Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Darkroom timers, and then there was FADU

  1. #1

    Join Date
    Feb 2021
    Location
    Alberta
    Posts
    6

    Darkroom timers, and then there was FADU

    My first enlarger timer was a Gralab--you know, the one with the minute and second hands. The last second on it isn't very accurate.

    Then I got ahold of a Gralab 505 electronic timer, with buttons and switches. It worked OK, but I had to avoid using a couple of the switches because they were dirty and weren't reliable. It was also a little quirky to use. These are both standard/linear timers.

    Then I heard about the FADU f/stop timer app. I've heard about working with an f/stop timer, which calculates test strips and adjusts single exposures using f/stop increments instead of linear timing. Where it shines is doing test strips. I used to do them a fixed number of seconds apart, for example, 5, 10, 15, 20, 25 seconds, but the lower numbers are a one stop jump and they get smaller as you go up. The app alone can calculate the timing for different increments of f/stops, which is helpful in itself if you set your timer manually, but I was curious about getting the smartphone to control a wifi relay as per the description in the app store.

    I had an old smartphone with an OLED display (apparently better than a backlit display because it puts out pure red, with no green backlighting bleeding through), so decided to try putting together a wifi relay for it. $15 worth of parts later (1 LC tech wifi relay board, 1 5v power supply, 1 electrical outlet, 1 outlet cover, 1 switch, 1 outlet box) and a bit of soldering and I got a pretty sweet f/stop timer setup. I turned down the display on my smartphone to minimum, uninstalled any extraneous apps, turned off all notifications, and tested the red display of the app by putting it upside down against a piece of photographic paper for 30 seconds, with no exposure of the paper, so the OLED display works great displaying a red that the paper is insensitive to.

    The wifi relay even has a normally closed switch so I connected that to the safe light outlet, and the enlarger connects to the normally open part of the relay. The timer is interesting. I normally do test strips 1/3 stop apart, but if I need a rough idea, I can set it to 1 stop apart. It seems to be able to time split seconds, so I've taken to shorter exposures since the timer will do it accurately. You can compensate for any latency in the wifi signal/relay if you want, but I haven't found the need. I've included a pic of the setup below (the smartphone display is brightened for dramatic effect).

    Click image for larger version. 

Name:	IMG_0412.jpg 
Views:	107 
Size:	59.1 KB 
ID:	213137

    I'm pretty happy with the setup because: It only cost $15 (and makes use of an old smartphone), it's small, and it gives me f/stop timing capability. I can provide more details on assembly if requested.

  2. #2

    Join Date
    Jun 2014
    Posts
    1,784

    Re: Darkroom timers, and then there was FADU

    That's very nice! I'm particularly impressed by the OLED paper fog test, which I would have never expected to come out so well.
    The way you've set this up almost eliminates my hesitations about using a smartphone as a HID in a darkroom setting. I do quite like the screen layout of that app. I'm sure it's pretty convenient to use.

  3. #3

    Join Date
    Sep 2010
    Posts
    640

    Re: Darkroom timers, and then there was FADU

    One of the challenges in making a good print is determining the correct exposure. The accuracy of the timer is important, as are a visible way to monitor the timing cycle and certainly an audible metronome tone on the timer. Of greater concern, is the startup characteristics of the particular light source. Fred Picker tried to address this in with several electronic devices.

    The step wedge has been around for ages in the graphic arts and commercial photography industries. The Kodak (and others) Projection Print Scale was in regular use in amateur, student, military and commercial darkrooms. Because the scale was exposed for 30 seconds or one minute, the startup characteristics for the lamp are compensated for on the scale. With cold light tubes, the tube must be at a warm and stable operating temperature. A ten second burst from an cold tube could be as much as a stop and a half from that of a warm and stable tube. Even halogen bulbs have a lagging start up. A three second burst from a halogen light does not provide the same exposure as three seconds of a thirty second exposure.

    I use both a Kodak Projection Print Scale (or similar) and exposure meters, on the easel and recently on the Beseler cold light head itself. When I make a test strip across a print, or section of a print, I use an audible timer with a foot switch. I make a 30 sec test strip by covering the paper completely at the start of the 30 sec timer. I uncover a new strip every three seconds. This test takes bulb characteristics into consideration. Perhaps contrast as well, because brief bursts of halogen tend to be yellow.

  4. #4
    Tin Can's Avatar
    Join Date
    Dec 2011
    Posts
    16,073

    Re: Darkroom timers, and then there was FADU

    some enlargers had shutters to better time stable lamp light
    2022

  5. #5

    Join Date
    Feb 2021
    Location
    Alberta
    Posts
    6

    Re: Darkroom timers, and then there was FADU

    Hmmm... good points--I just have an old school incandescent 15 watt bulb in my enlarger which I'll test using a suggested method in the FADU documentation (do 10 - 2 second exposures and compare that to one 20 second exposure), then play around with the bulb delay if they're different. It'll also do series of single test strips with accumulative times for more accuracy if the bulb is an issue. I imagine if the bulb has both spectral and illuminosity issues under a specified energized time frame, either individual exposures would have to exceed that time by an amount which brings accuracy into an acceptable margin of error, or switching to using a series of single test strips would help. I'm thinking of trying the single series test strip method since I would be able to compare the same part of the negative with the different exposures.

    Also, this app can be used in a manual switch mode, so that it beeps either all the time, or a 5 second countdown to the end, or just emits a small beep 1/2 second before, then another larger beep to either switch off, or move the card.

