Printing and Enlarging

Part of Photography

Printing converts the photographic negative into a positive print, and enlarging allows prints larger than the negative — the two output methods that distribute photographic information to the community.

Why This Matters

The negative is a means, not an end. The purpose of photography is distribution of visual information, and that requires prints. A glass plate negative stored in a box helps no one. Fifty prints from that negative — mounted on classroom walls, carried by field surveyors, kept in medical records — teach, document, and inform.

Understanding printing and enlarging as a unified system means understanding how negative quality, paper quality, exposure, and processing all interact to produce the best final result. A perfect negative can be ruined by poor printing. An imperfect negative can often be partly rescued by careful printing technique. Knowing both the contact printing and projection enlarging methods means you can serve any need: intimate small prints from 9 × 12 cm negatives, or large display prints from the same negatives with a simple projection device.

The content in this overview integrates the full printing process. For detailed treatment of each component, see the dedicated contact printing and enlarging articles.

The Negative-Positive Relationship

A negative is the reversed record of the original scene: bright areas appear dark (dense metallic silver), dark areas appear light (clear or thin). A positive print restores the original tonal relationships by passing light through the negative onto a second light-sensitive surface.

The reversal works because light through the dense negative areas (originally bright) exposes the print paper minimally — the print paper remains light in those areas. Light through the thin negative areas (originally dark) exposes the print paper heavily — the print paper becomes dark.

Tonal accuracy: The relationship between negative density and print density is controlled by:

1. Negative density range (how much contrast the negative contains)
2. Print paper contrast (how strongly the paper responds to density differences)
3. Exposure (which part of the tonal range is used)

A low-contrast negative (thin throughout) can be printed on high-contrast paper for a better result. A high-contrast negative (very dense highlights, very thin shadows) must be printed on soft paper or with reduced exposure in the highlights.

The Complete Printing Process

Step 1: Evaluate the negative

Hold the processed, dried negative against a light source (a window or candle). Examine:

• Overall density: Is it uniformly dark (overexposed), uniformly thin (underexposed), or has a good range?
• Highlight density: Are the brightest areas of the scene (densest in the negative) completely opaque, or do they retain some texture?
• Shadow detail: Do the darkest parts of the scene (thinnest in the negative) show any visible detail, or are they completely clear?

This evaluation tells you how to adjust the printing exposure and paper choice.

Step 2: Prepare sensitized paper

Choose paper appropriate to the negative:

• For a contrast-y negative: use a slow, soft printing paper (silver chloride)
• For a flat negative: use a faster, more contrasty develop-out paper
• For simple copies without fine gradation: cyanotype is adequate and requires no silver

In the darkroom, remove a sheet of paper from storage. Handle by edges only. Note: printing paper must be fresh; old, slightly-fogged paper produces muddy shadows.

Step 3: Contact printing setup

1. Place the sensitized paper emulsion-side up on a clean, flat board
2. Place the negative face-down on the paper (emulsion against emulsion)
3. Place a clean glass sheet over both
4. Apply pressure to hold contact: a heavy book, a hinged frame with springs, or weight on the glass
5. Any gap between negative and paper produces fuzzy print edges

Step 4: Exposure — contact printing

For printing-out papers: carry the loaded frame into sunlight and expose 2-20 minutes, monitoring progress.

For develop-out papers: expose to a lamp or brief sunlight (1-20 seconds), then develop.

Test strip method: Before committing a full sheet, expose a strip across the image at multiple time increments (5 strips × 10 seconds each = test strip showing 10, 20, 30, 40, 50 seconds). Develop the strip and choose the correct time.

Step 5: Processing the print

For develop-out paper:

1. Developer: 2-5 minutes until desired density
2. Stop bath: 30 seconds
3. Fixer: 5-10 minutes
4. Wash: 20-30 minutes

For printing-out paper:

1. Fixer only: 5-10 minutes
2. Wash: 20-30 minutes
3. Optional: gold tone before fixing for permanence

Step 6: Drying

Dry prints face up on clean cloth. Gelatin-coated paper curl as they dry; flatten by placing between clean boards under a weight while still slightly damp. Store flat when fully dry.

Projection Enlarging

For prints larger than the negative size, the negative is projected through a lens onto the paper below.

Enlarger setup:

1. Mount the negative in the negative carrier above the lens board
2. Set the height of the enlarger arm to produce the desired print size
3. Focus by projecting onto plain white paper and adjusting lens-to-negative distance
4. Stop down lens 1-2 stops for better edge sharpness
5. Replace white paper with sensitized paper in total darkness

Calculating enlargement: If the negative is N cm in one dimension and the desired print is P cm, the linear magnification M = P/N. The lens-to-paper distance = F × (M+1), where F is the lens focal length.

Example: Print a 9 cm negative to 27 cm print (M=3). With a 100 mm lens: lens-to-paper distance = 100 × 4 = 400 mm.

Exposure for enlarging: Larger enlargements require proportionally more light per unit area. Use the test strip method. A 4× enlargement typically requires about 8-16× more time than a contact print of the same negative, depending on the light source.

Dodging and burning: During enlarging exposure, you can:

• Dodge (lighten specific areas): hold a small card on a stick below the lens for part of the exposure to shade areas that would otherwise print too dark
• Burn (darken specific areas): cover the whole paper except the problem area and give extra exposure

Common Printing Problems

Problem	Likely Cause	Solution
Overall too dark	Overexposure or over-development	Shorter time or shorter development
Overall too light	Underexposure or under-development	Longer time or longer development
No shadow detail	Negative too thin; paper too slow	Use faster paper; reprint negative at longer exposure
No highlight detail	Negative too dense; paper too hard	Use softer paper; reduce printing exposure
Fuzzy edges in contact print	Poor contact between negative and paper	Increase pressure; check glass flatness
Fuzzy image from enlarger	Poor focus or vibration	Refocus carefully; stabilize enlarger
Uneven density across print	Uneven illumination	Reposition light source; add diffuser
Yellow stain after fixing	Exhausted fixer; insufficient washing	Use fresh fixer; extend washing
Mottled tone	Contaminated developer; cold developer	Check chemistry freshness; warm to 20°C

Print Quality Standards for Documentation

Different applications require different quality levels:

Legal documents and identity: Clean, clear prints with the full name and date written on the back. Face and identifying features must be sharp. Any ambiguity makes the record unreliable.

Medical records: Maximum detail. Use the finest-grain paper and the sharpest negative. If fine detail matters (wound depth, fracture pattern), use contact print rather than enlargement.

Teaching materials: High contrast and good overall tonal range. Wall-display prints should be large enough to see from 2 meters — at minimum A4 size (21 × 29.7 cm). Use enlarging to produce display-scale prints.

Survey records: Accurate tonal reproduction with good sharpness at the distance of key features. Include a scale reference in the photograph or in an added label.

Archival storage: Every negative should have at least one reference print made and stored separately. If the negative is damaged, the reference print documents what it showed. Store negatives and prints in separate locations.