Large format Enlarger Advice - Please [Archive] - Large Format Photography Forum

LeeSimmons

19-Jul-2016, 14:41

Looking to delve into collective wisdom as I am just about all the way into a new first time darkroom setup.

I shoot mainly 4x5 and have been digitally printing and recently purchased an 8x10 kodak 2d with 5x7 back.

I've been building a darkroom and purchased an old elwood 8x10 enlarger(the wood and cast iron one) with an older aristo head. The head requires graded paper only and can be upgraded to vc for $500 from aristo. The neg holders are dodgy as they are mat boards sized to fit the 8x10 holder and the negs easily move around. The precision is ok but far from smooth. I also have a recently purchased lpl 6700 dxl which I thought would be good for paper flashing and the occasional small format printing.

After spending time with the camera I think 8x10 format will be for portrait contact prints only possibly using 5x7 and 4x5 for lanscape fieldwork.

That was all ok then a locally available Durst 138s with full set of condensers and holders is on the table.

I am looking at my 3rd enlarger before making a single print. The 5x7 enlargers don't seem to come up that often and I'm thinking it would replace the other two with the obvious exception of 8x10.

I'm quite a ways down this rabbit hole and would appreciate some sane advice.

Regards Lee

Peter De Smidt

19-Jul-2016, 14:45

If you can find the space, get the Durst. It's a completely different (and better) class than the Elwood. It will be much easier to align, it will stay that way, and it'll be great even for smaller formats.

LeeSimmons

19-Jul-2016, 15:15

Thanks Peter,

Drew Wiley

19-Jul-2016, 15:58

This is a dogsled versus Ferrari option.

agregov

19-Jul-2016, 17:18

I'm just spinning up into 8x10 myself so I can't comment much on enlarger choices there. Though, the Elwood looks pretty old school. A modern 8x10 enlarger would seem a better bet--but as Drew suggested, they will be pricey. Given you are primarily a 4x5 shooter, I would ditch the medium format LPL enlarger in favor of one of the Saunders 4x5s (4500/4550XL). They are quite well regarded among forum users. I have two myself. I would spend some time printing 4x5 before worrying about 8x10. The 4500/4550's are also modern enlargers so you'll get an idea how a up-to-date 8x10 enlarger should perform. You could make a call at that point whether you want simply contact print or upgrade to something like a Durst for 8x10. As for the 138s, they are also quite well regarded in the forum. If you have a fully equipped version, that would make a great 4x5/5x7 enlarger. Start with doing most your printing there and then figure out 8x10 later. In the 138s scenario, I'd still probably ditch the 6700 LPL. No sense it taking up space in the darkroom. Keep things simple. Good luck.

HMG

19-Jul-2016, 18:14

I've read (but have no direct experience) that 40cc Y filter will allow use of the older cold light bulbs with VC paper. Search and you'll see some commentary here and elsewhere.

LeeSimmons

19-Jul-2016, 19:13

Thank you for the feedback.

I'll go with the 138S.

I would like a 4x5 lpl but none are currently available in my areaand the 138s does the 5x7 as well.

Got a chuckle at the Ferrari analogy.

Thank you for your thoughts.

Regards Lee

Luis-F-S

19-Jul-2016, 20:28

I've been building a darkroom and purchased an old elwood 8x10 enlarger(the wood and cast iron one) with an older aristo head. The head requires graded paper only and can be upgraded to vc for $500 from aristo.

I'm quite a ways down this rabbit hole and would appreciate some sane advice.

Regards Lee

If the Elwood $500 "VC upgrade" consists of new tubes, I wouldn't waste the money. First, I'd try a 40 CC yellow filter. Should be fine with the older tubes and VC paper. As noted above, I'd look into an LPL 4x5 enlarger, or at least the Durst 138S as long as it's complete and has all the pieces parts, ie, Nega 138 holder with glass, bulb and some lens boards, and at the right price. Otherwise these items get pricey and hard to find. The Durst is a fine enlarger, and I have one stored, but unless if you're going to shoot 5x7, I'd stick with the 4x5 LPL as Andrej suggested. They occasionally come up on Craigslist, are much newer and user friendly esp with the VC head. L

