Why Not Enlarge on Azo?

[Donald Miller]

quote: "On the subject of the Mercury bulb.. How do you propose to vent the heat from the bulb? Fan? Or does a Mercury bulb run cool?"


With the lamp being on continuously, I assume that there would be a need to ventilate the bulb compartment. The 138S that I have has provisions to attach tubing and a remote fan to the lamp compartment. It has an opening on top of the compartment.

[Donald Miller]

Quote:

"In general, if using tungsten lamps for print on AZO speed materials my biggest concern would be to use an exhaust fan to eliminate excessive heat. Such exhaust fans are available for the Durst equipment."

Tungsten bulbs will not provide enough UVA emission to enable enlarging. It will require a mercury vapor bulb of some type. These lamps whether they are BL or BLB fluorescent or HID mercury vapor all provide increased UVA emission. Another lamp type that may have potential are the pulsed xenon.

You are correct that many modifications incorporating higher wattages will require some type of convection cooling.

[Will S]

I just posted a print in the critique gallery. I just wanted to see if I could get it to work so I literally put something together with tape and galvanized duct work.

47 sec. exposure for a 35mm negative at F5.6 enlarged to 10" across. Lens is 50mm Componon-S. I did have to focus differently, but was able to focus using the hocus focus. Not sure if any other focusing method would work. Using a Nikkor-EL lens you can probably just switch the heads.

I did a little burning on the sand, but I kept it at a minimum because I wanted to see what the straight print looked like.

I loaded the paper in, covered the lens, turned it on for a minute, then started timing.

I'm going to try with 3 BLBs, but 2 is definitely OK.

Tried printing another neg that took times in the 1.5 minute range on VC paper @f11. It was up around 5 minutes and the burn-in was going to be more than that @f4 with the Azo. The 47 second one was about 15 sec on grade 2 using VC paper @f16. So, dense negatives aren't going to be easily enlarged.

Azo Enlarging Head for Omega D2V (and possibly others)

Ingredients:

2 20W BLB spirals
1 15W white light/normal flourescent spiral
gaffers tape
4" to 6" galvanized duct adaptor ($8.75US)
3 electric light sockets (salvage from old lamps)

Instructions:

Tape all 3 bulbs together with gaffers tape. I used some in between as spacers so that they were not touching.

Connect up the light fixtures to each bulb. Tape the 3 cords together at the top.

Place all three bulbs into the 6" diameter side of the duct joint. Get them positioned correctly (just above the bottom) then use gaffers tape to construct a "lid" that is taped to the sides of the duct and to the bulbs.

Remove old lamphouse. Place Azo lamphouse into the 4 inch diameter round hole. I had to scootch it a bit to get it to drop in. Drape cords over top of enlarger so that bulbs are held up enough.

Plug in and turn on. 1 minute warmup time needed. Don't leave on for too long!

Total cost: circa $35

Best,

Will

[Mike-D]

Will,

Interesting. By my rough calculations, you are getting about a stop and a half advantage with the UV head. If memory serves me right then Azo has a ISO-P of 4 and typical VC papers are in the 250 range with a filter.

It might be a worthwhile test just for fun if you tried to enlarge the same negative on Azo using your standard light source.

For exposure did you just use two standard-base spiral BLB lamps? Also, what kind of diffuser did you have in the light path?

I have a couple of ideas for a UV head but I am still trying to work them out, so any data is helpful.

Thanks for posting your results,

Mike D

I just posted a print in the critique gallery. I just wanted to see if I could get it to work so I literally put something together with tape and galvanized duct work.

47 sec. exposure for a 35mm negative at F5.6 enlarged to 10" across.

...

Will

[Will S]

Will,

Interesting. By my rough calculations, you are getting about a stop and a half advantage with the UV head. If memory serves me right then Azo has a ISO-P of 4 and typical VC papers are in the 250 range with a filter.

It might be a worthwhile test just for fun if you tried to enlarge the same negative on Azo using your standard light source.

For exposure did you just use two standard-base spiral BLB lamps? Also, what kind of diffuser did you have in the light path?

I have a couple of ideas for a UV head but I am still trying to work them out, so any data is helpful.

Thanks for posting your results,

Mike D

Yes, the spiral blbs recommended on the thread here and at michaelandpaula.com 20W BLB

I did not use a diffuser. I tried using one, but found it wasn't needed. I took an old plastic groundglass that I had and just laid it over the top of the condenser as a diffuser. I found it added about 1 stop of light loss. Removing it didn't seem to make a difference, so I just left it out. :-)

A "real" head would probably need a diffuser and reflecting material inside of it to get all of the light from 4 bulbs going down, but I'm happy with my 3 bulb frankenstein monster for now.

Given that these spiral blb 20w bulbs work I would think someone could actually manufacture a head fairly cheaply. At least, less than $250 or so depending on the design. Of course, there has to be someone willing to take the risk financially.

Thanks,

Will

[Mike-D]

Thanks, Will.

Very interesting. I wonder if you took out the condensers whether it would make any difference. The glass may or may not attenuate the UV light.

My own idea is to try BL as opposed to BLB bulbs. These are bugzapper replacement lamps. The disadvantage, of course, is that I would have to either dissect a couple of zappers or figure out how to wire up the ballast and starters. I am doing this for a 5x7 enlarger so I have to cover more area. The BL bulbs should give off a little visible light for focusing.

Good luck and let us know how the trials are going.

Mike D

Yes, the spiral blbs recommended on the thread here and at michaelandpaula.com 20W BLB

I did not use a diffuser. I tried using one, but found it wasn't needed. I took an old plastic groundglass that I had and just laid it over the top of the condenser as a diffuser. I found it added about 1 stop of light loss. Removing it didn't seem to make a difference, so I just left it out. :-)
...

[Will S]

I thought Sandy King reported that the BL bulbs didn't work, but maybe I'm remembering that wrong. It was probably in the thread over at michealandpaula.com.

I'll try taking the condensers out and see what happens. I just assumed that condensers were condensers.

Thanks,

Will

[Will S]

I thought Sandy King reported that the BL bulbs didn't work, but maybe I'm remembering that wrong. It was probably in the thread over at michealandpaula.com.

I'm wrong. He was talking about the HID bulbs or something else.

Thanks,

Will

[Mike-D]

I did read that incandescent BL bulbs won't work because they are very deficient in UV light. I thought that fluorescent ones would work, but I must say I haven't tested any of this. I guess if I do go to the trouble of constructing a head I guess I better make sure that it takes different kinds of lamps.

Thanks,

Mike D

I thought Sandy King reported that the BL bulbs didn't work, but maybe I'm remembering that wrong. It was probably in the thread over at michealandpaula.com.

I'll try taking the condensers out and see what happens. I just assumed that condensers were condensers.

Thanks,

Will

[Gustavo_Castilla]

I don that in my cheap little besler C760
from 35 mm negs with no problems exposure was about 45 sec and up to a couple of min
and a few people here have seen the prints they look and work fine just ask toddstew
he has seen the when I was In Sta Fe last week the lens setting was something like f8
and the developer amidol straight