I grew up with two photographer parents that built a house around photographic printing. I was looking through their exposure notes a bit ago and as long as you can get sub second you should be able to get some pretty consistent results.
They did color, so when printing there was no such thing as a safelite. I can still vividly remember being that "can I help?" age and setting the timers for each color, loading in the paper in complete darkness, firing up the enlarger, and then feeding it to the auto processor. It was certainly an interesting way to grow up.
So cool. Black and white printing is a different beast, where you can get away with much less precision and you can produce fantastic results by just eyeing things and winging it. I know a printer who operates like this, gauging the developement by a pair of well trained eyes, and know others who treat their darkroom as a scientific laboratory and do density tests and swear by their DIY chemistry etc.
Lot's of ways to do it, in the end, if you enjoy the process, then all is good.
Very cool. Is it controlling the plugs via direct Bluetooth connection? Or zigbee via a hub, or wifi (direct or via service)?
I always assumed, probably incorrectly, that there would be too much jitter in the actual timing so I had built a few prototypes of e.g. an esp8266 controlled relay, where you would give the MCU a duration rather than separate on/off commands. But I guess that was wildly over-optimizing. In your case, how stable is the delay from the app sending a command until the switch operates?
I'd add voice mode for color printing in total darkness.
Voice mode… interesting. Not sure about that. Handsfree operation is traditionally done with foot switches in the darkroom. You mean like “hey Siri, expose for 8 seconds”?
> Set up your smart plug and note its local IP address. Make sure the plug and your iPhone or iPad share the same local network. Connect your enlarger to the smart plug. Enter the plug’s local IP address in Darkplug, and connect. Once set up, you can control the enlarger directly from your iPhone or iPad.
I was curious about timing accuracy too, has any testing been done on this? Is it accurate to 1s, 0.1s, 0.01s? How dependent is it on the smart switch hardware?
Using slow motion recording, I measured 0.1s accuracy. I'd say it's more than good enough. You can see a print on the website I made with the app and a smart plug. The average print needs between 4-60s of exposure.
As for how dependent it is on that specific type of hardware (Shelly plugs), it is 100% dependent as the app directly controls the smart plug (with the help of the router ofc). There is no way around it, no other smart switch family is currently supported.
I'd probably put the typical smart switch hardware/software stack at around 0.25 seconds. Maybe you can but I don't think I'd try to rely on anything much faster than that.
If you did, I would go in the custom firmware for the smart switch direction. A lot of them are just an ESP32 inside, and you could probably get to 0.001 seconds that way (but you are switching AC which cycles on the order of 0.02 seconds, so whatever)
If I were to tackle this project, I’d use an ESP32 and a relay with 120V contacts. That way you can use a GFCI receptacle and be code compliant if your darkroom is in a basement or the enlarger receptacle is near your darkroom sink.
Many such projects were actually made, some of them are better documented then others. For this application I wanted something that is as off the shelf as possible.
I get that red-on-black color scheme is a nod to the red lighting of a dark room, but the contrast is so low I can hardly read the example screenshots.
It’s not a nod. It’s required to not ruin the paper during use. A specific yellow would also work but phone screens often output more than just the desired color. Red is the safest.
Isn't it more than a nod, and actually a hard requirement to be considered for use in an active darkroom?
It hadn't occurred to me that now with OLEDs you can actually safely limit exposure to wavelengths that would be damaging to the development process - I'd imagine that is what the author is shooting for here
I upgraded to an Apple Watch Ultra because it offered a face with only red and black. It’s been long enough now that I don’t remember all the details, but I appreciated being able to monitor time in the darkroom (using DND to avoid flashes of light).
Fun fact, I planned an Apple Watch companion app as well, but the Apple Watch is just too erratic in the way it lights up randomly, no matter what app (live activity?) you run, and there is no way to put a red filter on either.
Trust me, in the dark, your eyes adapt and you will be able to read the GUI just fine. And as someone said, the reason the GUI is like this, is to not emit unnecessary light in the darkroom, thus preventing fogging the paper.
25 years ago my dad built me a darkroom timer with a relay and a PIC 16F84A. It only had one button that you used a combination of short and long presses to adjust the time (read on a 7 segment LED display) and trigger the exposure.
I recently took a B&W film development and printing class and it was very cool. I wouldn't be inclined to do it again, but it was fun to understand what 'dodging' and 'burning' refers too and get your hands do something.
They did color, so when printing there was no such thing as a safelite. I can still vividly remember being that "can I help?" age and setting the timers for each color, loading in the paper in complete darkness, firing up the enlarger, and then feeding it to the auto processor. It was certainly an interesting way to grow up.
Lot's of ways to do it, in the end, if you enjoy the process, then all is good.
I always assumed, probably incorrectly, that there would be too much jitter in the actual timing so I had built a few prototypes of e.g. an esp8266 controlled relay, where you would give the MCU a duration rather than separate on/off commands. But I guess that was wildly over-optimizing. In your case, how stable is the delay from the app sending a command until the switch operates?
I'd add voice mode for color printing in total darkness.
> Set up your smart plug and note its local IP address. Make sure the plug and your iPhone or iPad share the same local network. Connect your enlarger to the smart plug. Enter the plug’s local IP address in Darkplug, and connect. Once set up, you can control the enlarger directly from your iPhone or iPad.
I think you can work around it very easily by stopping down the lens and using filters.
But I’m sure if the phone has direct connection to the device and not working through hubs it’s not anywhere near 1s of delay.
As for how dependent it is on that specific type of hardware (Shelly plugs), it is 100% dependent as the app directly controls the smart plug (with the help of the router ofc). There is no way around it, no other smart switch family is currently supported.
Note also that some of the best printers used metronomes to count exposure time and turn the enlarger light on and off manually.
If you did, I would go in the custom firmware for the smart switch direction. A lot of them are just an ESP32 inside, and you could probably get to 0.001 seconds that way (but you are switching AC which cycles on the order of 0.02 seconds, so whatever)
It hadn't occurred to me that now with OLEDs you can actually safely limit exposure to wavelengths that would be damaging to the development process - I'd imagine that is what the author is shooting for here
Shellys can be configured to connect to your wifi and are not dependent on any cloud service.