Skip to content

Operating Manual — TBS-001

The Big Shoebox Project — Camera No. 1 Single-operator workflow for cyanotype on cotton muslin.

Before you begin: Read this manual end-to-end once before your first deployment. Each phase has a time estimate and a GO/NO-GO checkpoint. Do not proceed past a checkpoint unless all conditions are met.

Quick Reference

Phase What Time
0 Pre-departure (home/workshop) ~2 hours
1 Site setup ~1.5 hours
2 Load image plane (red light) ~45 min
3 Exposure ~30–45 min (baseline)
4 Development ~20 min
5 Cleanup and close-down ~30 min
Total First print, ideal conditions ~5–5.5 hours

Baseline exposure is 30–45 minutes under direct full sun, ISO equivalent ~2–4. See the Exposure Adjustment Table for cloud cover and time-of-day corrections.

Phase 0 — Pre-Departure

Time: ~2 hours. Complete the day before or morning of shoot day at your workshop/home. Lighting: normal white light throughout this phase.

0.1 Water System

The water system has three circuits (Blue/Brown/Black), pumps on the plumbing panel in the IBC plumbing corridor (P-01 Blue supply, P-02 Brown filter feed, P-04 tray-sump transfer, plus the P-05/P-03 Brown/Waste drain pumps), and four 1,000L IBC totes in a 2×2 stack. All IBCs use DN50 butterfly valves facing the plumbing corridor; all tote-top connections are side-entry near the top (no top-cap access — only 52mm of headroom). The X1 fill line tees inside the corridor to fill both Blue totes (IBC-1 and IBC-2) in parallel via side-entry near the top. A check valve (CV-1) on the X1 fill line prevents backflow on the gravity fresh-fill; the pump-driven X3/X4 drains rely on the Shurflo pumps' integral check valves (CV-2/CV-3/CV-4 dropped as redundant). External fill (X1) and drain (X3/X4) ports on the sealed end wall allow resupply and disposal without opening the cargo doors.

  • [ ] 0.1.1 — Fill the Blue totes via external bulkhead port X1 (minimum 400 liters total for one print). X1 tees internally to fill both IBC-1 and IBC-2 in parallel. Confirm Brown IBC-3 and Waste IBC-4 are empty or have capacity.
  • [ ] 0.1.2 — Open isolation valve V1 (fill line) and VB1, VB2, VB3 (Blue outflow manifold). Prime P-01 by hand-filling the filter housing wet side.
  • [ ] 0.1.3 — Switch on P-01 Blue pump (circuit C). Pressure should reach 2.5–3.5 bar within 30 seconds.
  • [ ] 0.1.4 — Check all pipe joints for drips. Tighten any fittings that are weeping.
  • [ ] 0.1.5 — Run water through the spray bar for 60 seconds. Check spray pattern is even across the full image plane width.
  • [ ] 0.1.6 — Switch P-01 OFF.
  • [ ] 0.1.7 — Confirm P-04 suction pickup tube is seated in the sump well and the suction hose is connected over the tray rim to the pump manifold. Set 3W-DV-02 (on P-04 discharge) to route toward IBC-3 (Brown). P-04 draws used wash water from the sump and lifts it to IBC-3 via a side-entry near the top. Switch on manually after each wash cycle. (The tray and pickup tube are permanently installed between the film plane rails.)

0.2 Chemistry — Part A (Ammonium Iron(III) Oxalate)

Lighting: WHITE LIGHT — Part A is not light-sensitive in dry or dissolved form.

⚠ RECIPE NOT YET LOCKED — see Sensitizer Trials. Quantities use the Mike Ware New Cyanotype ratio (AmFe : ferricyanide = 3 : 1) over the 10.74 m² active plane, TWO wet-on-wet coats (§2.5), at the sourced muslin coverage ~120 ml/m²/coat → ~2.6 L working sensitizer per print. The concentration tier is the open variable — it swings chemistry cost and print count by ~3× across the three tiers. Three alternatives are given for costing/trialling. Default: Standard (½-Ware) until the trial decides.

Prepare Part A in warm water (50–60°C) — AmFe does not dissolve cold. Part A holds all the iron and is ~half the working volume (mixed 1:1 with Part B, §2.1).

Tier (per print) AmFe (dry) Part A water (warm) mixed strength AmFe for 50 prints
Lean (⅓-Ware) 260 g ~1.3 L 10 g/100 ml 13 kg
Standard (½-Ware) — default 390 g ~1.3 L 15 g/100 ml 19.5 kg
Rich (full-Ware) 780 g ~1.3 L 30 g/100 ml 39 kg
  • [ ] 0.2.1 — Heat water to 50–60°C (a kettle left to stand for 2 minutes after boiling is ideal).
  • [ ] 0.2.2 — Weigh AmFe into a mixing jug.
  • [ ] 0.2.3 — Pour warm water over the AmFe. Stir continuously until fully dissolved — the solution turns pale yellow-green and is clear, not cloudy. This may take 3–5 minutes.
  • [ ] 0.2.4 — Allow to cool to room temperature.
  • [ ] 0.2.5 — Label the jug PART A — AmFe (WARE). Store in a sealed dark bottle.