    And, if back lighting is an issue, they suggest a rubylith screen might help.

    Quote Originally Posted by Neal Chaves View Post
    One of the challenges in making a good print is determining the correct exposure. The accuracy of the timer is important, as are a visible way to monitor the timing cycle and certainly an audible metronome tone on the timer. Of greater concern, is the startup characteristics of the particular light source. Fred Picker tried to address this in with several electronic devices.

    The step wedge has been around for ages in the graphic arts and commercial photography industries. The Kodak (and others) Projection Print Scale was in regular use in amateur, student, military and commercial darkrooms. Because the scale was exposed for 30 seconds or one minute, the startup characteristics for the lamp are compensated for on the scale. With cold light tubes, the tube must be at a warm and stable operating temperature. A ten second burst from an cold tube could be as much as a stop and a half from that of a warm and stable tube. Even halogen bulbs have a lagging start up. A three second burst from a halogen light does not provide the same exposure as three seconds of a thirty second exposure.

    I use both a Kodak Projection Print Scale (or similar) and exposure meters, on the easel and recently on the Beseler cold light head itself. When I make a test strip across a print, or section of a print, I use an audible timer with a foot switch. I make a 30 sec test strip by covering the paper completely at the start of the 30 sec timer. I uncover a new strip every three seconds. This test takes bulb characteristics into consideration. Perhaps contrast as well, because brief bursts of halogen tend to be yellow.

  6. #6
    Nicholas O. Lindan
    Join Date
    May 2006
    Location
    Cleveland, Ohio
    Posts
    248

    Re: Darkroom timers, and then there was FADU

    To find the lamp's turn-on & turn-off compensation:

    http://www.darkroomautomation.com/su...2LampDelay.pdf

    Nicholas Lindan
    Darkroom Automation

  7. #7

    Join Date
    Dec 2014
    Location
    Beuningen (GLD)
    Posts
    30

    Re: Darkroom timers, and then there was FADU

    I’m into this timer also.
    Did try to build a f-Stop timer with arduino projects that are several to find on the internet, but the disadvantage to my point of view is that these get to much fancy options and result in a user interface in which you easy loose your way.

    Ordered a Sonof basic r3 which I hope to receive in a few days and go to give it a try.
    Looks on the app user friendly.
    Thanks Nicholas about the explanation of lamp delay.
    Best regards

    Hans

  8. #8

    Join Date
    Dec 2014
    Location
    Beuningen (GLD)
    Posts
    30

    Re: Darkroom timers, and then there was FADU

    I received the Sonoff a few days ago and yesterday spend some time to get it connected to the app.
    I just finished the power switch because the Sonoff I did buy only has one on switch. This now controls a second relay which switches between the enlarger lamp and safety lamp.
    Very user friendly interface, no hidden menus, very straight forward.
    If in doubt you can simply download the app on your phone or tablet and figure out how easy it works. The app is for free.
    Only downside, it is not (yet) available for IOS.
    Because I want to avoid too get a phone call in the middle of a printing session I found a used but still working android Tablet.
    That one will be darkroom dedicated and I can leave the phone out :-)
    The only costs is a Sonoff device of less than 10 euro here in Europe.
    Best regards

    Hans

  9. #9

    Join Date
    Feb 2021
    Location
    Alberta
    Posts
    6

    Re: Darkroom timers, and then there was FADU

    How did reprogramming the Sonoff go? I understand you need some sort of USB adapter to do it. And, I'm curious how what kind of tablet you have and how it did in the fog test on paper. I think a dedicated android device is a good idea because of the phone call or other notification issue. And, I do think getting the Sonoff is a better idea if you have a higher wattage enlarger since it has a higher amperage relay than the LC tech board. And, do you have a pic of your final setup?

    Quote Originally Posted by Kodak View Post
    I received the Sonoff a few days ago and yesterday spend some time to get it connected to the app.
    I just finished the power switch because the Sonoff I did buy only has one on switch. This now controls a second relay which switches between the enlarger lamp and safety lamp.
    Very user friendly interface, no hidden menus, very straight forward.
    If in doubt you can simply download the app on your phone or tablet and figure out how easy it works. The app is for free.
    Only downside, it is not (yet) available for IOS.
    Because I want to avoid too get a phone call in the middle of a printing session I found a used but still working android Tablet.
    That one will be darkroom dedicated and I can leave the phone out :-)
    The only costs is a Sonoff device of less than 10 euro here in Europe.

  10. #10

    Join Date
    Dec 2014
    Location
    Beuningen (GLD)
    Posts
    30

    Re: Darkroom timers, and then there was FADU

    I did not reprogram the Sonoff, just put it in DIY mode and added it to my Wi-Fi network with the procedure in the PDF.
    For programming my Sonoff R3 you don't need a USB connection but can reprogram it over Wi-Fi.
    Also in this device there is no connector for this USB device, just the holes in the PDB.
    For now I first will see if it causes delays without reprogramming otherwise of course I will follow that path.

    Here a pic of the tablet with my enlarger. The Sonoff is not visible on the picture.

    Click image for larger version. 

Name:	20210312_095525 (1).jpg 
Views:	18 
Size:	28.6 KB 
ID:	213705

    Strange the picture is upside down. Also when rotated 180 degrees it still stays upside down.
    Last edited by Kodak; 15-Mar-2021 at 04:01.
    Best regards

    Hans

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •