Curt Palm Photography
CompnTemp: Compensating Developing Timer
Version 2.0 is now available, free, for Mac and Windows.
CompnTemp reads the developer temperature with a USB temperature probe and compares it to your target temperature. When the developer is warmer than the target, the clock runs faster; when it is cooler, the clock runs slower. Development stays the same even when the temperature drifts during a print or a roll of film.
CompnTemp was first released in March 2008. Read a review by Eric Biggerstaff and Alan Ross, published (with photos) in the May/June 2008 issue of View Camera.
Coming soon: an iPhone and iPad version that reads Vernier's wireless Go Direct Temperature probe over Bluetooth is now in testing.
Download
| CompnTemp 2.0 for Mac with Apple Silicon | Macs with an Apple M1 chip or later (48 MB) |
| CompnTemp 2.0 for Mac with Intel | Older Intel Macs (49 MB) |
| CompnTemp 2.0 for Windows | 64-bit Windows 10 and 11 (50 MB) |
| User manual (PDF) | Written for the original version; it still describes the timer, profiles and compensation curves. |
Not sure which Mac you have? Choose Apple menu > About This Mac. If it lists a "Chip" (Apple M1 or later), download the Apple Silicon version; if it lists a "Processor" (Intel), download the Intel version.
Mac: unzip the file and drag CompnTemp to your Applications folder. The app is signed and notarized by Apple.
Windows: unzip the file and run CompnTemp.exe from the CompnTemp folder (keep the files in that
folder together). Windows may show a "Windows protected your PC" warning the first time; choose More info, then Run anyway.
Java is included, so there is nothing else to install.
CompnTemp Is Free
CompnTemp is free to download and use. If you find it useful, please consider making a donation to an organization that teaches photography, such as The Weston Collective, which keeps black and white film photography alive for young photographers through the Weston Scholarship, or to the art or photography program at your local school.
What's New in 2.0
- Runs natively on Apple Silicon Macs and on current versions of macOS and Windows
- No separate Java installation needed
- Safelight display: one menu choice (Configure > Safelight display) turns the whole window deep red, with no green or blue light
- Free, with no license or demo limits
Features
- Toggle between real time and compensated (Comp) time
- Fahrenheit or Celsius
- User settable target temperature
- Count-down or count-up timer modes
- Set the time from the keyboard or the pull-down menus
- Optional USB 10-key keypad for remote start/stop and time entry
- Programmable compensation curve, with three built-in curves: Zone VI film, Zone VI paper and Ilford film
- Savable profiles of your settings; switch between them easily and restore the defaults
- Alert sound in count-down mode at 00:05, and an optional beep at start and stop for working in total darkness
- Multiple print processing in count-down mode
- Metronome beep at an interval you choose
- Single click zero and restart in count-up mode
What You Need
- A Mac or a 64-bit Windows PC
- A Vernier Go!Temp USB temperature probe. Without a probe, CompnTemp still works: set the temperature by hand with the slider.
- A dim, deep red screen. Turn on the Safelight display, turn the screen brightness down, and for extra safety cover the screen with a red filter (rubylith masking film, Lee 026 Bright Red theatrical gel, or red acrylic sheet).
Recommended:
- A USB keypad or footswitch for starting and stopping the timer with wet hands
- A clamp to hold the probe in the tray, such as Alan Ross's Go!Temp clamp, or extra strong water resistant hook-and-loop fastener (3M Marine Reclosable Fastener)
As with any new light source in the darkroom, do your own film and paper fog test with the timer and your computer screen before you develop. Vernier sells its probes for educational use; see Vernier's web site.
See screenshots and photos of CompnTemp in the darkroom. Questions or problems? Email info@curtpalm.com.
CompnTemp does not collect any personal data. See the privacy policy.
