Web Apps / Darkroom and Camera Calculators
Recently I have had a great time making simple webpage calculators and applications and hosting them on Github, just click the link and the app will work in any browser! Try them out, I’d love to hear your thoughts!
Large Format Bellows Factor from Subject Distance
While shooting large format, I have always found bellows factor compensation to feel a bit cumbersome in measuring the distance from the film to the lens. I have found it much easier to measure or guess the distance to the subject. Using the calculator, you can input the subject distance and focal length and then the style of compensation you’d like between Aperture, Long Shutter Speed (In Seconds), and my personal favorite, Shutter Speed + Aperture. In this third mode, I have designed the calculator to use the shutter speed to overcompensate, and then calculate to stop down the aperture the fraction needed to make a more granular compensation. For example; a compensation of 1.5 stops is needed, the shutter speed and aperture are 1/125 and f8. The calculator will overcompensate 2 shutter stops to 1/30, and then smartly stop down the aperture the needed 1/2 stop to f9.5.
Even Stepped Grayscale Print Calculator
This one is a little bit silly in how specific it is but nice in it’s lessons on the non-linear nature of darkroom exposures. In my Darkroom 1 class, I make my students make a “Zone System Greyscale Sheet“. This is a sheet of darkroom paper with 11 even steps from pure black to pure white. In order to do this properly with even steps, the exposure times per step need to be estimated logarithmically. This calculator seeks to make that process a whole lot easier. The student needs to find their time to first step of light gray, then their shortest time to pure black. Input that with your desired amount of steps, and the calculator will tell you not only the exposure times per step, but also the proper enlarger timer settings to build up that exposure on the sheet in consecutive smaller exposures. Also, the calculator will generate a sample image of your sheet of paper with the proper amount of steps as the input.