John Kasaian

19-Jul-2016, 23:09

Elwoods work. They are easy to fix unless a casting breaks. They can also fit easily into a normal size room and be supported by a normally constructed floor. And they can be found cheap--that is the charm of the Elwood. Most you'll find have already been well hammered.
Operating an Elwood takes a different mind set than a modern, precision built enlarger. An Elwood is sort of like a Stearman, while a Durst is more like an Airbus. Both will "get you there" but it helps to have a sense of humor (and a lot of time on your hands) when flying a Stearman.
153051 versus 153052

Jim Andrada

20-Jul-2016, 19:47

I had a 138S for - well, several decades. I was taking a photo in a local park with my 5 x 7 and had my head under the dark cloth when I saw a pair of feet. Looked out from under and the gentleman who was attached to the feet asked if I might be interested in a 5 x 7 enlarger. Up to then I'd been contact printing so I took him up on it - I think I paid $500 for it. Somehow I got it into an old BMW 2002 (in several pieces,) got it home and built a darkroom around it. Wonderful piece of equipment. I moved several times for work and didn't have a way of setting up a darkroom in the newest house so I donated it to a friend who was associated with the the Institute of Contemporary Native American Art in Santa Fe where they wanted to use it for murals. It's probably still there. It had grooved wheels so it could run on rails with the head swung 90 degrees so it fit the bill for what they wanted.

I think you'll be really happy with it.

docw

20-Jul-2016, 20:52

I am going to caution you against the 138. I have one and have never been able to get it working properly because it is impossible to find a decent light source. The original bulbs are a fortune and hard to find. I tried to build an LED replacement but I really don't know what I am doing. The only non-original bulbs that work are high wattage and extremely hot so you have to build some kind of ventilation system. Every bulb I tried, other than the 500 watt ones, had serious light drop-off. So unless you have some mechanical skills, the Durst could be a huge pain in the arse. Furthermore, any replacement parts or extra parts you might want usually cost a fortune. I am trying a few more solutions before I get rid of mine, but as it is, it just takes up space. I would love to find an Ilford VC head for it, but they don't come up very often. Now I contact print 5x7's and print 4x5 on a DeVere.

I can't believe that anyone would design an entire enlarger based on a particular bulb (which is now impossible to find)!

Good luck.

Sal Santamaura

20-Jul-2016, 21:46

I am going to caution you against the 138. I have one and have never been able to get it working properly because it is impossible to find a decent light source...Incorrect:

http://heilandelectronic.de/led_kaltlicht/lang:en

Possible regardless of which 138 head configuration one has. Easy to pay for is another matter. :)

Jim Jones

21-Jul-2016, 05:26

Ah, the Elwoods! Hauling a 5x7 home atop a '73 VW bug was an adventure. It had to sit on the darkroom floor to clear a low ceiling. After losing it and the darkroom in a fire, I quit using 5x7 and bought a much more elegant and versatile DeJur 4x5. Basic relics like the Elwood and DeJur can be easier to maintain and modify than more sophisticated equipment.

John Kasaian

21-Jul-2016, 06:45

bob carnie

21-Jul-2016, 06:53

Hi Sal thanks for the link- do you know if they are making these units for Contact printing, Silver and Pt Pd?
Incorrect:

http://heilandelectronic.de/led_kaltlicht/lang:en

Possible regardless of which 138 head configuration one has. Easy to pay for is another matter. :)

Sal Santamaura

21-Jul-2016, 07:50

Hi Sal thanks for the link- do you know if they are making these units for Contact printing, Silver and Pt Pd?Bob, I don't recall seeing or hearing of any such items. I've got a Heiland on my Beseler 23CIII that I use for contacting silver.

That said, I encourage you to contact Juergen Heiland and ask what he can do for you. My LED source was one of the earliest he made, elegantly adapted to the 23C long before mounting kits for the long list of enlargers on that page were developed. He can probably custom-build whatever you need.

Drew Wiley

21-Jul-2016, 08:25

A greater variety of heads were made for the Durst 138 than any other enlarger I can think of, both by Durst and aftermarket manufacturers. Since the chassis is
so solid, they are in fact one of easiest enlargers to customize with your own head if desired.

Luis-F-S

21-Jul-2016, 10:25

I am going to caution you against the 138.

I can't believe that anyone would design an entire enlarger based on a particular bulb (which is now impossible to find)!

Good luck.

