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TBS-002 — Mini-TBS Shopping List

Complete itemized list for building the Mini-TBS proof-of-concept camera (two-box design) and making 20 cyanotype prints on watercolor paper. All quantities include 25% overage for waste and practice.

Target budget: $129–$195 (see summary at bottom).

1. Box and Construction

Item Qty Supplier 1 Price Supplier 2 Price Notes
Medium moving box (18×18×16") 2 U-Haul $4.50 ea Home Depot $3.98 ea One camera box + one prep box
Black duct tape, 2" × 30 yd 1 roll Home Depot $5.98 Dollar Tree $1.25 Light sealing, hinges, sleeve attachment — one roll covers the entire build
Foam-core board, 20×30" 1 sheet Dollar Tree $1.25 Walmart $2.98 Cut to ~17.5×15.5" for hinged backing board

Subtotal: $11–$16

2. Pinhole Materials

Item Qty Supplier 1 Price Supplier 2 Price Notes
Aluminum beverage can 1 — Free — Free Empty, clean, dry. Use flat side wall.
1/32" (0.794mm) drill bit 1 Home Depot (Milwaukee) $3.97 Ace Hardware $4.49 HSS twist drill. Buy 2 in case of breakage.
Pin vise (hand drill chuck) 1 Home Depot $5.97 Amazon $6.99 Accepts 0–1/8" bits. Not a power drill.
400-grit sandpaper, 1 sheet 1 Home Depot $1.28 Auto parts store $1.50 For prepping aluminum surface
600-grit sandpaper, 1 sheet 1 Home Depot $1.28 Auto parts store $1.50 For deburring the drilled pinhole

Subtotal: $8–$15

3. Chemistry

The Mike Ware New Cyanotype formula — identical to the TBS-001 specification. See Chemistry Shopping List for full formula details and the Pinhole Optics Report for spectral and exposure properties.

Quantities Needed (20 prints + 25% overage)

Chemical Amount needed Min order size Notes
Ammonium iron(III) oxalate / ferric ammonium oxalate (Part A) 30 g 100 g Excess supports 60+ additional prints
Potassium ferricyanide (Part B) 8 g 100 g Excess supports 200+ additional prints
Ammonium dichromate 1 g 10 g Optional — contrast enhancer; omit to save cost

Suppliers and Pricing

Chemical Supplier 1 Price Supplier 2 Price
Ammonium iron(III) oxalate (ferric ammonium oxalate), 100 g Bostick & Sullivan $18.00 Photographers' Formulary $24.50
Potassium ferricyanide, 100 g Bostick & Sullivan $8.50 Photographers' Formulary $9.95
Ammonium dichromate, 10 g Photographers' Formulary $12.00 — —

Supplier URLs:

Chemistry subtotal: $25–$45 (lower end omits ammonium dichromate)

Hazard note: Ammonium dichromate is a Category 1A carcinogen. Wear nitrile gloves when handling. For the PoC, it is safe to omit — prints will have slightly lower contrast but will still produce clear, presentable images.

4. Substrate

Item Qty Supplier 1 Price Supplier 2 Price Notes
Watercolor paper, 10×14" block (20 sheets), hot-press, 140 lb (300 gsm) 1–2 blocks (20–25 sheets) Blick Art Materials (Arches Aquarelle) $44.99/20-sheet block Amazon (Fabriano Artistico) ~$2.50/sheet 100% cotton. Standard 10×14" size — one sheet per print, no cutting.

Why watercolor paper instead of muslin? At the PoC scale (10×14" prints), watercolor paper is the superior substrate: no pre-washing, no stretching, no clipping tension — it lies flat naturally and coats evenly. Muslin is used for TBS-001 only because no paper is manufactured 4.5 meters wide.

Yield: One 20-sheet block = 20 prints, used whole (no cutting). For the 25% practice/waste margin, add a second block or a 10×14" pad. Arches Aquarelle and Fabriano Artistico both ship the 10×14" size in blocks and pads.

