Timer for exposure unit

[hiroh]

I made my standard exposure unit and I have a power switch built-in. I use my phone as a timer and I manually switch on and off the exposure unit. It would be nice to have a small device that can be programmed to turn the power off after certain period, but all I can find on Amazon works in hours only, and I need seconds, because my exposure is 3:30 min. Has anyone found something like this?

 

[albada]

You need a darkroom enlarger timer. Here are some: B&H enlarger darkroom timers

 

[hiroh]

Great, this GraLab looks cool, but it's an expensive for what it does, but I guess I'll give it a try. Thanks!

 

[Rick A]

You can buy used GraLab 300 timers for cheap on EBay. I use one to control my UV exposure unit, they can be set in seconds and minutes up to an hour.

 

[hiroh]

Yeah, they are really cheap on eBay.

How easy is it to set the precise time? Is it clicky, so i can count three clicks for three minutes, or do I have to fiddle with it to get it correct.

For me, the phone is the easiest, because I just press the side button and say "timer 3 1/2 minutes" to Siri and it starts counting down. But then, I really have to pay attention when the time is up to turn off the power, so for that reason I want something automatic, but has to be quite easy to set, like blindfolded

 

[glbeas]

Yes the minute hand clicks and the second hand you just push to the correct time and flip the switch to turn it on.

 

[koraks]

Something like this seems appropriate: https://www.banggood.com/AC110V-220...er-Control-Switch-Relay-Module-p-1747479.html
There's a plethora of similar/identical modules being sold on sites like ebay, banggood and aliexpress. The one above is just one of the first ones that popped up on a 'timer module' search. Give it a try.

Btw, I've used a bare-bones version of that module for years in my UV tube exposure unit. Worked fine.

PS: I recently repaired a couple of Hauck darkroom timers, which are conceptually similar to the Gralab timers. Just my humble opinion, but I find that sort of equipment antiquated, error prone, bulky and ridiculously expensive for what it is. These devices made perfect sense in the 1970s, but today...not so much. If you enjoy your Gralab, Hauck etc., feel free to do so. Not trying to talk you out of it. I just choose differently, to each their own and all that.

 

[Rick A]

There's been GraLab 300 timers in my darkroom since the 1960's. At one time, I decided to sell them all off and replaced them with digital timers, I missed the simplicity of them and bought another. It's like keeping company with an old friend. I kept the digi's for my enlargers, but the 300 operates my UV unit, 95% of my work is done using alt processes these days.

 

[koraks]

It's like keeping company with an old friend

That I understand

 

[jeffreyg]

My GraLab has been in use for 52 years. It has a buzzer if you doze off during a long exposure 🥹. I don’t use it for my enlarger but for developing film and pt/pd printing. However I don’t shut down the light box during a session For the enlarger I use a digital enlarger timer. Just used the GL when developing film a few minutes ago Stayed awake for the 8 minutes so the buzzer wasn’t necessary

 

[Sirius Glass]

I have a digital time that allows me to do minutes and seconds or seconds and tenths of seconds. Check for one that is compatible with your enlarger.

 

[payral]

I connect these timer (cf pdf included) to my UV unit. It works like a charm