sheet exposure will have to be a compromise between darkest and lightest frames. Variations will be less if you use soft rather than hard contrast paper. It is important that contacts show the detailed picture content of every frame, even if their print quality must look rather flat at this stage.