The G40 150 watt bulb should more than suffice, esp since you're printing 4x5. You should not need ventilation though I would still use a fan on the head. I have 3 of the 300w original bulbs which I use with a dimmer both to lower the intensity and extend the bulb life. Also have the Aristo D57 cold light head for it which works fine. The Durst 138S is a wonderful enlarger if you have all the parts (carrier, boards, glass, etc.) and in if good condition. They last forever, my 40 yo SM-183 looks new!

You can also go with the LPL 4500 enlarger and the VCCE head which was suggested if you don't want to deal with the Durst's idiosyncrasies.

docw

21-Jul-2016, 11:09

Incorrect:

http://heilandelectronic.de/led_kaltlicht/lang:en

Possible regardless of which 138 head configuration one has. Easy to pay for is another matter. :)

Thanks, Sal! This is exactly what I am looking for. Now if Heiland would only tell us how much it is, lol. Their prices seem to be a Big Secret or, at the very least, they don't make it easy to find them. That makes my wallet nervous, but one can't be faint of heart in the LF world.

Sal Santamaura

21-Jul-2016, 11:12

.Now if Heiland would only tell us how much it is...From the page I linked, just click on the SUPPORT tab, then the Price List link. You'll end up here:

http://heilandelectronic.de/files/documents/Heiland_pricelist_2016_05.pdf

Remember, I did write

...Easy to pay for is another matter. :)

docw

21-Jul-2016, 11:15

The G40 150 watt bulb should more than suffice, esp since you're printing 4x5. You should not need ventilation though I would still use a fan on the head. I have 3 of the 300w original bulbs which I use with a dimmer both to lower the intensity and extend the bulb life. Also have the Aristo D57 cold light head for it which works fine. The Durst 138S is a wonderful enlarger if you have all the parts (carrier, boards, glass, etc.) and in if good condition. They last forever, my 40 yo SM-183 looks new!

You can also go with the LPL 4500 enlarger and the VCCE head which was suggested if you don't want to deal with the Durst's idiosyncrasies.

I got this enlarger to do 5x7 and was mightily disappointed when it didn't do the job. I didn't know about the LPL but I will take a look. I am also going to track down the Heiland source mentioned by Sal. I really hope I can get this thing running productively.

Ooops. After posting, I realized that the LPL 4500 must be for 4x5 and not 5x7. It is the latter that I want.

LeeSimmons

21-Jul-2016, 17:20

Thanks for keeping the thread alive.

Still waiting to hear back from the 138s guy after pulling the trigger.

In the meantime I may have a line on a lpl 4x5 then I'd leave the elwood for 5x7 and 8x10 and the LP for 4x5 and smaller.

Either way the thread helped as I hate spending money with no experience. Thanks again all for the humor and advice. It as nudged me in the direction I need to go.

Enlarger strapped to the top of a VW. Brings a smile to my face. The crazy things we do in this hobby. Much appreciated.

Lee

sepiareverb

21-Jul-2016, 17:35

Keinzle.

I hacked an old zone VI with the 810 conversion kit with a real pro light source from Keinzle. I'd contact them as they make 5x7 units today. Best light source I have ever used, and I worked in a lot of pro labs back in the day.

quine

21-Jul-2016, 17:41

The PH211/212/213 bulbs work fine on the L138 (with increased contrast). Less than $5 at B&H.

jnantz

21-Jul-2016, 18:38

there is a color correction filter you can stick between the light source and the paper
to "correct" the older aristo heads, and the old omegalite heads to work with VC paper.
i have searched a bit for the reference but can't seem to find it. voltarc ( who owns aristo now )
might sell and install a tube for you to replace it with a more modern one too.
i don't think rick metta is there anymore, I'm not sure who you should call and ask for.
if you want to go that route maybe someone here can suggest who to talk with, or what filter to use..

good luck
john

ps. john kasaian is on the money !

docw

21-Jul-2016, 20:38

The PH211/212/213 bulbs work fine on the L138 (with increased contrast). Less than $5 at B&H.

No drop-off with 5x7?

Luis-F-S

21-Jul-2016, 20:55

No drop-off with 5x7?

