Photography · From the composite to the finished print
Less mental math.
More time for the image.
Some questions come up again and again when taking photos: How much developer do I need? How does extending the bellows affect the exposure? And how big will a scan actually be when printed on paper? To answer these questions, I've put together twelve handy photography tools here.
The calculators are designed to save you work and make the relationships clear. That’s why you don’t just get a number—you also get the calculation process, an example, and notes on where the model reaches its limits. For me, these things go hand in hand: a practical tool and the ability to not have to trust it blindly.
Chemistry & Temperature
Mixtures & Concentrations
Mix two solutions: Determine the quantities and target concentration using a clear calculation for volume and mass fractions.
Open Calculator ↗Tool 02 / 12Dilute the photochemical solution
Prepare the photochemical solution as a 1+9, 1+25, or 1+50 solution: Calculate the amounts of concentrate and water needed for the desired working solution.
Open Calculator ↗Tool 03 / 12Adjusting the water temperature
Mix cold and hot water to the desired temperature, or calculate the temperature of existing quantities.
Open Calculator ↗Tool 04 / 12Development Time & Temperature
Estimate film development times when the temperature changes, using your own Q10 factor or two validated reference times.
Open Calculator ↗Exposure & Large Format
ND & Reciprocity
Calculate ND filters and reciprocity error together. With film profiles from ILFORD, Kodak, Fuji, and Foma.
Open Calculator ↗Tool 06 / 12Bellows factor
Calculate the exposure extension based on the bellows extension or reproduction ratio, including the time factor and aperture correction.
Open Calculator ↗Tool 07 / 12Print Bellows Ruler
Create a dimensionally accurate bellows ruler for your focal length: third-stop marks, A4 tiles, and a 100-mm reference distance.
Open Calculator ↗Darkroom & Printing
Magnification
Calculate the new magnification based on the image width or the distance between the lens and the paper. A change in aperture can be factored into the calculation.
Open Calculator ↗Tool 09 / 12F-Stop Test Strips
Plan logarithmic test strips using whole or fractional f-stops. Read the total times and additional exposures separately.
Open Calculator ↗Formats & Image Data
Scanning, Pixels, and Printing
Calculate the film format, scan resolution, pixel dimensions, print size, and uncompressed file size all at once.
Open Calculator ↗Tool 11 / 12Film Format & Angle of View
Compare focal lengths and angles of view for different image formats, with separate comparisons for horizontal, vertical, and diagonal perspectives.
Open Calculator ↗Tool 12 / 12Trimming a sheet of film
Calculate a cutting layout for sheet film: Clearly compare the number of sheets, rotation, margins, cutting allowance, and material yield.
Open Calculator ↗For work between the camera and the darkroom
Some of the tools are intentionally very simple: preparing a dilution or mixing two water temperatures. Others help with questions that are a bit more specific—such as a printable bellows scale or a cutting guide for flat film. You can jump right into your question; there’s no need to follow a specific order.
The twelve calculators are part of the same system but remain independent. On each page, you'll find a menu with all the tools and links to further explanations from manufacturers, universities, or other relevant sources. All calculations run in your browser, without requiring you to log in or submit your input.
Especially when working with analog media, testing remains important. Film, developer, paper, and one’s own workflow cannot be fully captured in a formula. Whenever a calculation provides only a starting point, this is explicitly stated. A good test strip and a neatly recorded reference are still irreplaceable.