ROLLVECTORPRECISION DARKROOM ATELIER
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LAB 01 / MEDIUM FORMAT / 120

Every roll has
a direction.

Learn the path. Save the roll.
A hands-on laboratory for 120 film orientation and loading.

BEFORE YOU OPEN THE BACK

Practice here.
Keep your real film safe.

2 camera profiles · No sign-in · Free to explore
LIVE FILM WORKBENCHSIMPLIFIED EDUCATIONAL MODEL / V.1.0
HASSELBLAD A12 / UNFOLDED PATH↑ LENS SIDE
120 film transport learning diagramAn unfolded schematic, not a to-scale camera interior. Two spools, film gate and paper layers respond to the loading controls.FILM GATE120 / SUPPLYSTARTEMULSION → LENSPAPER → BACKCLAMP—ROLLVECTOR / 120SUPPLY / FRESH ROLLTAKE-UP / EMPTY SPOOL
UNFOLDED TRANSPORT SCHEMATIC · NOT TO SCALE
Backing paperFilm layer△ Start index
Progress stays in this browser

01 / FILM ANATOMY

One roll. Several layers.

The light-sensitive side faces the lens. The backing paper protects the rear.

↓ LIGHT FROM LENS
Light-sensitive emulsion
Film base
Backing paper — 120
Conceptual cross section; layer thickness exaggerated.

120 is a film type, not a frame count.

120 roll film has backing paper along the film. The leader is paper before the imaging area. Handle the outer paper and keep the roll tight. Do not peel the film apart in room light.

120 ≠ 220

Traditional 220 uses paper at the ends rather than continuous backing paper. Length, pressure plate and counter compatibility matter. Do not assume a 120 holder accepts 220.

02 / MISTAKE LAB

Make the mistake here.

Observe a risk scenario, then repair the virtual setup.

ANOMALY REPORT

A safe place to be wrong.

Select a scenario. These are possible outcomes, not predictions of which exact frame will be damaged.

01020304

03 / ROLL RESCUE

Something feels wrong?

Start with the symptom. Keep the back closed.

A troubleshooting aid, not a mechanical diagnosis.

04 / FORMAT EXPLORER

Same roll. Different windows.

Nominal formats; actual image dimensions and counts vary by camera.

12 frames / roll
123456789101112

Common counts: 6×4.5 ≈ 15–16; 6×6 ≈ 12; 6×7 ≈ 10; 6×9 ≈ 8. Changing this explorer does not change your camera mask.

05 / POCKET LOADING CARD

Take the sequence with you.

ROLLVECTOR

Hasselblad A12 / 120 · 6×6

  1. Open the magazine — Remove the matched insert; keep the dark slide in an unattached magazine.
  2. Seat the spools — Put the empty spool on the take-up side. Seat the fresh 120 roll on the supply side.
  3. Thread the leader — Guide the backing paper under the film clamp and engage the tapered tip in the take-up slot.
  4. Align the start arrow — Turn the insert knob clockwise until the backing-paper arrow meets the triangular index. Stop at the mark.
  5. Close and lock — Reinsert the holder into its matched shell and lock it.
  6. Advance to frame 1 — Turn the external winding crank until it stops at 1. Return the crank.

△ Load in subdued light. Never open a partly exposed roll in daylight. Follow the exact model’s manual; this card is a reminder, not a service manual.

06 / REFERENCE LIBRARY

Read the mechanism.

MAGAZINE / A12

The arrow is a starting reference.

A12 loading separates two actions: align the paper mark on the insert, then close the magazine and advance its external mechanism to frame 1. The index is not a frame number. A12 versions differ; match the manual to the magazine.

Hasselblad camera manual (PDF) ↗
RED WINDOW / HOLGA

Match the mask and the window.

The Holga 120N uses the numbers printed on the backing paper. The window selector must match the chosen mask. The live exercise uses 6×6; other format options are reference comparisons.

Holga supplied manual ↗
METHOD / EDITORIAL

A model with clear boundaries.

The workbench is an unfolded teaching schematic. It does not reproduce exact roller geometry, tension, frame spacing or physical camera orientation. Path and X-ray views teach relationships. Follow source diagrams for actual placement.

Reviewed 3 November 2026 · Independent educational project

07 / FREQUENT QUESTIONS

Before the next roll.

Which side of 120 film faces the lens?

The light-sensitive emulsion faces the lens at the exposure gate. Backing paper lies behind the film. Follow the full route in your camera manual rather than guessing from spool appearance.

Can I fix a missed start arrow by winding backwards?

Do not assume reverse winding is supported. Stop and consult the exact manual. If film may be exposed, keep the back shut and get help in a changing bag or darkroom. Virtual Undo is not a real-camera instruction.

Does the simulator support every medium format camera?

No. This release teaches A12 and Holga 120N loading principles. Rolleiflex feeler rollers, RB67 holders and other cameras require separate verified profiles. Do not apply the same path to them.

Where is my progress stored?

Only in this browser’s local storage when available. No account or upload is needed. Reset clears the current exercise. Clearing browser data removes saved progress. Advertising services may use their own cookies.