Yes, you need a much larger bulb envelope for 4x5 & 5x7 than a PH 2xx bulb to have even illumination. That is why I suggested the G40. The G40 bulb globe is around 4.5" diameter, the PH2xx globe is 2.5". Allen in Montreal did quite a bit of comparison for available bulbs in this thread:

http://www.largeformatphotography.info/forum/showthread.php?74895-Durst-138S-Replacement-Bubs

You can see in this photo from one of Larry's posts that the G40 (on left) is much larger in diameter than the PH 2xx bulbs and approaches the original Durst bulb on right (4.25" dia). The PH2xx bulbs may work for 135 & Medium Format, but won't illuminate very evenly for large format on the 138S. L

153114

docw

21-Jul-2016, 21:04

Yes, you need a much larger bulb envelope for 4x5 & 5x7 than a PH 2xx bulb to have even illumination. That is why I suggested the G40. Allen in Montreal did quite a bit of comparison for available bulbs in this thread:

http://www.largeformatphotography.info/forum/showthread.php?74895-Durst-138S-Replacement-Bubs

You can see in this photo from one of Larry's posts that the G40 (on left)is much larger in diameter than the PH 2xx bulbs and approaches the original Durst bulb on right. The PH2xx bulbs may work for 135 & Medium Format, but won't for large format. L

Luis, I remember that thread and I don't remember why now, but the G40 did not work all that well. I had a long conversation with Larry about LED's but I just don't have the skill to do it on my own. I am hoping to hear back from Heiland about their LED light source, and I am hoping that it won't cost an arm and a leg.

Luis-F-S

21-Jul-2016, 22:22

I got this enlarger to do 5x7 and was mightily disappointed when it didn't do the job.

Don't understand the problem. Mine printed 5x7 just fine both with the Thorn bulb and the Aristo D57 Cold Light head. You can always remove the condenser head and put an oversized 5x7 - 8x10 Aristo cold light head in its place if you want. L

Michael R

22-Jul-2016, 06:09

Luis, I remember that thread and I don't remember why now, but the G40 did not work all that well. I had a long conversation with Larry about LED's but I just don't have the skill to do it on my own. I am hoping to hear back from Heiland about their LED light source, and I am hoping that it won't cost an arm and a leg.

Price list (LEDs start on page 4):

http://heilandelectronic.de/files/documents/Heiland_pricelist_2016_05.pdf

Tin Can

22-Jul-2016, 06:18

Yes, I have seen the cost of Heiland before. Impressive.

Perhaps cheap by historical LF pricing.

Has anyone seen Heiland LED heads in action?

Price list (LEDs start on page 4):

http://heilandelectronic.de/files/documents/Heiland_pricelist_2016_05.pdf

Sal Santamaura

22-Jul-2016, 08:26

In another thread, Kirk posted that "nobody reads the prior posts." I'm not sure nobody does, but very few do. :D

...I am hoping to hear back from Heiland about their LED light source, and I am hoping that it won't cost an arm and a leg.

From post #20:

From the page I linked, just click on the SUPPORT tab, then the Price List link. You'll end up here:

http://heilandelectronic.de/files/documents/Heiland_pricelist_2016_05.pdf...

also

...Has anyone seen Heiland LED heads in action?

From post #16:

...I've got a Heiland on my Beseler 23CIII that I use for contacting silver...

:D:D

docw

22-Jul-2016, 09:17

Don't understand the problem. Mine printed 5x7 just fine both with the Thorn bulb and the Aristo D57 Cold Light head. You can always remove the condenser head and put an oversized 5x7 - 8x10 Aristo cold light head in its place if you want. L

Luis, of course the enlarger works fine with the original bulb (what are they now? 300 bucks?). And I am sure it works just as well with the Aristo Cold Light head or, as you suggest, the 8x10 head, neither of which is cheap. And I just checked out the Heiland price. Sit down before reading further. Their LED light source for the 138s is just a hair over 2000 USD, without shipping. At that price, I am pretty sure I could hire someone to build me a light source and probably have a lot of change. That may well be the route to go.

That is the heart of the problem. I have a complete Durst 138s sitting in my darkroom, all ready to go. It has the right condensers, a Schneider lens, etc. All I need is a bulb which is normally a solution in the $10-$20 range, but all of the suggestions so far are very, very expensive solutions to what should be a very inexpensive problem.

