Educational tools and personal records

Choose the question you are trying to answer. Calculators expose their units and assumptions; qualitative models never generate a validated formulation. Personal records stay in this browser and can be exported. Each page includes a useful written method when JavaScript is unavailable.

• Dilution and concentration — Calculate stock volumes, distinguish 1 + n from 1 in n, and relate mass, final volume and molar mass.
• Pinhole and exposure — Work from a measured hole and film distance; keep the optical exposure separate from a material-specific reciprocity correction.
• Chemistry selector — Choose a photographic intention and examine the chemistry class, its limitations and the supporting course evidence.
• Formula designer — Explore sourced directions of change without inventing a recipe, mixing quantity or performance prediction.
• Sensitometry workbench — Import measured density data, choose a fitting interval, inspect a curve and export its readings.
• Tone-reproduction laboratory — Explore how subject range, flare, negative slope and paper range combine in an explicitly simplified model.
• Consumables calculator — Scale a documented session or enter your own quantities; see priced consumption separately from missing prices.
• Student inventory — Keep equipment and chemical stock records in this browser and export a portable backup.
• Laboratory notebook and formula versions — Record the hypothesis before the run, the actual processing conditions, and the result and next change afterwards.
• Exposure log — Keep exposure predictions, measured camera geometry, processing and the finished-image assessment together.