0.3 Chemistry — Part B (Potassium Ferricyanide + Ammonium Dichromate)

Lighting: WHITE LIGHT — Part B is not light-sensitive on its own.

Part B holds the ferricyanide (at ⅓ of the AmFe mass — Ware's 3:1 ratio) plus the ammonium dichromate contrast agent, in ~half the working volume. Dichromate is dosed as a % of the total working volume, so it is the same across strength tiers — Ware's baseline is 0.1%, increase for more contrast (trial T3: 0.1% / 0.2% / 0.4%).

Tier (per print) Potassium ferricyanide Ammonium dichromate (0.1–0.4%, trial) Part B water
Lean (⅓-Ware) 86 g 2.6–10.4 g ~1.3 L
Standard (½-Ware) — default 130 g 2.6–10.4 g ~1.3 L
Rich (full-Ware) 260 g 2.6–10.4 g ~1.3 L
  • [ ] 0.3.1 — Weigh potassium ferricyanide and ammonium dichromate into a second jug.
  • [ ] 0.3.2 — Add water (room temperature). Stir until fully dissolved — the solution turns bright orange-red.
  • [ ] 0.3.3 — Label the jug PART B — KFe + AmDichr.

⚠ Ammonium dichromate is a Category 1A carcinogen. Wear nitrile gloves when handling dry powder. Do not inhale dust. The small quantity used here (~10g per print) is well within safe handling range for a ventilated workspace.

Storage: Part A and Part B stock solutions keep for 6–8 weeks in sealed dark bottles. Mixed together (the working sensitizer), shelf life is 4–6 hours. Mix only what you need per session.

0.4 Equipment Checklist

  • [ ] 0.4.1 — Nitrile gloves (minimum 4 pairs)
  • [ ] 0.4.2 — 18" foam roller + roller tray (two sets — one per coat pass)
  • [ ] 0.4.3 — 2 × 2-liter mixing jugs (graduated)
  • [ ] 0.4.4 — Funnel and stirring rod
  • [ ] 0.4.5 — Digital scale (1g resolution)
  • [ ] 0.4.6 — Digital hygrometer
  • [ ] 0.4.7 — Pre-cut muslin in light-safe bag (unbleached cotton, 5900 × 2,400mm with 100mm hem allowance)
  • [ ] 0.4.8 — Part A bottle (sealed, labeled)
  • [ ] 0.4.9 — Part B bottle (sealed, labeled)
  • [ ] 0.4.10 — Timer (phone or dedicated)
  • [ ] 0.4.11 — Spirit level
  • [ ] 0.4.12 — Black silicone sealant + gaffer tape (light-leak repair)

0.5 Container Pre-Check (if accessible)

  • [ ] 0.5.1 — Inspect interior: no water ingress or condensation on image plane.
  • [ ] 0.5.2 — All seals (door perimeter, neoprene cord) are intact.
  • [ ] 0.5.3 — Film plane mechanism moves freely on all four corners.
  • [ ] 0.5.4 — Install perimeter walkway grating sections onto wall-cantilevered brackets around all 4 sides of the processing tray. Near, far, and right grating panels lift onto bracket arms and are secured with grating clips. The left walkway (cargo door end) is a removable lift-out section — it rests on 5 floor-leg cantilever brackets bolted to the bare floor outside the tray (the three brackets at the drum-exit punch-out reach further inboard than the rest; the hinged panel occupies this end wall). Left corners use butt joints (no miter) so near/far walkways start clear of the door-end panel swing sweep. The left walkway grate must be removed before the panel swings to its transport position; the floor brackets stay bolted. No contact with the tray (brackets sit on bare floor outside it).
  • [ ] 0.5.5 — Lay fresh 6-mil black LDPE containment liner over the tray surface, overlapping 50mm over the rims.

GO/NO-GO checkpoint: Water system tested and IBCs filled. Part A and Part B prepared and sealed. All equipment packed. Container interior inspected (if accessible).

Phase 1 — Site Setup

Time: ~1.5 hours. Complete on arrival at site. Lighting: normal white light / daylight.

1.1 Site Selection

  • [ ] 1.1.1 — Ground is level to within 5° (use a spirit level on the container floor after delivery).
  • [ ] 1.1.2 — Subject is visible from the pinhole wall — nothing blocking the view within 5m.
  • [ ] 1.1.3 — Shade structure can be erected over the container (trees, canopy, building shadow).
  • [ ] 1.1.4 — Solar panel deployment area: clear southern exposure, ~4m × 3m.
  • [ ] 1.1.5 — Water source within 20m, or tanker access for IBC tote fill (if not pre-filled).
  • [ ] 1.1.6 — Emergency vehicle access not blocked by container placement.