If I need a light source for my Omegan D5XL or my Devere 504, I don't need to take out a loan. Hence my frustration with the Durst.:mad:

I am going to try again with the G40 bulb and see if I can't somehow get even light out of it. I will let you know what happens. Wish me luck!:)

Drew Wiley

22-Jul-2016, 09:41

Even if you only come close with a substitute bulb rather than the original specified opal bulb, you can always slip in a piece of transluscent white plexiglas to
diffuse the light and thereby make the field of illumination even. You don't have to strictly work on the condenser principle alone.

Luis-F-S

22-Jul-2016, 10:04

Luis, of course the enlarger works fine with the original bulb (what are they now? 300 bucks?).
I am going to try again with the G40 bulb and see if I can't somehow get even light out of it. I will let you know what happens. Wish me luck!:)

I don't have personal experience with the G40 bulb since I didn't need to use one, but I did buy a case of them for the future, just in case. I put my Durst in storage when I set up my DeVere 5108 because I can only fit one floor standing enlarger in my darkroom. I've kept the SM-183 in case I can add on to my darkroom or if someone is really interested in it.

My 3 Thorn bulbs are 300 watt. I would always dim them to lower the intensity and preserve the bulb, or I would just use my D57 cold light insert. Two of the bulbs are unused. As Drew suggests, you may be able to use a thin piece of milk glass or diffusion glass to even out the light if needed. Even a gel diffusion filter may work sandwiched between two pieces of glass in the filter holder. I've got an old Aristo 5x7 cold light head I'll give you for the shipping if you want to try and adapt it.

There was a fellow in the English forum who was trying to get 300 W "Durst" bulbs custom fabricated but unfortunately that effort was not successful. See:

http://www.apug.org/forum/index.php?threads/durst-1840-184-and-138-enlarger-lamps-news.129970/

Do let us know what you find out. Good Luck. L

quine

24-Jul-2016, 17:20

I've never had illumination issues using the smaller 211/212/213 bulbs for 4x5 if the bulb position is properly adjusted. There is less margin of error for this than with the larger Thorn bulbs (so you may need to adjust more often), and the contrast is inherently higher. Note that even a tiny point-source bulb can cover 4x5 and 5x7 if you get the bulb position correct.

Luis-F-S

24-Jul-2016, 20:42

Good to know.

quine

25-Jul-2016, 21:39

So, in the interest of "science", I took some measurements off my enlarger using a photometer to compare a 300w Thorn bulb with a PH212 bulb. I zeroed the photometer to the center of the negative, then measured the density at each of the four corners of the negative for two different enlarging lenses, negative sizes, and condenser combinations. Here's what I got:

EL Nikkor 150mm f/5.6 @f/8, Latico 240/Latico 200, 4x5:
300w Thorn = (0.20, 0.20, 0.20, 0.22)
PH212 = (0.23, 0.20, 0.21, 0.23)

Componon 210mm f/5.6 @f/8, Latico 240/Latico 240, 5x7:
300w Thorn = (0.30, 0.30, 0.28, 0.28)
PH212 = (0.28, 0.25, 0.26, 0.28)

where (LL, UL, UR, LR) are the four corners of the negative.

So, for 4x5, the PH212 bulb has .0125 additional density in the corners relative to the Thorn bulb. This is 1/24th of a stop, which seems inconsequential compared to the fall off from the enlarging lens.
The Thorn bulb actually had more fall off in my little experiment at 5x7 -- I'm at a loss to explain this, but there it is. I was expecting the PH212 bulb to be measurably (but not visibly) worse at 5x7.

Here is the record of my experimental conditions for those who would like to reproduce my results:

bulb forward
height = 570mm
table depth = 85mm
enlargement ~ 4x
heat-abosrbing glass
Latico 240/Latico 200
LAPFE 4x5
90% voltage

bulb forward
height = 570mm
table depth = 483mm
enlargement ~ 4x
heat-abosrbing glass
Latico 240/Latico 240
LAPFE 5x7
90% voltage

Welch Densichron
3/8" aperture
Blue Probe

Note that it's imperative that the PH bulbs be centered on the lens. It's almost impossible to get the Thorn bulb off center enough for it to matter.

