Question on Ballasts

[Patrick Kolb]

In building a UV lightbox using F20T12 BL tubes, I was looking at two different ballasts. The first is a RL2SP20 TP, which has a ballast factor of .61 and the other is a HM2SP20 TB, which has a ballast factor of .85. With limited knowledge, it seems that the higher the ballast factors the more light output.
So my question, is there much difference in printing time using one or the other, this is for platinum/palladium printing. There have been some excellent discussions about the tubes, but I couldn’t find much on ballast. Any help would be appreciated.

 

[Peter De Smidt]

Ballasts come in two types, 'electronic' and 'magnetic'. The 'magnetic' ones are cheaper. The 'electronic' are better. The are more efficient and have less flicker. You can get them for approximately $20 at a home improvement store. I don't know about the ballasts you mention, but the more efficient one sounds like an electronic one. If so, I'd get that one. Btw., both types are electronic, as in they use electricity. For some reason, though, that designation is still used to name a type of ballast.

 

[Patrick Kolb]

Thanks Peter, I agree that it is important to get electronic ballast. I think both of these are, but I seem to remember someone saying that not all ballasts are equal, and I was hoping to have someone explain the difference and how it relates to the time of exposure.

 

[sanking]

Thanks Peter, I agree that it is important to get electronic ballast. I think both of these are, but I seem to remember someone saying that not all ballasts are equal, and I was hoping to have someone explain the difference and how it relates to the time of exposure.

The ballast factor is defined as the lumens a particular lamp will produce when operated by a specific ballast. It is a percentage of th total lumens possible. A ballast with a ballast factor of 95 percent should produce about 95 percent of a compatible lamp's rated lumens. For example, if a specific tube is rated at 3000 it will produce 2850 lumens with a ballast that has a factor of 95. So, yes, if two ballasts are compatible with a given tube the one with the higher ballast factor will produce the most lumens. And more lumens should result in faster printing times.

Please note that the ballast must be correctly sized for the tubes and using the wrong size ballast may result in excessive current flow, with overheating. I am not familiar with the specific ballast you mention but someone at the store should be able to tell you which ballast is compatible with which tubes.

Sandy King

 

[Patrick Kolb]

Thank you Sandy. It seems that as the ballast factor increases so does the price. Is there a point of diminishing return, where the increase in the factor does not effect the printing times that much?

Also, anyone have any suggestions as to what ballast to use with the tubes mentioned?

 

[climbabout]

Thanks Peter, I agree that it is important to get electronic ballast. I think both of these are, but I seem to remember someone saying that not all ballasts are equal, and I was hoping to have someone explain the difference and how it relates to the time of exposure.

Patrick - I have worked for my family's electrical supply business for over 30 years and I am familiar with the 2 ballasts you are interested in. Those 2 catalog numbers you mention are made by a company called Advance. We are a distributor for both Advance as well as a company called Universal. Those ballasts you mention are both magnetic and are designed to operate 2 F20T12 lamps. Neither company lists an electronic ballast for that lamp configuration. I'm sure it has to do with the fact that the 2 foot T12 lamp is no longer widely used except for specialty applications. Sandy King's explanation about ballast factor and light output is right on the money. Regarding cost - the RL series is worth about 35.00 and the HM series about 45.00. In theory, the light output difference is approx 30%, so you need to decide if the cost difference is worth it. Be aware however, that real life measurements do not always exactly coincide with the specs the manufacturer lists. Please also be aware that the case size on the RL series is 6-1/2" and the HM series is 9-1/2". One other difference is that the HM series is designed to operate down to 10 deg. F and the RL series is designed to 50 deg. F. - this is probably of no consequence for your application.
Climbabout
Tim Jones

 

[Michael Mutmansky]

Patrick,

Most electronic ballasts have higher ballast factor values than both of these (although the .85 BF is near the range and could be electronic). If there is a substantial difference in price, my guess is the difference is due to one being electronic.

We are making an assumption (which is pretty solid) that the UV output increases in the same manner as visible light output. With that regard, the higher the BF, the 'faster' the lamps will be.

If you can provide more information on the ballasts, I can see what information I have in my literature.

---Michael

 

[Michael Mutmansky]

I just saw Tim's post. The difference in price is due to the low temperature rating...

I figured neither of these are electronic, because the BF is too low for a typical electronic ballast.

You may not have a lot of choices for electronic ballasts, but I think there may be one or two that are designed for 48" lamps that will also drive the 24" lamps. Actually, they will be over-driven, increasing the BF a bit to speed up the printing.

