View Full Version : Elwood 5X7 Enlarger diffuser - Help Please

Henry Ambrose
20-Feb-2002, 20:30
I just bought a model SP-25 (I think) 5X7 Elwood Enlarger in pretty good shape b ut it is missing a part(s). In the parts list (it came with a parts list brochu re!) its called a "light filter and heat absorbing glass". This fits in the bott om of the light housing over the negative stage and I think it diffuses the ligh t. Without this glass in place the light is very uneven. Is there some special p attern to this glass? Could I have one made from heat resistant frosted glass an d would that work? Is this enlarger a worthwhile project or should I not waste m y time? It seems pretty sturdy and was cheap. I would appreciate any tips from a nyone with experience with these machines.

Doug Paramore
20-Feb-2002, 20:39
Henry: The old Elwood is a good enlarger. I owned one years ago. The glass was ground or etched more in the middle, and tapered off toward the edges to even out the light. I don't know how to describe it enough for you to make another one...it will take a little experimenting. You might check with Midwest Photo Exchange. They carry a lot of hard to find stuff. They have a web site.


Brett Thomas
20-Feb-2002, 20:58
Henry, I bought a Elwood 5x7 enlarger last year. In shipping the enlarger the frosted glass broke and my attempts to glue it back together again were unsuccessfull. What I ended up doing was buying a round piece of opal glass and placed that at the bottom of the dome, right above the negative carrier. I also purchased a cold light head from Aristo that is specifically made for the old Elwoods. I still have it but the opal glass seems to provide more even illumination than the cold light head. Try the opal glass, it should correct the un-even light. The Elwood is a big piece of equipment, but for the price, it works just fine.

John Kasaian
20-Feb-2002, 21:38
Henry, The old Elwooods are fine enlargers and worth the effort. My 8x10 lost it's opal disk on it's cosmic journey to my darkroom, and as far as I can tell they are darn near impossible to find. Flat opal glass is still being made, I think Stephan Shuart has some. It would be worth checking. I recall one of the stores at the Photomall.com has opal glass too. I suppose the shorter the glass has to travel the less chance it has of breaking in route, but thats just a guess. By the way, you'll want flashed opal glass, not the kind sold at stained glass suppliers which has a random marbled pattern. Additionally, some Elwoods had a center filter or provision for one(mine does) Four posts stick up to hold a square piece of glass above the negative carrier. You can make your own by cutting the glass to fit, taping one side, cutting a circle and removeing the tape in the circle and grinding the exposed glass thats unprotected by the tape. Use carbide grit. Remove the rest of the tape and viola! A center filter! Not precision engineering but hey, it works on Elwoods! I read somewhere that the closer the diffusion glass is to the negative, the better the results. If this is so, you might try putting a piece of 5x7 flashed opal glass as part of your negative sandwich, if you have a negative holder that will permit it which would be cheaper than having a circle cut. In addition, you'll probably need a piece of anti-newton glass to place against your negative in the carrier as well. I think Stephan Shuart has this, and I've seen 8x10 and 11x14 sheets on Ebay on occasion that you could cut down. I think I paid about twenty bucks for an 8x10. As far as heat goes, they do get HOT. So far I haven't had any problems, though I suppose you could use your Elwood to warm your lunch just don't try to make grilled cheese sandwiches. Melted cheese is difficult to remove from Elwoods. Photgraphic Systems sometimes has parts for Elwoods. Good Luck!

Greg Nelson
20-Feb-2002, 23:28
Henry: I agree that Elwoods can be pretty good old enlargers, and have many satisfactory prints to prove it. I was faced with your same problem at the start. The previous owner had 4 plates of frosted glass in the iron piece above the negative holder, at the base of the reflective dome. Without a graduated, center-weighted diffuser, however, prints were impossibly "hot" in the center. I made my own using a 5x7 plate of glass and a spray can of white Rustoleum paint. It sounds extremely unscientific and surely won't meet the psychological needs of the perfectionist -- but I have yet to find fault in it: Shake the can well and give a few practice sprays to make sure the spray is "fine." Prop the 5x7 plate about 10 inches or so away and give a couple of short blasts toward the center. It took me 3 tries (different plates) to get one I liked. I then mounted it at the top of the stack of 4 plates in the Elwood, and haven't looked back. Any small scale irregularity in the painted area is lessened by the fact that it is furthest from the negative, and the other plates are frosted. Good Luck

21-Feb-2002, 09:56
There's a 5x7 piece of Kodak Opal glass on eBay this morning. Bill

John Kasaian
21-Feb-2002, 11:51
Henry, I've been looking for a source for flashed opal on the West Coast. www.abrisa.com has both flashed opal and heat resistant stuff. I'm waiting to hear back from them what their minimum orders are and if they'll cut to suite. They have a lighting products department so they might have other suggestions. Might be worth giving them a try also. Good Luck!