Here's how I center a bulb:
1) Focus the lens on the negative carrier at a reasonably large size (e.g., 16x20).
2) Remove the negative carrier.
3) Move the bulb all the way back so that you get some vignetting on the corners. If you don't get any vignetting, try a different enlargement factor.
4) Adjust the vertical bulb position so that you get equal amounts of vignetting on the top and bottom (i.e., LL = UL, LR = UR).
5) Adjust the horizontal bulb position so that you get equal amounts of vignetting on the left and right.
6) All four corners should have equal amounts of vignetting now. If not keep adjusting horizontal and vertical.
7) Move the bulb forward until the vignetting goes away. Back off if you get "blue stuff" (tm) in the middle of the field.
8) Replace the negative carrier.

Note that you may need to adjust the front/back distance if you change the enlargement height significantly (but every time if you use a clear bulb). You should only need to re-center if you change bulbs.

Luis-F-S

26-Jul-2016, 10:12

Thanks Andrew for taking the time to do this. As I said, my Durst SM-183 is in pieces, so I could not run this. It is good to know as so many people have had bulb issues with the L-138 which is a great enlarger. Was curious if you'd ever tried the G40 bulb? In the interest of science, it would be good to know. Same wattage as the ph212, but a much larger bulb envelope.

Thanks, L

quine

26-Jul-2016, 11:37

Yes, Luis, I have a G40 bulb at home -- I'll give it a try. I'll also try the cold-light head for comparison.

Note that when I say "negative" above, I mean "negative carrier" -- I didn't have a piece of film in the carrier.

Jim Andrada

28-Jul-2016, 22:13

Yes - it's all coming back!!!!! Bulb position, as quine says, is very important. Damn but I miss that enlarger.

quine

31-Jul-2016, 18:25

Ok, I repeated my measurements with 3 different light sources. This time, I elevated the far side of the probe by 1 inch to get rid of the shadow cast by the probe aperture, which I think was exaggerating the overall center-to-corner fall-off measurement. Note that tilting the probe also reduces the distance to the light source, so these measurements might be a little too optimistic, but it should be safe to compare them to each other. To keep the probe orientation consistent, I ran the cord through the center of the table when taking each corner measurement. For the cold-light measurements, I kept the LACOLI (V54 bulb) on until the reading stabilized to avoid measuring the warm-up.

Here are the measurements (LL, UL, UR, LR):

4x5 PH212: (.02, .01, .02, .04)
5x7 PH212: (.11, .08, .08, .10)
4x5 G40: (.03, .04, .06, .04)
5x7 G40: (.11, .11, .13, .12)
4x5 LACOLI: (.06, .08, .11, .07)
5x7 LACOLI: (.18, .22, .26, .22)

FWIW, I noticed that the G40 bulb had significantly less light output than the PH212, despite them both being rated at 150w. The G40 is similar to the Thorn bulb in that it can be rather far out of position and still provide usable illumination. I was careful to center it for these tests, however.

I'm surprised again that the more diffuse light sources seem to have more light fall off than the more collimated light sources. I'm wondering whether this might be due to differences in flare?

quine

1-Aug-2016, 10:44

FWIW, I found a probe tip this morning with a built-in diffuser that seems to give more stable readings in the corners. I'll try again with it and report back.

Luis-F-S

1-Aug-2016, 11:13

FWIW, I found a probe tip this morning with a built-in diffuser that seems to give more stable readings in the corners. I'll try again with it and report back.

How does the center illumination compare with the corners? Any hot spots? From your readings above, it appears that the G40 has half the fall-off of the Durst Lacoli which was a Durst product. Thus, it would appear that the G40 would be usable as long as centered and the light output sufficient. Thanks, L

quine

1-Aug-2016, 21:02

Here's another set of readings using the translucent-tipped probe. Using it on the G40, I can trace a relatively smooth gradation from the center of the negative carrier to the corners (no detectable hot spots). It also isn't sensitive to the orientation of the probe on the baseboard, which is something I didn't like about the open-aperture tip. I threw in measurements for a 10w halogen point-source bulb this time.

Notation is (LL_corner, UL_corner, UR_corner, LR_corner) = mean_of_corners. Units are density.

4x5 G40: (.06, .07, .08, .07) = .07
5x7 G40: (.06, .06, .06, .06) = .06
4x5 PH212: (.08, .06, .10, .12) = .09
5x7 PH212: (.12, .10, .12, .14) = .12
4x5 10w halogen: (.04, .02, .07, .08) = .0525
5x7 10w halogen: (.07, .08, .10, .13) = .095
4x5 V54: (.11, .12, .14, .12) = .1225
5x7 V54: (.14, .14, .14, .13) = .1375

The G40 bulb turns in a strong performance -- total light fall off is about 1/5 stop. The point-source bulb does surprisingly well, at least at 4x5. The cold light again does relatively poorly -- I'm not sure why this is the case. The PH212 is decent at 4x5: only 1/15 stop worse than the G40. At 5x7, it's only slightly better than the cold-light head.