Let me see what I can find.


---Michael

 

[Patrick Kolb]

Thank you Tim and Michael, this is just the information I was hoping to get. I look forward to any suggestions you may have.

 

[Michael Mutmansky]

Patrick,

Boy, looking over my literature here, it sure does seem like there are almost no ballast options left in the T12 lamps. The technology has moved on, and the T12 lamps that are left are all specialty lamps in one way or another. I suspect it is not a large enough market to make a good electronic ballast for them.

I've got a call in about multipurpose ballasts. Some can be used for multiple lamp combinations, but the literature may not be entirely complete on the various compatibilities that they have.


---Michael

 

[Michael Mutmansky]

Patrick,

You're out of luck on the electronic ballasts. Those lamps require a starter, and the lamp technology falls into the 'preheat' category.

While they may work on an electronic ballast, they are not recommended by the manufacturer to be used that way. Your best option is to find someone who has made an exposure unit and see if any of them have successfully used electronic ballasts. I can't speak from personal experience either way.

If you were using 4' lamps, this would be an easy issue to solve, but the shorter lamps are a bit of a problem.


---Michael

 

[PaulH]

It looks like the aquarium people are into this as well. You might want to take a look at this:

http://www.plantedtank.net/articles/Overdriven-Normal-Output-ODNO/18/

If you are interested you can find out more stuff by searching for ODNO in Google.

One of these days I am going to give this a try.

Paul

 

[sanking]

Patrick,

Boy, looking over my literature here, it sure does seem like there are almost no ballast options left in the T12 lamps. The technology has moved on, and the T12 lamps that are left are all specialty lamps in one way or another. I suspect it is not a large enough market to make a good electronic ballast for them.


---Michael

Patrick, in case you (or someone else) is interested I have three UltraLux Combination Ballast units for sale that may work for you. They are Instant Start Electronic Ballast for use with 1, 2, 3 or 4 tubes, including T5, T8, T10 and T12 style lamps. Each of these ballasts would run up to four F20 T12 bulbs or four F40 T12 bulbs. I just checked with www. fullspectrumsolutions.com to make sure about this.

I bought these units several years ago to upgrade my 12 tube F40 T12UV unit but never got around to doing it, and now that I have the Amergraph ULF-28 unit I have decided not to do the upgrade. These ballasts have never been used, in fact, are still in their original shipping box. I will sell all three for $70 plus shipping, which is a lot less than I paid for them. They were advertised for high power factor, though I don't find the specifics on the unit itself.

Anyway, I am fairly certain that this is a pretty good deal since original price was about $50 per unit.

UltraLux ballast are sold through www. fullspectrumsolutions.com, but these units are several years old and no longer on their web site.

Sandy King

 

[Patrick Kolb]

Paul, thanks for the link. Their link to BallastWise has a lot of options.
Sandy, I'm out of town for a few days, I will get back to you soon.
What would people recommend for a 24 inch uv light source. I just don't have the room for a larger unit.
Again thank you everyone that has responded.

 

[Ray Bidegain]

Patrick:

I have a box with 12 of the 24 inch tubes and 6 of the RL2SP20 TP ballasts. It all works fine but if I could increase output with a different ballast I would be very interested to hear about it. Many of my printing times with negatives developed in a pyro formula are in the 30-60 minute range and shorter times would be very welcome.

Ray Bidegain

 

[sanking]

Paul, thanks for the link. Their link to BallastWise has a lot of options.
Sandy, I'm out of town for a few days, I will get back to you soon.
What would people recommend for a 24 inch uv light source. I just don't have the room for a larger unit.
Again thank you everyone that has responded.

With 24" tubes I would recommend about twelve tubes spaced 1-1.5" apart. This spacing allows placing the printing frame at about four inches from the bulbs, which will eliminate any possibility of uneven distribution of the light. The best tube overall in my opinion is the BL, and there is no difference so far as i can tell between Sylvania, GE and Phillips. The BL tube works equally well for dichromated colloid processes and iron processes, which covers most of what we do. If you are only interested in printing with the iron processes the SA tube is a good tube, but not better than the BL IMO. Some people claim it is faster, but I tested the two types in the same printing unit and in every test the BL printed as fast or faster than the SA.

Some people have also reported faster printing times using HO (high output and VHO (very high output) tubes and ballast. For example, normal 24" tubes are 20 watts, HO tubes are 40 watts and VHO tubes are 75 watts. Again, I compared printing speed with regulr tubes and ballast and VHO tubes and ballast and while there was some gain in printing speed the considerable extra expense is hard to justify.