1.2 Container Positioning

  • [ ] 1.2.1 — Direct the delivery driver to position the container with the cargo doors at 90 degrees from the subject. The pinhole wall faces the subject.
  • [ ] 1.2.2 — Once set down, check level. Use 50mm timber sleepers under corner castings to correct — up to 50mm height difference is manageable without shimming the mechanism.
  • [ ] 1.2.3 — Open cargo doors and inspect interior (if not done in Phase 0.5).

1.3 Mode Conversion — Transport to Operational

Time: ~5 minutes. Single-person operation.

The container arrives in transport mode: the stepped hinged panel is swung ~56° inboard about the vertical pivot post and held by the top + bottom wall stays; the two left film rails (TL + BL) and the left walkway have been struck/removed. Convert to operational mode before proceeding.

  • [ ] 1.3.1 — Open and secure the cargo doors.
  • [ ] 1.3.2 — Release the top + bottom wall stays: slack the turnbuckles and unhook the rods from the near-wall eyes.
  • [ ] 1.3.3 — With the panel still swung clear of the door plane, retrieve the evaporative cooler from near-walkway stowage (release 2 ratchet straps) and carry it out through the door opening (~20 kg dry, one person).
  • [ ] 1.3.4 — Place the cooler on the ground outside the container, adjacent to the pinhole wall near the Ø200mm duct penetration. Remove the weatherproof cap from the wall stub. Connect the Ø200mm flex duct from the cooler outlet to the wall stub collar and secure with a hose clamp. Fill the reservoir (~18 L, one tankful) from the Blue circuit at TAP-01 on the pinhole wall — doors are open at this stage, so draw at TAP-01 and carry/hose the water out to the cooler.
  • [ ] 1.3.5 — Swing the frame back ~56° to the door plane (camera position), assisted. The vertical pivot is balanced at any angle (no gravity torque) — effort is only inertia + bearing friction; control momentum at the stop.
  • [ ] 1.3.6 — Latch the panel to the door frame with all 4 Southco cam latches (quarter-turn, flush with panel face) — compresses the EPDM perimeter + cut seals.
  • [ ] 1.3.7 — Re-fit the two left film rails (TL + BL): drop each into its saddles; the tapered dowels set the film datum; clamp down. Confirm the re-seated rails return the film plane square and planar to datum.
  • [ ] 1.3.8 — Re-fit the left walkway + door-end near-deck lift-out section onto their butt-joint ends / floor-leg cantilever brackets.
  • [ ] 1.3.9 — Un-pin the revolving drum (ready for personnel light-lock use).
  • [ ] 1.3.10 — Perform dark-adaptation check (see step 1.4.4 below).

1.4 Light Trap — Revolving Drum Panel

  • [ ] 1.4.1 — Confirm the hinged drum panel is closed and all four Southco cam latches are engaged (quarter-turn, flush with panel face).
  • [ ] 1.4.2 — Check the EPDM perimeter gasket is seated with no gaps or folded sections.
  • [ ] 1.4.3 — Rotate the drum one full revolution by hand — it should turn freely with no binding or scraping.
  • [ ] 1.4.4 — Verify: step into the drum entry side and rotate through to the interior. Wait 2 minutes for dark adaptation. No light should be visible at any baffle position. Mark any leaks with chalk and seal with black silicone before proceeding.

Safety: Do not attempt to reverse direction inside the drum — the baffles only clear forward rotation. If unsure of orientation, continue rotating forward until you exit on the intended side.

1.5 Solar Power System

  • [ ] 1.5.1 — Deploy solar panels on south-facing ground or roof rack, angled at 30° from horizontal (optimal for Palm Springs latitude).
  • [ ] 1.5.2 — Connect panels in parallel to the Victron SmartSolar MPPT 100/50 controller.
  • [ ] 1.5.3 — Connect controller to battery bank (2 × 100Ah LiFePO4 in parallel). Observe polarity.
  • [ ] 1.5.4 — Connect Blue Sea fuse block to battery positive busbar.
  • [ ] 1.5.5 — Check controller display: battery voltage should read 12.6–13.2V (full charge). If below 12.0V, charge before proceeding — a depleted battery bank cannot power the cooler and water system simultaneously.
  • [ ] 1.5.6 — Verify each circuit fuse is seated: A (exhaust fan), B (intake fan), C (water pumps P-01–P-04), D (safelight), E (evap cooler), F (actuators, if fitted).