Subtotal: $45–$65

5. Tools and Consumables

Item Qty Supplier 1 Price Supplier 2 Price Notes
Foam brushes, 2" (10-pack) 1 pack Home Depot $4.97 Dollar Tree (3-pack) $1.25 Disposable. One per session.
Plastic mixing cups, 8 oz (10-pack) 1 pack Dollar Tree $1.25 Amazon $3.99 For mixing sensitizer
Binder clips, 1" (24-pack) 1 pack Office Depot $2.49 Dollar Tree $1.25 For mounting paper on backing board
Nitrile gloves (box of 50) 1 box Home Depot $7.98 Amazon $6.99 Wear during coating and mixing
Digital kitchen scale (0.1 g) 1 Amazon $9.99 Walmart $8.98 For weighing chemicals. Most kitchens already have one.

Subtotal: $8–$14 (less if you already own a kitchen scale and gloves)

6. Photo Trays

Standard darkroom developing trays — used for both chemistry coating and development washes. The 12×16" size fits inside the 18×18" prep box (external ~13.4×17.5"). The 10×14" paper fits inside the tray interior, lying flat during brush coating.

Item Qty Supplier 1 Price Supplier 2 Price Notes
Paterson 12×16" Developing Tray (PTP326) 3 B&H Photo $10.95 ea Adorama $10.95 ea 1 for coating + 2 for wash. Buy 3 different colors to prevent cross-contamination.

Alternative: Paterson 12×16" Tray Set (PTP336) — set of 3 in white/gray/red, ~$28 at B&H Photo.

Subtotal: $28–$33

7. Light-Seal and Safelight

Item Qty Supplier 1 Price Supplier 2 Price Notes
Red LED bulb (9W, standard base) 1 Home Depot $4.97 Amazon $5.99 Screw into any existing lamp. Cyanotype is not sensitive to red light.
Black cotton fabric (for arm sleeves) 2 pcs — Free Joann Fabrics $3.99/yd Cut sleeves from a black t-shirt (free) or buy 1/2 yard
Rubber bands (heavy duty) 4 — Free Office Depot $1.99 For sealing sleeves at wrists

Subtotal: $4–$7

Budget Summary

Category Low High
Boxes + construction (×2) $11 $16
Pinhole materials $8 $15
Chemistry (without ammonium dichromate) $25 $35
Chemistry (with ammonium dichromate) $37 $45
Substrate (watercolor paper) $45 $65
Tools + consumables $8 $14
Photo trays (Paterson 12×16", ×3) $28 $33
Safelight + light-seal $4 $7
Total (without dichromate) $129 $185
Total (with dichromate) $141 $195

What the Minimum Order Gets You

The chemistry suppliers sell minimum quantities far larger than the PoC requires. The minimum orders provide enough material for:

Chemical Min order PoC needs Remaining for Additional prints
AmFe, 100 g 100 g 30 g 70 g ~45 more
K₃[Fe(CN)₆], 100 g 100 g 8 g 92 g ~230 more
Paper (10×14" blocks, ×2) 40 sheets 25 sheets 15 sheets ~15 more

The leftover chemistry is enough for extended testing, workshops, or demonstrations.

Sourcing Notes

  1. Boxes: You need two identical 18×18×16" corrugated boxes. Buy both from the same supplier for a perfect match. U-Haul, Home Depot, Lowe's, and Staples all carry equivalent sizes. The key specification is the 18" depth (which becomes the focal length).

  2. Drill bit: The 1/32" size is stocked in the drill bit aisle at Home Depot, usually in a small-bits assortment pack. A single bit is ~$4. Buying a set of small bits ($8–12) gives you spares.

  3. Chemistry lead time: Bostick & Sullivan and Photographers' Formulary ship within 1–3 business days to most US addresses. Plan 5–7 days from order to delivery.

  4. Watercolor paper: Must be 100% cotton (rag), hot-press, 140 lb (300 gsm) minimum. Arches Aquarelle is the gold standard for cyanotype — widely available at Blick Art Materials and most art supply stores. No pre-treatment needed (unlike muslin, which requires pre-washing).

  5. Substitutions:

  6. No pin vise? Use a sewing needle pushed through from behind (produces ~0.5mm hole — usable but slower exposure)
  7. No foam brushes? A natural-hair watercolor brush or small paint roller works
  8. No duct tape? Multiple layers of black electrical tape, though less durable
  9. No foam-core board? Stiff cardboard from another box, doubled up
  10. No hot-press paper? Cold-press watercolor paper works but has visible texture in the print