I strongly recommend electronic ballast over magnetic ballast. The gain in output can cut printing times by 1/4 to 1/2 of a stop.

Sandy

 

[cperez]

Folks,

What kind of print times are people getting with non-pyro negs using the kinds of light boxes being discussed here?

... Many of my printing times with negatives developed in a pyro formula are in the 30-60 minute range and shorter times would be very welcome...

 

[sanking]

Folks,

What kind of print times are people getting with non-pyro negs using the kinds of light boxes being discussed here?

With kallitype and palladium my print time with a Stouffer step wedge negative is about two minutes with a bank of BL tubes, about one minute with the AmerGraph ULF-28. Exposures for digital negatives on Pictorico are about 1/4 more.

On the other hand I have some over-exposed negatives that take as much as 1-2 hours to print. Printing times are determined by shadow density, and a well-exposed negative, whether developed in a Pyro staining developer or a non-staining developer, will have about the same printing time. Unfortunatley, many people over-expose their negatives, adn over-exposure can result in a huge increase in printing times with a stained negative.

Sandy King

 

[photomc]

Sorry, have not seen this and may be able to help. Last year I built a 12 blub unit using F20T12 BLB bulbs. Michael was quite helpfull at the time, but when it came time to find ballast, I had the same problem. Someone else had mentioned the Fulham Workhorse electronic ballast, Dan Smith (Wareaglemountain or something like that). Anyway, I contacted them, the website is very good and ended up using 3 of their Workhorse 7 for 12 bulbs (4 per ballast).

There is no warm up, they all start right up, and output is very good, ballast factor > 0.90. I would recommend them, and have, to anyone. They run cool compared to the mag. ballast I had used previously on a 4 bulb unit and print times range from 3 min up depending upon the negative. Of course output might be better if I had started out with BL blubs instead of BLB, but you buy what you can get.

Hope this helps.

 

[cperez]

Taking this one step further, how do your tube times compare with your spiral bulb (BLB?) setups?

With kallitype and palladium my print time with a Stouffer step wedge negative is about two minutes with a bank of BL tubes, about one minute with the AmerGraph ULF-28. Exposures for digital negatives on Pictorico are about 1/4 more...

 

[sanking]

Taking this one step further, how do your tube times compare with your spiral bulb (BLB?) setups?

From my tests I find that the spiral BLB tubes print about as fast as regular BLB tubes, assuming you place them at about 4" from the printing surface. Of couse, to do this you will need an array of spiral tubes to cover a fairly small area, say 8X10. Bu if you stack them together the spiral tubes do a good job.

Sandy King

 

[Patrick Kolb]

Here is a link to some electronic ballasts: http://www.ballastwise.com/item.asp?PID=124&FID=14&level=1
I am sorry but you have to click on the pdf file to view the description. Can someone tell me if these would work. I will be using F20T12 tubes.

The price seems almost to good to be true. Thanks to everyone that has responded.

 

[photomc]

Here is a link to some electronic ballasts: http://www.ballastwise.com/item.asp?PID=124&FID=14&level=1
I am sorry but you have to click on the pdf file to view the description. Can someone tell me if these would work. I will be using F20T12 tubes.

The price seems almost to good to be true. Thanks to everyone that has responded.

Looks like they would, the DXE220M12 is the one I would go for since it will drive 2 bulbs, the other will only drive 1. So $60 for a 12 bulb box, not bad. Think I found the Fulham's for $30 each so ended up with $90 invested.

Good luck

 

[Patrick Kolb]

Chris,
I have had the opportunity to use both the spiral bulbs and tubes. I used a step wedge and with the light source about 4 inches away, I tested for time so I would get what people call 90% black at about step 4. Given that each person has their own procedures, mine being Na2, and every system is a little different, I got the following:

Spiral bulbs, the unit had six bulbs five inches apart and four inches between the bulbs and paper, my time was 14 minutes.

BL tubes, this was a big unit with bulbs spaced about 1 3/4 inches apart and about four inches above the paper, my time was ten minutes.

Every system is different, and it would interesting to see what others have been getting.

Patrick

 

[Patrick Kolb]

I just wanted to thank everyone for their support. I just finished my lightbox and am really pleased with the results. I used 12 20-watt tubes , spaced 1 3/4 inches apart and 3 inches above the paper. Using the electronic ballasts mentioned above, I am getting a time of 4 minutes for 90% black on step 4 on my step wedge.
Thanks again and Happy Thanksgiving