Another UV Light Box (16x20)

[denverjims]

Perhaps some use an external timer to turn it off.

Good point, Randy, as I think I'd be more apt to forget to turn the fan off after I'm done rather than to forget to turn it on when I'm starting to print. But you'd either have to mount a timer switch for the fan circuit instead of a simple on/off one; or add a second plug for the fan power and, as you said, an external timer.

Again, I enjoy KISS-ing more. I'll leave the autopilot stuff to Tesla.
Best, Jim

[sheel]

Looks good to me (although my lawyer would suggest a more cautious response to avoid liability if you blow yourself up, I'll ignore that).

As you noted, miswiring the ballast to the lamps is the biggest risk but the ballasts usually have a wiring diagram for how they are to be used with the lamps. If it is not printed on the top of the ballast, then look the ballast designation up on the web and usually you can find wiring specs. The only other thing, as I noted in my original post, is to choose the correct 'tombstone' for the type of lamp and ballast combination you are using.

Best, Jim

Thanks Jim.

Yeah, I went by the Fulham wiring diagram found here - https://www.fulham.com/WDpdf/wire7.pdf. The ballasts and bulbs work when I went direct to AC. Unfortunately, when hooking everything up (excluding the 2nd circuit with the fans) something in the circuit keeps causing the ballast's internal fuses to blow. I suspect it's either the switch (??) or the wire connectors (e.g. too small, poor connection).

This is the switch I've been trying to use - https://www.homedepot.com/p/Gardner-...W-50/205971618

I changed the wire connectors from WT3 to WT6 which are larger - max 2 #14 gauge wires (WT3) vs. max 4 #12 gauge wire (WT6).

So, I went to Home Depot today and bought these Phillips ballast (4 lamp, instant start, electronic)- https://www.assets.lighting.philips....11a49d00bfc884

I eliminated the switch from the circuit and wired these up directly to AC on the terminal block, with the power plug going to a surge protector - all 3 ballasts and 12 bulbs worked as expected, nothing blown/shorted. Btw, these ballasts don't have an internal fuse, and also I have not yet connected up the fans (e.g. the 2nd circuit).

So, I'm not sure what the heck is going on.

If I wire back in a switch, I'm either going to get an IEC receptacle with fuse-in, or get an in-wire fuse to protect the load size of the switch - probably 5 amp fuse.

[Tin Can]

I don’t like the looks of your original switch.

Looks cheap.

Beware of Trojan Horses.

I would not use an internal switch at all.

External timer switch or use household wall switch in a standard steel electrical box with grounding bolted to the box.

What is the box made of?

Most lamp containers are grounded metal.

Install GFCI in any Darkroom and use it.

[sheel]

Ok, so I've updated my schematic - I'm up and running with the ballasts/lights. I've yet to wire up the fans - will keep you guys posted on the final.

* Using the Phillips REB-4P32-SC ballasts instead of the Fulham WH-5-120L
* I've soldered in a 5 amp fuse on the hot wire coming into this circuit
* Eliminated the switch on the circuit and will use a surge protector to switch on/off

[denverjims]

sheel,
I just used a standard household wall rocker switch for each circuit and had not had any problems with the Fulham's I used. As far as the ballasts were concerned, any brand should be OK once wired properly. The main thing for me was that they were the first ones I came upon which required only 1 ballast to drive 4 bulbs, like the Phillips ones you found.

You changed more than one thing so it's hard to tell what the issue was. Others might be better to judge but I don't believe the 14 vs 12 gauge wire would make a difference. I'd guess that it could have been a bad ballast, or, as Randy said, maybe the switch. At any rate, the important thing was that you are up-and-running. Adding the fan circuit should be no problem given the low additional load. Good job sticking with it.
Best, Jim

[sheel]

sheel,
I just used a standard household wall rocker switch for each circuit and had not had any problems with the Fulham's I used. As far as the ballasts were concerned, any brand should be OK once wired properly. The main thing for me was that they were the first ones I came upon which required only 1 ballast to drive 4 bulbs, like the Phillips ones you found.

You changed more than one thing so it's hard to tell what the issue was. Others might be better to judge but I don't believe the 14 vs 12 gauge wire would make a difference. I'd guess that it could have been a bad ballast, or, as Randy said, maybe the switch. At any rate, the important thing was that you are up-and-running. Adding the fan circuit should be no problem given the low additional load. Good job sticking with it.
Best, Jim

Thanks Jim!

Yeah, many components changed in my scheme. Since about 3-4 ballasts blew at different times, it's highly unlikely to be ballasts.

As for the wiring change - that was specifically the connector, going from a smaller one that is only meant for 2 #14 wires to a larger one that can take 4 #14 wires - I suspect a poor connection.

