Using an Elwood 5x7 to make big prints of 4x5s

[coisasdavida]

Hello there,

Just a quick question pointed at Elwood 5x7" users, if there is any still around.

I have an Elwood with the proper buld and diffusion glass in place. It came with a 190mm Wollensack and works very nice with that and 5x7" negatives.

4x5" negatives printed in the same setup are fine, but small.

I made a second lensboard and placed a 150mm lens on it planning to use it with 4x5" negatives and big prints, knowing some trouble would appear at some point.

Well, it did. The head and bulb were probably designed to work with a 180-190mm lens. With the 150mm I get a giant hot spot.

My first idea was to come up with a ring, 2-3 inch tall, on top of the negative stage, placing the head and buld higher. My other idea would be to canibalize a Meopta head and steal its bulb height adjusting system and place it on the Elwood.

Has anyone faced this problem? What did you do?

 

[Jim Jones]

I would have thought a diffusion Elwood would accept the shorter lens with no great problem. I don't remember using anything but 7" and 8" lenses on mine long ago. However, some correction was required to make illumination even. One way to do this is to take a sheet of glass to rest on top of the diffusion glass, and abrade the center with valve grinding compound. An easier solution is to use translucent paper or perhaps a ground glass and darken the center with a pencil.

 

[ic-racer]

Your bulb may be showing through the diffusion plate. Is it the original one that is more dense in the middle?

Did you see this thread? There are some interesting ideas on making Elwood enlargers have a more even light source.

 

[ic-racer]

Also, from the manual, do you have yours set up this way:

The 3 pieces of clear glass are placed in the recess in side the body of the enlarger and above the negative carrier, and the sandblasted glass is placed on top.

With the S-2 Studio Enlarger the size bulb is 2 7/8" in diameter. Do not use a smaller bulb. There would be a dark ring show on the projected field which would be caused by the dark space between the bulb and the silvered part of the reflector.

 

[rjmeyer314]

I have a 5x7 Elwood that I use fairly often. I have it set up with a 131mm Repromaster lens. I don't have any hotspot problems whether I'm enlarging 4x5 or 5x7 (yes, the lens will cover 5x7). I suspect your problem is the height of the bulb above the negative. There is an adjustment for this (at least there always has been on the 2 different 5x7 Elwoods I've owned, and also on my 8x10 Elwood). If you look at the neck on the diffusion dome you will see the screws that hold the light bulb holder in place. (Take out the bulb before messing with this, Elwood bulbs are too hard to find to chance breaking one.) If you remove the screws holding the bulb holder in place and remove if from the neck you will see that there are several sets of screw holes so that the bulb holder can be set to different vertical positions. If you try different bulb positions you should find one that eliminates your hot spot.

 

[rjmeyer314]

Further thoughts: The diffusion dome is a parabolic reflector. You want the light bulb at the focus of the parabola. Then the light once reflected from the reflector will come out in rays parallel to the axis of the reflector, giving even illumination to the ground glass above the gegative. If the bulb isn't at the focus, the rays will tend to spread (giving a colt spot at the ground glass center) or converge (giving a hot spot at the ground glass center).

 

[coisasdavida]

darken the center with a pencil.

Great idea!

 

[coisasdavida]

Also, from the manual, do you have yours set up this way:

ic-racer, yes, I do own the original diffuser.
maybe it is not sitting on top of three sheets of glass. I'll check.
And I'll the bulb diameter too!
thanks a lot.
later I found the manual at cameraeccentric! great!

 

[coisasdavida]

I have a 5x7 Elwood that I use fairly often. I have it set up with a 131mm Repromaster lens. I don't have any hotspot problems whether I'm enlarging 4x5 or 5x7 (yes, the lens will cover 5x7). I suspect your problem is the height of the bulb above the negative. There is an adjustment for this (at least there always has been on the 2 different 5x7 Elwoods I've owned, and also on my 8x10 Elwood). If you look at the neck on the diffusion dome you will see the screws that hold the light bulb holder in place. (Take out the bulb before messing with this, Elwood bulbs are too hard to find to chance breaking one.) If you remove the screws holding the bulb holder in place and remove if from the neck you will see that there are several sets of screw holes so that the bulb holder can be set to different vertical positions. If you try different bulb positions you should find one that eliminates your hot spot.

rjmeyer,
I did a quick search on the repromaster, but all links point to you. hahahaha.
You wouldn't happen to have a spare 131mm?
I didn't know there was this hidden setting. I'll look into it and report back! Thanks!

 

[coisasdavida]

ic-racer, yes, I do own the original diffuser.
maybe it is not sitting on top of three sheets of glass. I'll check.
And I'll the bulb diameter too!
thanks a lot.
later I found the manual at cameraeccentric! great!

Had a chance to go back to the lab and take notes:

original diffuser - check
stack of glass - check
bulb diameter - 3 1/4"

 

[coisasdavida]

If you try different bulb positions you should find one that eliminates your hot spot.

rjmeyer, I appreciate how polite you were.
Now I know that you were probably thinking: how come this guy can't see those height adjustment screws???

Well, there was photographer in Exeter, Ontario, Canada, called John Doerr. At some point in his life he had some adhesive tape made up containing his name, probably to seal envelopes containing proofs and so on. For some reason, one day he decided to wrap lots of this specific tape around the head of his Elwood enlarger. I don't know how this enlarger made its way to Kitchener, Ontario, Canada, but it did. Then one day the other photographer that owned it left it in the curb for me to find. I still remember debating wether or not I should remove that tape one day, but I left it there. I came back to Brazil and 10 years later that tape is still there, but will be removed today.