In any case, I think that all of these are usable light sources for pictorial work -- the difference between the best and worst performance is only about 1/5 stop.

Luis-F-S

2-Aug-2016, 09:26

Great! Thank so much Andrew for taking time to do this. This should hopefully quell the fears of those who say that there are no usable bulbs for the L-138. Since some of these bulbs are also available in 250w or higher, they should work for those who need more light output than the G40 provides. Just don't forget to ventilate the housing with a blower! Since the ph212 turns in a slightly better performance than the Durst Lacoli, it should be fully usable. I never had any issues with the Aristo D57 which should be very similar to the Lacoli. With the higher wattage bulbs, you can still dim the down slightly and put a piece of milk glass in the filter holder to even things out even more! Thanks again! Luis

Mark Sampson

2-Aug-2016, 16:19

Tin Can

2-Aug-2016, 16:28

When, in a past life, I used a Fotar 10x10 with a Super-Chromega-F 10x10 color head, we had unevenness problems- due to the fact that the SC-F has 4 250watt ELC lamps in a row. So we made an ND correction mask. We measured the falloff, set the enlarger to 1:1, and exposed a sheet of 11x14 line film. When we found an exposure that reached the right density... about .15 if I remember, we put it above the negative stage and voila! perfect evenness across the field. You can still get copy films that would work... if you have measuring equipment this approach would be worth a try.

I have an F and one look at the design sent me into DIY. I never even hooked it up.

I figure the F was made for low ceilings, a marketing request, nay order from bean counters.

Mark your 'fix' is a fine one.

I have taken to pencil, paper to glass, hand drawing center filters for single bulb enlargers. And checking efficacy with Sekonic spot meter. We work with what we have and can afford.

quine

2-Aug-2016, 21:05

Hopefully my last post on this:

I went back to the 300w Thorn bulb and tested again using the diffuser-tipped probe. The results were rather surprising:

4x5 300w Thorn: (09, .08, .07, .08) = .08
5x7 300w Thorn: (.15, .14, .11, .11) = .1275

which is actually worse at 5x7 than the PH212(!)

This got me to thinking that my Thorn bulb was taken out of a professional darkroom and probably had seen lots of use. You can actually see marks on the opal coatings if you turn the voltage way down, whereas the PH212 bulb was comparatively new, me being an amateur. I've also read that it used to be a thing among Durst users to turn the bulb socket so as to orient the freshest part of the bulb to project on the negative (Durst L138 sockets are designed to rotate). So I also tried a brand-new PH211 bulb for comparison:

4x5 PH211: (.08, .06, .07, .08) = .0725
5x7 PH211: (.12, .10, .09, .11) = .105

which represents a marginal improvement over the PH212 readings above (my assumption here is that the PH211 and PH212 have the same construction and that only the filaments are different).

Note also that the best overall performer of the previous bunch, the G40, was essentially new as well.

This all leads me to think that the condition of the individual bulb has as much to do with the evenness of the illumination as the size of the bulb, and that if you really care about getting that extra 1/5 stop in the corners, you're better off with brand-new G40 than a well-used Thorn. Personally, I'll probably stick with the PH bulbs, since I almost always end up burning in the edges of my prints anyway...

Mark Sampson

3-Aug-2016, 19:09

Randy, that 'fix' that I so badly described was not by me, rather by a very inventive colleague. At Kodak in those days we were doing some rather precise engineering/research work and even enlarger illumination was critical to several projects. One I can still explain was to make 40x40 color prints from 9x9" aerial color negatives for evaluation and display. We lost less than 1/2 stop brightness that way (the Sc-F had plenty to spare) and it sure made life easier for a long time. c.2008 they dismantled and sold that enlarger off.. I sure hope whoever got it saved and used the mask. The OP may be able to make something similar using Ilford Ortho film or a similar emulsion. A few tries should get it figured out, even without access to sophisticated instrumentation.

