Building a light source

[RoBBo]

I shoot a good deal of 11x14.
I want to be able to enlarge them traditionally.
I may be able to get a hold of a partially pieced Elwood 8x10.
How difficult/possible would it be to put some extra space between the lens and where the source (currently missing) ought to be and stick a homebrew diffusion source on it?
Just fluorescent tubes in a 14x16 box over some diffusion paper?
Would that cover/manage? What do I have to do to ensure even light?
The more simple I can make it the better, but I'm not looking to cut any corners.
Might be able to get a POS 11x14 off ebay instead of the Elwood if that'd be easier.
More concerned about the source right now though.

 

[resummerfield]

I’ve been thinking about, and working on something similar to enlarge 7x17 on my Durst L1840. That’s about the same diagonal as 11x14, but I can not fit the 11x14 to my enlarger due to the Durst focusing standards being too close to the lens axis. For 11x14, an enlarger like the DeVere which attaches the focus mechanism to the column would work better.

I’ve made a “prototype” in which I space the 7x17 negative from the existing Durst negative stage with a 22” long x 12” deep by 12” high box made from ½-inch Baltic birch plywood. My neg carrier is a simple 2-piece glass sandwich, resting on rails attached to this box and aligned to the lens. It’s not very satisfactory, as I must remove the light source to change the negative.

I’ve conducted some basic tests using a single row of 24-inch fluorescent tubes, packed as tightly as possible in another plywood box, with an acrylic diffuser about an inch above the neg. This worked, but I need better diffusion—I’m guessing another, secondary diffuser an inch or so above the first. This will require raising the lamps which will further diminish the intensity, so I plan to line the light box with reflectors or aluminum foil, and add another row of lamps to increase the light output. I’ve also been considering the higher-intensity 3w white LEDs available for under-cabinet kitchen lighting, although they will produce more heat.

I’m using a 360mm El Nikkor lens, but this requires high ceilings for a vertical enlarger—I have 12-foot ceilings. With the head fully up, I can enlarge about 2.5x with the baseboard in the normal position, and I calculate about 3.5x with the baseboard fully down. Another, probably better, option is a 260-270mm wide-field process lens, which would require less headroom.

When (or if) I get everything worked out, I’ll replace the plywood with aluminum, and build a better negative carrier that I can remove independent of the light source.

So far, I’ve found contact printing much easier for the 7x17 negs. But as you have found, it would be nice to enlarge certain negatives. The easiest, and probably the best solution, would be to find an 11x14 working enlarger. But the only working ones I’ve seen (Jens Jensen in Hillsboro, OR) are still very expensive.

 

[dslater]

Ansel Adam's book "The Print" has a brief description of his cold light source - probably not enough information to justify buying the book, but your local library has a copy, it might be worth a few minutes to read the relevant chapter.

Dan

 

[mustard seed]

I’m also going to build an 11x14 enlarger. I have been shooting 4x5 and 8x10 for along time and have done away with the 8x10, almost done with the 11x14 camera. I have bought an old nuarc process camera with a jml 81/4” lens. The camera is in almost new condition, but I don’t think this lens will cover the 11x14. I plan to take off the vacuum back and build a light source using the new Florence screw in bulbs. Any suggestions on a lens that will cover this format?

 

[Nicholas Lindan]

I’m also going to build an 11x14 enlarger. I have bought an old nuarc process camera with a jml 81/4” lens

If it is a horizontal camera, and you put it on rails, it should make a good ULF enlarger. If the camera isn't on rails then the maximum print size will be the size of the copy board (minus an inch or so).

The model number gives the size of the media it can take: a VV1418 will take 14"x18", usually the size of the vacuum back. Range is 1:3 to 3:1.

nuArc is still around, though they no longer make cameras. Most of the customer support personnel have been around since the time of the flood and so they should be able to answer questions about the camera.

The lens's are usually wide angle on the compact cameras. The 8 1/4 should have 90 degree coverage, if I do my maths right. JML is still in business, you might see if their web site has any info.

With 90degree coverage it should cover a 16.5" diagonal at 1:infinity. 11x14 is an 18" diagonal. At moderate enlargement ratios it should cover 11x14.

The camera may not have enough bellows draw to use a 'standard' lens.

 

[resummerfield]

.....Any suggestions on a lens that will cover this format?

A 480mm Apo-Nikkor should cover 11x14.

 

[mustard seed]

Thanks for the help
I had planned on building the 11x14 camera to do contact prints. When the nuarc came along. It was bought by the university in 1980 and was used by one person the whole time until I picked it up. It came with the manual and a whole bunch of other stuff. I was called to take a look at the thing by a friend that works in that department. I paid $200 for the thing; I thought what the heck why not enlarge the 11x14. I have about a 1000 square ft in my darkroom and work room so I’m going to give it a go.

Thanks again for the help.

 

[dancqu]

Just fluorescent tubes in a 14x16 box over some diffusion paper?

In the early 60s I had and worked with a 4x5 fluorescent. It had
four or five tubes and no diffuser that I recall. Likely an Omega.

Pencil thin tubes are available at least to one foot. Color
balance is something to keep in mind. Like Graded? Dan

 

[ic-racer]

I know this thread is a little old, however, I came across a NuArc camera that may be very reasonably priced. I saw it in the same shop when I picked up my 8x10 Durst enlarger last week (http://www.largeformatphotography.info/forum/showpost.php?p=316515&postcount=3). Looks like the Durst and the NuArc were all that were left. I was originally looking for a process camera for converson to an enlarger, but since I was there actually buying an enlarger, I didn't pay that much attention to the NuArc. I recall it had a Goerz lens but I don't recall the format size of the camera. Perhaps 11x14.

Here is the link to the folks that sold me the Durst. (this was posted over in the LF forum) http://www.largeformatphotography.info/forum/showthread.php?t=32367

They don't mention the NuArc in the ad but, from what I can recall, he said it was also for sale.

Again, I'm not the one selling it, I just saw it sitting there and thought someone in the APUG community might be interested.

If someone winds up getting this camera let me know with PM as I have some of the NuArc manuals in with my Durst literature folder.