# The Enlarger and the Print

Photography I · The Black-and-White Analogue Laboratory · https://tryals.app/learn/photography-i/the-enlarger-and-the-print

## The Machine

An enlarger projects an illuminated negative down onto paper. The light source alters the image quality.

| Type | Light | Effect on the print |
|---|---|---|
| **Condenser** | Collimated lenses | Higher contrast, sharper grain, visible dust |
| **Diffusion** | Scattered glass | Lower contrast, softer grain, forgiving |

This difference stems from the **Callier effect**. Silver grains scatter directed light away from the lens, boosting contrast.

## Magnification and Geometry

Magnification is the print-to-negative ratio. A 50 mm lens at 5× magnification sits 300 mm from the baseboard.

Illuminance falls as the square of magnification plus one:

**new time = old time × ((m2 + 1) / (m1 + 1)) squared**

An 8-second exposure at 3× becomes 8 × 2.25 = **18 seconds** (or 18 s) at 5×.

## Working in Stops

Print exposures behave like camera exposures. Geometric steps—such as 4, 8, 16, 32 seconds—give equal one-stop increments. Arithmetic steps like 5, 10, 15, 20 seconds give shrinking tonal jumps.

* A one-third stop increase multiplies time by **1.26**.
* A half-stop increase multiplies time by 1.41.

Focus wide open with a grain magnifier. Stop down two stops before exposure. Always develop for the **full recommended time** to ensure rich blacks.

Account for **dry-down**: dry prints look darker than wet ones.

> **Common pitfall:** focusing stopped down. Always focus wide open for maximum brightness and critical sharpness, then stop down to expose.

## Practice questions

9 of this lesson's 14 practice questions, with answers. The full set is in the app.

### 1. A printer moves from a small print to one twice as large on each side and finds that the old exposure time now gives a print that is far too light. Why does enlarging the picture cost so much light?

A. Raising the enlarger head increases Callier scatter, losing light from the projector.
B. Stopping down the lens two stops maintains critical depth of field across wider paper.
C. Larger paper sheets feature thicker emulsion needing higher light energy to form images.
D. Light spreads over an area scaled by magnification squared plus one, dropping intensity.

**Answer:** D. Light spreads over an area scaled by magnification squared plus one, dropping intensity.

**Why:** Because illuminance is light per unit area, and the area grows as the square of the magnification plus one. Doubling each side of the print spreads the same lamp output over four times the paper, so roughly two stops of exposure vanish. The paper sensitivity and the lens aperture have not changed, only the density of light arriving at the baseboard.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/a-printer-moves-from-a-small-print-to-one-twice-as-large-on-each-side

### 2. A condenser enlarger produces a more contrasty print from the same negative than a diffusion enlarger does.

**Answer:** True

**Why:** **True**, by the **Callier effect**: collimated light scattered by the silver grains leaves the projection path, so dense areas read denser than their diffuse density. The difference is worth about one paper grade, which is why manufacturers publish different target contrast indexes for the two kinds of head.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/a-condenser-enlarger-produces-a-more-contrasty-print-from-the-same

### 3. Arrange the steps of making a print in the order they are carried out.

**Answer:**

1. Focus with the lens wide open, using a grain magnifier on the baseboard
2. Stop the lens down about two stops
3. Make a test strip in whole-stop steps
4. Choose the exposure from the test strip
5. Expose the full sheet
6. Develop for the full recommended time, then stop, fix and wash

**Why:** The last step is where beginners lose their blacks. Pulling a print when it looks right in the dish gives a grey, weak result, because the paper has not reached its full density; the correct response to a print that is coming up too dark is a shorter exposure next time, never a shorter development this time.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/arrange-the-steps-of-making-a-print-in-the-order-they-are-carried-out

### 4. Print exposures governed by the inverse-square law behave geometrically rather than arithmetically. Why does adding fixed increments of time, such as five seconds per strip, fail during test strip evaluation?

A. Equal linear additions yield diminishing changes in tonal density
B. Linear steps cause erratic shifts in grain sharpness and contrast
C. Fixed intervals make the paper receive exponentially runaway doses
D. Linear increments fail because development cannot reach completion

**Answer:** A. Equal linear additions yield diminishing changes in tonal density

**Why:** Tonal perception corresponds to logarithmic exposure stops. Adding fixed intervals yields progressively smaller proportional shifts, compressing highlight and shadow differences. Grain structure and full chemical development remain unaffected.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/print-exposures-governed-by-the-inverse-square-law-behave

### 5. Which are true of making a test strip?

A. Arithmetic steps of 5, 10, 15 and 20 seconds give uneven intervals in stops
B. Geometric steps of 4, 8, 16 and 32 seconds are one stop apart
C. The strip should be developed for the same full time as the final print
D. A test strip removes the need to consider the paper grade

**Answer:** A. Arithmetic steps of 5, 10, 15 and 20 seconds give uneven intervals in stops; B. Geometric steps of 4, 8, 16 and 32 seconds are one stop apart; C. The strip should be developed for the same full time as the final print

**Why:** The fourth is a category error. A test strip finds the exposure that puts the highlights where you want them; whether the shadows then fall where you want them is a contrast question, answered by the grade or the filtration. The two decisions interact and neither substitutes for the other.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/which-are-true-of-making-a-test-strip

### 6. Adding one third of a stop to a print exposure multiplies the time by what factor?

**Answer:** 1.26 (within ±0.06)

**Why:** **About 1.26**, the cube root of two. Two more such steps take you to 1.59 and then to 2.00, a whole stop. Working in thirds is what makes print exposures repeatable across sessions, because the increments mean the same thing whatever the base time happens to be.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/adding-one-third-of-a-stop-to-a-print-exposure-multiplies-the-time-by

### 7. An enlarging lens of 50 millimetres focal length is set to a magnification of 5. How far, in millimetres, is the lens from the paper?

**Answer:** 300 (within ±5)

**Why:** **300 millimetres.** The same relation puts the negative at 60 mm above the lens, since that distance is the focal length multiplied by one plus the reciprocal of the magnification. Between them these two figures are what decides whether a given enlarger column is tall enough for the print you want.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/an-enlarging-lens-of-50-millimetres-focal-length-is-set-to-a

### 8. An enlarging lens should be used wide open, so that the shortest possible exposure time is needed.

**Answer:** False

**Why:** **False** on both counts. Enlarging lenses are at their best about two stops down, where aberrations and corner falloff are controlled, and a very short exposure leaves no time for dodging or burning. Wide open is the focusing aperture; the working aperture is two stops below it.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/an-enlarging-lens-should-be-used-wide-open-so-that-the-shortest

### 9. Match each darkroom tool to its job.

**Answer:**

- Grain magnifier → Focusing on the grain itself at the baseboard, wide open
- Easel → Holding the paper flat and setting the borders
- Safelight → Light of a colour the paper cannot see
- Timer → Making an exposure repeatable from one sheet to the next

**Why:** The timer is the least glamorous and the most consequential. Everything in this lesson assumes exposures can be repeated to the second, and a printer counting under their breath cannot hold a third of a stop, which is exactly the increment the whole method is built on.

Page: https://tryals.app/practice/photography-i/the-enlarger-and-the-print/match-each-darkroom-tool-to-its-job