PanterLA

PanterLA is NordicLab’s open-source film-processor development project. These engineering logs follow thermal prototypes and the rebuild of existing rotary machines. Measurements, component identification, and proposed designs are kept distinct; a water test is a development result, not a completed photographic-process qualification.

Follow the current work through:

Heating methods — the original jacket, air, and waterbath comparison.
Direct heating — a compact, actively mixed reservoir and the alternative dip-and-dunk concept.
THD Lift inspection and warm-up — the failed drive and measured bottle lag.
THD Lift stability and teardown — corrected probe readings, opened hardware, and remaining verification work.
JOBO CPE2 temperature and transfer — a second processor and the receiving-drum temperature trace.
Drum-drive motor selection — the simplest practical drive to test first.

The temperature experiment bundle provides the reviewed THD Lift and JOBO CSVs, saved summaries, and an independent verifier. The 1 October 2026 review reproduced 189 numerical metrics across 6,348 observations; it does not establish sensor calibration or certify a finished machine.

Choosing PanterLA's Drum Drive: Stepper or Servo?

For PanterLA’s loaded drum, the first prototype is a NEMA 17 stepper with the existing TMC2209, a direct connection, and independent drum-motion sensing. Here’s why a servo isn’t automatically quieter, why torque headlines can’t be compared, and what the loaded test needs to decide.

JOBO CPE2 transfer test showing source-bottle readings and the receiving drum rising to 38.94°C then cooling

JOBO CPE2: Warm Bottles, Uneven Readings, and a Cooling Drum

The JOBO CPE2 produced locally steady readings, but different locations did not converge. The transfer test adds the process question: warm liquid entered the rotating drum, then its measured temperature fell. What this means for preheat, circulation, and Panterla’s readiness criteria.

Hand holding the THD Darkroom CP Lift's removed control module, wires and connectors visible, next to the open bath enclosure

THD Lift: Bath Stability, Bottle Lag, and the Opened Machine

The corrected bath-corner readings were locally steady, but the bottle was still warming. The teardown also exposed wet-area wiring problems and identified the installed controller as WH1435A. Small temperature variation does not establish accuracy or electrical safety.

THD Darkroom CP Lift processor on a workbench, showing the control box, water bath, and three processing bottles inside the tank

A Broken THD Lift as a Real-World Test Subject for PanterLA

The pump, heater, and Willhi WH1435A controller operated, but the exposed gear drive failed. Follow-up logging put numbers on the thermal lag: the three-corner mean reached 38°C at 24.3 minutes; the bottle was still below it at 39.3 minutes.

Direct heating rate test — linear fit of 24V immersion heater bringing 500ml of water from room temperature to 38°C

Direct Heating Film Chemistry: Why Panterla Is Moving Beyond the Water Bath

A note on the name. “Panterla One” is the working name for this automatic film developing machine — nothing is finalized yet, but it’s the name used for the project going forward in these engineering logs. Summary. I tested direct heating as a replacement for the traditional water bath in the Panterla automatic film development machine. The prototype used a 24 V / 150 W immersion heater, approximately 500 ml of water, active circulation, a digital temperature probe, and closed-loop temperature control. The measured linear heating rate was 3.59°C/min, corresponding to an extrapolated 20→38°C heat-up time of 5.02 minutes. During a separate steady-state test, the recorded temperature had a standard deviation of only 0.033°C over the analyzed four-minute window. The experiment also exposed a separate problem: the control probe and external logger disagreed by about 0.3°C, showing why stability and absolute accuracy must be treated as two different engineering problems. ...

Chemicals heating module for automatic film developer — 3D model with fan

Heating Methods for C-41: Which One Wins?

Precise temperature control is one of the hardest engineering problems in an automatic film developing machine. This experiment used 38°C as its reference, but the working temperature and tolerance must come from the selected chemistry’s instructions. For an autonomous machine, I needed to compare how quickly each heating approach brought the liquid toward that reference and how much its recorded temperature varied afterward. I compared five heating approaches in six configurations, including runs with and without active stirring. These are the original results; the later processor experiments linked below add process-container and transfer measurements rather than replacing this dataset. ...