The switch itself is rated at 16 amps on 125 vac - hard to believe a switch rated for these specs would've caused the issue. As far as I know, a wall switch is not much different than this switch. Not sure how to rule that out w/o blowing fuses, but a moot point now that I've got a scheme up and running.

Very thankful for this thread and others that have helped me! I'll be writing up a blog post too on this schematic once I'm done.

[drewf64]

Hello Jim:
I have been reading through your UV light box posts with great interest ... great build and information share!
I have been making albumen prints recently using a natural light mixture of direct sun & clear blue northern sky.
Everything goes well when the light is perfect. However, I have only had two printing sessions with great light allowing for 6-12 minute exposures.
So ... a couple of questions:
* You referenced salt printing in one of your posts ... have you printed on albumen?
* What have the exposure range lengths been with your box?
* Would the UV output be any different between classic salt and albumen?
THANK YOU!!
Drew

[Robert Brazile]

Can't speak for Jim, but I've done a fair bit of salt and albumen printing with mine. 20 minutes is not unusual (mine was based on one of Jim's designs, has a bank of 12 fluorescent BLBs) but of course it depends on the negative and the particular sensitization formula you use. It's the usual story: print until it looks good, then print a bit longer. If the border starts solarizing/turning metallic looking, you're pretty much there.

Exposures should be roughly the same for salt vs. albumen; after all, it's basically the same process, just with some underlayment in one case, so to speak.

Robert

[denverjims]

... a couple of questions:
* [1] You referenced salt printing in one of your posts ... have you printed on albumen?
* [2] What have the exposure range lengths been with your box?
* [3] Would the UV output be any different between classic salt and albumen?

Hi Drew, Sorry for the delay but was 'out of the evil influence of the internet' last week.

In answer to your questions:

1. 'No' on Albumen, but from what I've read, I believe that Robert is correct and Salt and Albumen times could be similar.

2. Anywhere from 15-25 minutes, varying on the look I've been trying for and the negative density I was using. I shoot 4x5 film negatives, scan, then process with Photoshop. Finally print out using transparency material. Correct on having edge begin to turn to indicate when it's near done. But like in enlarging times, a lot of your exposure times will depend on the look (density) you are trying for and the density of your negative you are trying to print through. Also varies with the silver concentration of your paper coating (for more on this - which might pertain to Albumen as well - see Ellie Young's publications on the Salt printing process - she has a published book and her thesis for her RMIT graduate work as well.)

3. Not sure what you mean here. The UV output is what it is. It is independent of what is underneath. If you meant to ask if the effect on Albumen prints is different than Salt, then I'd guess not a lot. But others who have done both would be better suited to answer that question (as in #1).

Hope that helps and glad that this thread has been useful. As I said in the beginning, I used a lot of ideas I had found in some previous builds, so just trying to pay-it-forward some.
Best, Jim

[drewf64]

Hi Drew, Sorry for the delay but was 'out of the evil influence of the internet' last week.

In answer to your questions:

1. 'No' on Albumen, but from what I've read, I believe that Robert is correct and Salt and Albumen times could be similar.

2. Anywhere from 15-25 minutes, varying on the look I've been trying for and the negative density I was using. I shoot 4x5 film negatives, scan, then process with Photoshop. Finally print out using transparency material. Correct on having edge begin to turn to indicate when it's near done. But like in enlarging times, a lot of your exposure times will depend on the look (density) you are trying for and the density of your negative you are trying to print through. Also varies with the silver concentration of your paper coating (for more on this - which might pertain to Albumen as well - see Ellie Young's publications on the Salt printing process - she has a published book and her thesis for her RMIT graduate work as well.)

3. Not sure what you mean here. The UV output is what it is. It is independent of what is underneath. If you meant to ask if the effect on Albumen prints is different than Salt, then I'd guess not a lot. But others who have done both would be better suited to answer that question (as in #1).

Hope that helps and glad that this thread has been useful. As I said in the beginning, I used a lot of ideas I had found in some previous builds, so just trying to pay-it-forward some.
Best, Jim

Hello Jim:

Off the grid last week? Nice place to be !!
Thank you for your reply ... greatly appreciated!

In my question about exposure ranges ( I should have said times ) I was just looking for a comparison between time using the Sun vs. the light box ...
eg. The box times are 1.5x times as long, 2x the time, etc.

Re: Your comment to my question #3 =
I should have been more clear.
What I was trying to ask was ...
Is the "best" UVA wavelength different for Salt vs Albumen?
Because I need to choose BL vs. BLB tubes.
USHIO offers BL @ 352nm and BL & BLB @ 368nm.
A 16nm differential is splitting hairs and perhaps inconsequential.
But since I need to choose ... would one be better for Albumen vs. the other?
Again ... thank you.
Drew