Shore power backup: If grid power is available at the site, connect the Victron IP65 charger to the NEMA 5-15 inlet on the container exterior. The charger maintains the battery bank automatically — leave it connected whenever shore power is available.

1.6 Ventilation and Cooling

  • [ ] 1.6.1 — Switch ON exhaust fan (circuit A) and intake fan (circuit B). Confirm airflow — hold a piece of tissue at each duct stub; it should deflect visibly.
  • [ ] 1.6.2 — Cooling (hot climate): Switch ON evaporative cooler (circuit E). Fill cooler reservoir. Run cooler for a minimum of 30 minutes before any operator entry when ambient temperature exceeds 30°C. Interior should reach below 35°C before loading.
  • [ ] 1.6.3 — If using shade canopy: erect before solar noon. An 80% shade cloth over the container reduces interior temperature by 15–20°C.

Heat safety: Do not enter the container if the interior temperature exceeds 40°C. A digital thermometer hung inside is standard practice. In Palm Springs summer without shade, the steel container body can reach 75°C — shade and pre-cooling are not optional in these conditions.

1.7 Walkway and Tray (if not done in Phase 0.5)

  • [ ] 1.7.1 — Install perimeter walkway grating sections (see 0.5.4 for full procedure).
  • [ ] 1.7.2 — Lay fresh LDPE containment liner (see 0.5.5).

1.8 Light-Leak Inspection

  • [ ] 1.8.1 — Latch the drum panel (all four Southco cam latches engaged).
  • [ ] 1.8.2 — Switch ON interior safelight (circuit D, red LED only). Enter through the revolving drum.
  • [ ] 1.8.3 — Switch OFF safelight. Stand still for 15 minutes minimum — full dark adaptation.
  • [ ] 1.8.4 — Inspect all seams, door perimeters, and duct penetrations. Even a pinprick leak will be visible.
  • [ ] 1.8.5 — Exit. Seal any leaks found with black silicone sealant or gaffer tape. Repeat inspection.

GO/NO-GO checkpoint: All leaks sealed. Interior temperature below 35°C. Battery bank above 12.4V. Water system pressure confirmed.

Phase 2 — Loading the Image Plane

Time: ~45 minutes. Entire phase performed under RED LIGHT only (circuit D). Lighting: RED LED safelight. No white light, no daylight.

2.1 Prepare Working Sensitizer

Do this step just before entering — the combined sensitizer is UV-sensitive.

For 1 print (10.74 m² active plane, 2 wet-on-wet coats) Volume
Part A ~1.3 L
Part B ~1.3 L
Working sensitizer ~2.6 L

Volume basis: ~120 ml/m²/coat (muslin, sourced — AlternativePhotography / Jacquard) × 2 coats (§2.5 is two wet-on-wet passes, not one) × 10.74 m². Confirm by trial T1 — Sensitizer Trials. Mix 1:1 by volume.

  • [ ] 2.1.1 — Pour equal volumes of Part A and Part B into a third jug. Stir gently. The mix turns yellow-green.
  • [ ] 2.1.2 — Pour into the roller tray immediately.

The mixed sensitizer is UV-sensitive. It is safe under red LED safelight but must not be exposed to daylight, blue sky light, or white LED light once mixed. Work quickly once inside.

2.2 Humidity Check

Cyanotype coating is sensitive to humidity. Check with a digital hygrometer:

Humidity Action
Below 30% (typical Palm Springs) Mist the muslin lightly with plain water 5 min before coating
30–65% Coat normally
Above 70% Delay — coating may not dry under safelight, increasing fogging risk
  • [ ] 2.2.1 — Check humidity and take appropriate action per table above.

2.3 Entering via the Light Trap

Revolving drum entry procedure (memorize this — you will do it in dim conditions):

  • [ ] 2.3.1 — Confirm drum panel is latched (all four Southco cam latches engaged).
  • [ ] 2.3.2 — Carry all equipment to the drum entry side. Set it down at your feet.
  • [ ] 2.3.3 — Push the drum wall forward until the first baffle clears. Step in.
  • [ ] 2.3.4 — Continue rotating forward until you exit into the container interior.
  • [ ] 2.3.5 — Pass equipment through the drum in the same direction — one item at a time.
  • [ ] 2.3.6 — Switch ON the safelight (circuit D switch, located on the electrical panel). RED light only.

Rule: The drum seals automatically as it rotates — no doors to leave open. However, do not wedge equipment in the drum aperture. If a load is too large for the drum, it must be loaded during a full dark period (after sunset) with the panel unlatched and swung open.

2.4 Mounting the Muslin

  • [ ] 2.4.1 — Retrieve the pre-cut muslin.
  • [ ] 2.4.2 — Start at the bottom edge of the image plane frame. Flip each cam-lever clamp open, slide the muslin hem under the jaw, then flip the lever closed — the over-center cam snaps shut with tactile feedback, gripping at ~5N. Work along the bottom edge at 150mm centers (30 clamps).
  • [ ] 2.4.3 — Work upward — stretch the fabric taut and clamp the top edge (30 clamps). The torsion spring holds each clamp closed at any tilt angle.
  • [ ] 2.4.4 — Clamp the left and right edges (16 clamps each), pulling outward from center. Total: 92 clamps around the full perimeter.
  • [ ] 2.4.5 — Final check: no wrinkles or sags when viewed with the safelight from 2 meters. Any slack will print as a soft zone.

2.5 Applying the Sensitizer

Lighting: RED LED safelight only. Work efficiently — aim to complete coating within 20 minutes.

  • [ ] 2.5.1 — Load the foam roller with sensitizer. Roll out any excess onto scrap card — the roller should be evenly loaded, not dripping.
  • [ ] 2.5.2 — First coat: roll horizontally from left to right across the full width of the muslin. Even strokes, 50% overlap. Work top to bottom.
  • [ ] 2.5.3 — Second coat — wet-on-wet (apply while the first is still wet): roll vertically, top to bottom. The cross-direction second coat lays down the remaining sensitizer and evens the coverage. Two coats is why the working volume is ~2.6 L (§2.1), not ~1.3 L — budget for both.
  • [ ] 2.5.4 — Check edges — roller tends to undercoat at the far edges. Finish with a hand-held foam brush on the last 50mm of each edge.
  • [ ] 2.5.5 — Set the empty tray and roller aside. Do not leave the roller sitting in residual sensitizer — it will skin over.

2.6 Tack-Drying

Lighting: RED LED safelight only.

  • [ ] 2.6.1 — Run the ventilation fans (circuits A and B) on low speed — just enough airflow to assist drying. Avoid directed airflow directly at the coated surface.
  • [ ] 2.6.2 — Wait 15–20 minutes under safelight. The sensitizer changes from wet-glossy to a matte tack-dry state.
  • [ ] 2.6.3 — Confirm by lightly touching the corner of the coated area with a gloved fingertip. It should not transfer to the glove.

Do not proceed with a wet coat. A wet coat will run during exposure and will not produce a sharp image.

2.7 Exiting via the Light Trap

  • [ ] 2.7.1 — Switch OFF safelight.
  • [ ] 2.7.2 — Step into the drum from the interior side. Rotate forward (same direction as entry) until you exit to the exterior.
  • [ ] 2.7.3 — The drum seals behind you as it rotates.

GO/NO-GO checkpoint: Muslin fully clipped and taut. Sensitizer dry to touch. Drum panel latched.

Phase 3 — Exposure

Time: ~30–45 minutes baseline + adjustment (Ware formula). Shutter operated entirely from outside. Lighting: N/A — operator is outside the container.

3.1 Exposure Calculation

Baseline exposure: 30–45 minutes in direct unobstructed sun, mid-morning to mid-afternoon, summer (Mike Ware New Cyanotype formula on cotton muslin). This is 4–8× faster than the traditional Herschel formula (~2–3 hours baseline) due to the higher UV sensitivity of ammonium iron(III) oxalate.

Exposure Adjustment Table

Condition Multiply baseline by
Full direct sun × 1.0
Thin haze / milky sky × 1.5
Broken cloud (50% coverage) × 2.0
Heavy overcast × 4.0
Early morning / late afternoon (2h before/after sunset) × 2.0
Winter sun at mid-latitude × 1.5

For compound conditions (e.g. thin haze + early morning), multiply the factors: 1.5 × 2.0 = × 3.0.

These factors are EV-based estimates for light level changes. Cyanotype is an iron-based process and does not exhibit Schwarzschild reciprocity failure — no additional reciprocity correction is required beyond the factors above. For critical work, run a test strip first: cut a 200mm × full-height strip of coated muslin, expose in 5-minute intervals using a card mask, develop immediately, and compare zones.

3.2 Opening the Shutter

  • [ ] 3.2.1 — Confirm the vestibule outer door is closed and latched.
  • [ ] 3.2.2 — Set a timer for your calculated exposure time.
  • [ ] 3.2.3 — Open the pinhole shutter from the exterior operating handle.
  • [ ] 3.2.4 — Do not open any doors, stand in front of the pinhole wall, or allow shadows to cross the pinhole during exposure.

3.3 Monitoring During Exposure

  • [ ] 3.3.1 — Check the battery bank voltage on the MPPT controller display every 15 minutes. If voltage drops below 11.8V, switch off the evaporative cooler (non-essential during exposure).
  • [ ] 3.3.2 — Note any significant cloud cover changes. If conditions change substantially mid-exposure (e.g. sky goes from clear to heavy overcast), close the shutter, note elapsed time, wait for conditions to return, then re-open for the remaining time.