Tin Can

3-Aug-2016, 20:16

Mark, A hot shot engineering dept can do a lot. I was a tech in one. I used 100's of rolls of 12" Fuji Film.

It wasn't light sensitive but self developing pressure sensitive.

Never found a good artistic usage...

docw

4-Aug-2016, 08:02

This is a great thread! My 138 has been used largely for its easel, i.e., a flat surface in a darkroom that accumulates junk that won't go elsewhere, but I am now inspired to take another run at it. Bulbs have arrived, and now I have a PH212 and a G40 ready to go for testing the 5x7 format. I also have a piece of diffusing glass, if necessary. I will be using an Ilford EM-10 to measure the light. I would like to set it up so that I can print up to 16x20. I am assuming that if I get the bulb in position to do 16x20 evenly, it will be ok for any smaller enlargements.

I hope to have this done within a few days.

docw

6-Aug-2016, 20:28

Before I even got the chance to plug in bulbs to test, a friend showed up with an LED light source he has been working on (partly inspired by Larry Gephardt). It is just a test version with 6 LED's but so far, the results are encouraging. He arranged the LED's in a circle at first but there was too much drop off so we put them in two rows of three. We also used opal glass instead of the heat absorption glass. We had to put the LED's as close to the glass as possible to get even illumination. The was still a drop off at the edges of about 1/3 of a stop or slightly more, so we want to experiment a little more. We are going to use two rows of LED "stars" (three LEDs mounted together) for a total of 18 LED's which we hope will allow us to get farther back from the glass and even out the illumination.

I sure hope this works. If it does, it will be a very inexpensive solution to a real PITA problem.

Tin Can

6-Aug-2016, 21:44

docw

7-Aug-2016, 10:05

Did you see this link in another thread? I plan to copy or improve this design. http://jbhphoto.com/blog/2016/07/02/leds-vc-printing/

Randy, thanks for this! This is very exciting.

Tin Can

7-Aug-2016, 10:19

Randy, thanks for this! This is very exciting.

I think so also.

Last night I recovered a recycled Saltzman head part which will work for me as enclosure and heat sink.

We should move this conversation to a new DIY thread. Please do the honors as I won't have anything for some time.

quine

9-Aug-2016, 07:19

docw asked in a PM about equipment for measuring light fall off. My response went over the 2000-character limit, so I'll put the bulk of it here for posterity:

I used a Welch Densichron for my tests. There are currently a few of these listed on the evil auction site at various prices. One listing looks like it has a probe with a diffuser tip that one could use to replicate my measurements. Another listing looks like it has calibration targets for the reflection head, so you might get a reflection densitometer thrown in as well. Note that that these are vacuum-tube technology from the 1950's, so you'll be taking a risk WRT whether it's in good working order.

The Densichrons have markings in .02 density units, and you can use the space in between them to get .01 precision. More importantly, once calibrated, they actually seem to be _accurate_ to +/- .01 density based on my readings from a calibrated Stouffer step wedge. You can even use it as a transmission densitometer with a separate (but bulky and more rare) "transmission unit".

The probes normally come with a set of apertures that let you tune the sensitivity, but I found that if you let the light hit the photo tube directly, it is very sensitive to the orientation of the probe. This is fine if the probe is in a fixed position, but bad if you want to move it to the corners like I did. So, you will want to have some kind of diffuser in place if you go this route.

I would think that the Ilford EM10 would be usable for this, but the markings aren't linear, so you would need to calibrate your own scale. e.g., go through all of the click stops on a given enlarging lens and see where they fall on the EM10 dial. It should be reasonably accurate to use linear interpolation between measured click stops. Also, don't change direction when changing click stops.

Some alternatives to the Densichron that come to mind:

Lektra also made a photometer, but I haven't seen them on eBay. Markings in 1/3 stop, IIRC.
Some higher-end color analyzers (e.g., Beseler 3 series?) have readings in density units. I can't vouch for their accuracy.
The old Gossen Luna Pro has a baseboard photometer attachment and markings in 1/3 stop. You should be able to interpolate between these to get 1/6 stop accuracy (= 0.05 density). These are quite inexpensive now because they're calibrated for mercury batteries. However, the battery issue shouldn't matter for this application because you'd be taking relative readings.

I would think that any of these would be fine for determining whether or not a given bulb is "good enough" for day-to-day use, but maybe less useful for determining which bulb is the best of a given bunch.