3.4 Closing the Shutter

  • [ ] 3.4.1 — At the calculated time, close the pinhole shutter using the exterior operating handle.
  • [ ] 3.4.2 — Verify the shutter indicator reads CLOSED before entering.

GO/NO-GO checkpoint: Shutter confirmed closed. Elapsed time within ± 2 min of target.

Phase 4 — Development

Time: ~20 minutes. Lighting: RED LED safelight on entry, then switch to WHITE LIGHT after first wash begins.

4.1 Entering and Removing the Muslin

  • [ ] 4.1.1 — Enter via light trap (same procedure as Phase 2.3). Switch safelight ON (red light).
  • [ ] 4.1.2 — Flip each cam-lever clamp open to release the muslin — work top-down, supporting the fabric weight as the upper clamps release. The image is latent at this point and may be barely visible as a pale yellow ghost.
  • [ ] 4.1.3 — Lay the muslin face-up on the LDPE containment sheet on the processing zone floor (optical zone, between the film plane rails).

4.2 Development in Water

Lighting: switch to WHITE LIGHT (circuit D, white mode) once the first wash begins — the image is no longer UV-sensitive after initial water contact.

Cyanotype develops by oxidation — the iron salts convert to Prussian blue on contact with water and air. The full blue color deepens over the first few minutes of drying.

Spray bar setup:

  • [ ] 4.2.1 — Position the spray bar at the far end of the tray (Yd≈2,280mm, film-plane side). Attach the telescoping pole to the arm tube.

Wash sequence using the Blue circuit:

  • [ ] 4.2.2 — Switch ON P-01 Blue pump (circuit C). Confirm VB1, VB2, VB3 are open.
  • [ ] 4.2.3 — Open BV-02. Using the pole, slowly pull the spray bar toward the pinhole wall (decreasing Yd), flooding the print progressively. Travel speed ~50mm/second — full traverse takes ~44 seconds. At the near rim (Yd≈80mm), close BV-02. Push the bar back to the far end and repeat. Allow water to flow over the full surface for 5 minutes. The wash water will run yellow-green as unreacted sensitizer clears. This is normal and non-toxic. Switch to WHITE LIGHT now — the print is safe once washing begins.
  • [ ] 4.2.4 — Close BV-02. Switch ON P-04 to pump wash water from the sump up to IBC-3 (Brown recovery) via 3W-DV-02. If the first rinse is heavily contaminated, set 3W-DV-02 to divert to IBC-4 (Waste) instead.
  • [ ] 4.2.5 — For the second wash pass, close BV-02 and activate P-02 through the filter train. Recycled Brown water from IBC-3 is pumped through the three-stage filter skid and back into the spray bar via the same supply path. Repeat the spray bar traverse.
  • [ ] 4.2.6 — Repeat for a total of 3 wash cycles (15 minutes total). Subsequent rinses route to IBC-3 (Brown) for recycling via the filter skid.
  • [ ] 4.2.7 — Final rinse: open BV-02 for a 2-minute final flush with clean Blue water. Drain via P-04 to IBC-3.

Visual check after the second wash: The image should be clearly visible — Prussian blue shadows against a white or off-white highlight. If the image appears flat or very faint, the print was underexposed. Allow it to complete washing and dry — images that appear pale when wet frequently darken significantly on drying. If still flat after drying, re-expose for 1.5× the original time.

Valve matrix

Valve Default Wash 1 Drain 1→Brown Wash 2 (recycled) Drain 2→Brown Wash 3 Drain 3
BV-01 (Blue manifold) Open Open Open Open Open Open Open
BV-02 (Blue to floor) Closed Open Closed Closed Closed Open Closed
BV-06 (Chem tap) Closed Closed Closed Closed Closed Closed Closed
3W-DV-02 (tray drain) Brown Brown Brown Brown Brown Brown Brown
P-02 (Brown pump) Off Off Off On Off Off Off
3W-DV-01 (filter out) Blue return Blue Blue Blue Blue Blue Blue

Diverter valve operator decisions

The two 3-way diverter valves serve different roles in the water triage chain. Understanding when and why to switch each valve is critical to avoiding cross-contamination of the Blue clean supply.

3W-DV-02 — Tray drain diverter (operator judgment call)

DV-02 sits on the P-04 pump discharge and controls whether drain water from the processing tray goes to Brown (IBC-3, for filtering and potential recycling) or Black (IBC-4, waste for external disposal). There is no automated test at this valve — the operator decides based on what happened during the session:

  • Set to Brown (default): Normal processing rinse water. The water contains only trace amounts of residual cyanotype chemistry (ferric ammonium oxalate and potassium ferricyanide) from the print surface. This water is suitable for filtering and potential recycling back to Blue.
  • Switch to Black: Heavy contamination events — concentrated chemistry spills, failed sensitizer coating that washes off in bulk, or any situation where the drain water is visibly discolored beyond a pale yellow tint. This water goes directly to IBC-4 for external disposal and never enters the filter/recycle path.

Rule of thumb: If the drain water looks like rinse water (clear to pale yellow), send it to Brown. If it looks like chemistry (deep yellow, orange, or green), send it to Black.

3W-DV-01 — Filter output diverter (pH meter reading)

DV-01 sits after the filter skid (F1→F2→F3) and the SV-01 sample tap. After brown water has been filtered, the operator draws a ~50 ml sample at SV-01 and checks the pH reading:

  • Set to Blue return (default): pH is between 6.5 and 8.0, indicating the filtered water is chemically neutral enough to return to IBC-2 (Blue clean supply) for reuse.
  • Switch to Black: pH is outside the acceptable range, or the water is visibly discolored after filtering. This water goes to IBC-4 (waste) rather than contaminating the clean supply.
Valve Decision Basis Who decides
3W-DV-02 (tray drain) Brown vs Black Contamination severity at drain time Operator — visual judgment
3W-DV-01 (filter output) Blue vs Black Water quality after filtering Operator — pH meter reading

4.3 Drying

Lighting: WHITE LIGHT or daylight — cyanotype is no longer light-sensitive after washing.

  • [ ] 4.3.1 — After the final wash, carry the muslin outside through the light trap. Daylight exposure is safe and accelerates oxidation.
  • [ ] 4.3.2 — Hang the developed muslin to dry — horizontal is ideal (prevents drip marks). Wooden poles or a rope line between two vehicles work well.
  • [ ] 4.3.3 — Drying time: 20–60 minutes depending on temperature and airflow. The blue intensifies as the image oxidizes in air.
  • [ ] 4.3.4 — Final color appears approximately 30 minutes after the print appears dry to the touch.

Extended Deployment — On-Site Water Top-Up (optional)

Lighting: normal — all top-up is external; the container stays sealed and dark.

A single hauled Blue fill supports ~14 prints (or ~15–16 if the Blue totes were topped toward their ~1,900–2,000L maximum before departure — see Water System Report §4). For a longer stay, resupply Blue and discharge waste through the external end-wall bulkhead ports — without opening the cargo doors, so the dark, camera-ready state is preserved and the print cycle (Phases 2–4) simply repeats. This is a distinct mode from the single-fill deployment; it is not required for a normal 1–2 print outing.

  • [ ] TU.1 — Watch the Blue low-level float (IBC-2) alert. Plan a top-up before it runs dry mid-wash, not after.
  • [ ] TU.2 — Resupply Blue: connect the water bowser/tanker hose to the external X1 camlock inlet on the sealed end wall. Open isolation valve V1; X1 gravity-feeds and tees to both Blue totes in parallel (side-entry near the top). Confirm the level, then close V1 and disconnect.
  • [ ] TU.3 — Discharge Brown/Waste when they near their working levels: connect a disposal tanker or holding tank to the X3 (Brown) and/or X4 (Waste) camlock ports, then run P-05 (X3) / P-03 (X4) to pump out. Close and re-cap the ports when done.
  • [ ] TU.4 — With supply restored and collection capacity freed, resume the print cycle from Phase 2. Print count per deployment is now set by water logistics (bowser visits, disposal access), not tote volume.

Before transport: return the totes to their validated fill states — Blue drained, Waste within its return-haul limit — per §5.5. On-site top-up does not change the transport fill limits.

Phase 5 — Cleanup and Close-Down

Time: ~30 minutes. Lighting: WHITE LIGHT.

5.1 Chemistry Disposal

  • [ ] 5.1.1 — Spent wash water (yellow-green): cyanotype wash water at this dilution is non-hazardous. It is collected in IBC-3 (Brown) for recycling through the filter skid (P-02 → F-1/F-2/F-3), or diverted to IBC-4 (Waste) if heavily contaminated. Waste IBC-4 contents are drained via external port X4 to a disposal tanker. Do not dispose into storm drains without verification of local regulations.
  • [ ] 5.1.2 — Unused sensitizer: seal and store in a dark bottle (4-week shelf life for separated A and B solutions). Mixed working sensitizer: discard — working life is 6 hours.
  • [ ] 5.1.3 — Rinse all trays, rollers, and brushes in plain water immediately. Dried sensitizer is harder to remove.
  • [ ] 5.1.4 — Stow the spray bar at either end of its travel. Detach the telescoping pole and store alongside the bar or clip to the container wall. The flexible hose coils naturally at the pinhole wall.

5.2 Container Ventilation

  • [ ] 5.2.1 — Open both ventilation fans to full speed (circuits A and B).
  • [ ] 5.2.2 — Leave ventilating for 30 minutes minimum after development is complete, especially if working in hot conditions — the container interior will have accumulated heat and humidity from the wash operation.

5.3 Power-Down Sequence

Power down in this order to avoid voltage spikes on sensitive electronics:

  • [ ] 5.3.1 — Evaporative cooler (circuit E)
  • [ ] 5.3.2 — Water pumps P-01 through P-04 (circuit C)
  • [ ] 5.3.3 — Ventilation fans (circuits A, B)
  • [ ] 5.3.4 — Safelight (circuit D)
  • [ ] 5.3.5 — Film plane actuators if used (circuit F)
  • [ ] 5.3.6 — Disconnect solar panel inputs at the MPPT controller

If shore charger is connected, leave it running overnight to top up the battery bank.

5.4 Securing the Container (Operational Mode)

  • [ ] 5.4.1 — Engage all four Southco cam latches on the drum panel.
  • [ ] 5.4.2 — Apply secondary locking bar across the drum panel face if the container will be unattended overnight.
  • [ ] 5.4.3 — Cap all ventilation duct stubs on the exterior.
  • [ ] 5.4.4 — Secure solar panels — if conditions allow, lay flat or fold to minimize wind load.

5.5 Transport Mode Conversion (Packing Up)

Time: ~5 minutes. Single-person operation.

The stepped hinged panel + drum SWING ~56° inboard about the vertical pivot post for transport, riding the floor gap (clearing the processing tray rim). The two left film rails (TL + BL) and the left walkway must be removed before the swing so the drum cage can transition the left film-plane rail plane. The processing tray and the near/far/right walkway sections remain in place during mode conversion.

  • [ ] 5.5.1 — End camera use: power off Fan B, finish any darkroom access. Stow all interior items; return the film-plane cross-slides to their datum.
  • [ ] 5.5.2 — Park the revolving drum in its closed/aligned position and pin its rotation (detent) so it cannot flop during the move.
  • [ ] 5.5.3 — Disconnect the flex duct from the wall stub collar (release hose clamp). Replace the weatherproof cap on the wall stub. Drain the cooler reservoir completely.
  • [ ] 5.5.4 — Carry the cooler in through the door opening (~20 kg, one person). Place on a ply base plate on the near-walkway wide section, clear of the panel swing sweep. Secure with 2× ratchet straps to the wall brackets. Stow the flex duct alongside.
  • [ ] 5.5.5 — Lift out the removable left walkway + door-end near-deck section — both sit inside the swing arc.
  • [ ] 5.5.6 — Strike the two left film rails (TL + BL): release each clamp bar, lift the rail straight up out of its saddles, and stow (clipped to the near wall). Required before the swing — otherwise the drum cage fouls the left rail plane.
  • [ ] 5.5.7 — Release all 4 Southco cam latches — releases the perimeter + cut seals.
  • [ ] 5.5.8 — Swing the frame ~56° inboard (toward the far wall), assisted. Balanced about the vertical pivot (no gravity torque); control momentum at the stop.
  • [ ] 5.5.9 — Engage the transport lock: connect the top + bottom wall stays — hook the rods from the frame hooks to the near-wall eyes and tension the turnbuckles.
  • [ ] 5.5.10 — Close and latch the standard ISO container cargo doors. They close outboard of the fixed left panel (Yd0–180); the swung frame clears the door plane by +59 mm.

5.6 Operational Mode Conversion (Setting Up)

Time: ~5 minutes. Single-person operation. Reverse of 5.5.

Follow the procedure in Phase 1.3 — Mode Conversion. Steps are the reverse of §5.5: open cargo doors → release wall stays → swing the panel back ~56° to the door plane → latch panel → re-fit the left film rails + left walkway → place cooler on ground and connect flex duct → un-pin drum → dark-adaptation check.

Exposure Adjustment Table

Full reference table for use in Phase 3.

Baseline 35 min Direct full sun, summer, 10:00–14:00 (Ware formula)
Thin haze 55 min
Broken cloud 70 min
Heavy overcast 140 min
Early/late sun 70 min
Winter mid-latitude 55 min
Thin haze + early sun 105 min Multiply factors: 1.5 × 2.0

Troubleshooting

Symptom Likely cause Action
Image very faint after full drying Underexposure Increase time by 50%
Image too dark / no highlight detail Overexposure Reduce time by 30% on next print
Streaks or tide-marks Uneven coating or drips during development Improve roller technique; ensure even wash flow
Soft or blurred image Muslin slack at coating or during exposure Increase clip tension; check frame is not vibrating in wind
Blue haze (fogging) in shadows Light leak or sensitizer exposed to UV before loading Re-inspect light trap; check sensitizer storage
Uneven color — cool/warm zones Humidity variation across coating Ensure even pre-misting if in dry climate

See Also