Henry Ambrose
21-Feb-2002, 14:31
Thanks for all the good suggestions! I've found this source for opal glass in a variety of sizes. http://w ww.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1671 (http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1671) I wonder about cutting these sheets without damaging the coating. I'm still looking for an original center filter glass for this enlarger before I try to make one. Keep those ideas coming.

C.W. Dean
21-Feb-2002, 23:10
It's a shame that the most fragile (and usually broken or missing) piece on the Elwood contributes so much to it's successful operation. Opalized glass may work fine for others but I dislike the long exposures. The factory center filter is more or less ground glass which blocks the center hot spot and graduates gently out to the edges. Although my Elwood still has the original factory glass in tact, I have seen successful home-made efforts using grinding paste on clear glass. The combination of tungsten lamp house and the center filter gives a diffusion that I find every bit as pleasing as any cold light that I have ever used. About 5 years ago, I installed the clunky Elwood as my primary enlarger and have never felt the need to return to cold light. The prints on VC paper respond especially well to the tungsten diffused light source and I don't think I have ever made better prints. 95% of my prints are sold to customers--so much for the latest in high tech gear!!

John Kasaian
22-Feb-2002, 02:28
FWIW, I have toyed with the idea of switching the bulb in my Elwood to a silver tipped reflector bulb that would reflect the light up into the polished dome. I don't know if this would eliminate the need for a diffussion disc and/or center filter, or if it would be overkill. Maybe someone has experience with these bulbs and would like to share their thoughts?-----John

Henry Ambrose
23-Feb-2002, 22:26
I've been experimenting with this Elwood now for a couple of days and at this po int I wonder what is even illumination on the baseboard? I've tried pieces of gr ound glass, sandblasted a center filter effect on clear glass and a white diffus ion glass. The white glass alone seems best so far. Its still a bit hot in the m iddle - about .5 to .7 stops brighter than the corners. This over an area roughl y equal to a 16X20 using a 4X5 negative. It seems to fall off quite a bit more i n the far reaches - it won't cover 5X7 evenly. So what -is- even enough illumina tion? I'm starting to think that an Aristo cold light head is the real answer. O r a different enlarger. Comments please.

Bob Eskridge
24-Feb-2002, 17:32
My Elwood came with a diffusion glass that looks like it was sandblasted at the center. Unfortunately I haven't gotten the enlarger set up yet and haven't checked the light evenness.

My suggestion is to try your various set ups. You may find that the light fall off matches/complensates for the fall off in your negatives and is little desirable.

John Kasaian
24-Feb-2002, 20:01
Henry, sounds despirate! Here Is a $2.95 experiment. I just picked up a 100 watt Satco Silver Crown bulb I'm going to try in my Elwood. The tip of the bulb is silvered inside and out, so light isn't emitted out of the top(bottom when installed) of the bulb. All the light goes into the reflective dome, which in turn will be reflected off the silvered exterior of the bulb's tip. This should reduce your hotspot. It has a much smaller wattage than I normally use in my 8x10 but it might be closer to the wattage you use in 5x7. Good luck!

Emile J Schwarz
24-Feb-2002, 22:37
I have a 5x7 Elwood also. Where do youall get replacement lightbulbs?

On hotspots... Has any tried raising or lowering the light in their condencer. I saw an article years ago on adjusting the focus of the domed condencer by adjusting the light source placement.... just a thought...

John Kasaian
25-Feb-2002, 02:09
Beau, There is an enlarger lamp list at The Darkroom Guy at Photomall.com that says what lamp goes with which enlarger---even Elwoods---if you can't find your lamp locally I'd give The Darkroom Guy, Terry Seaman, a try......John

Jim Hutchison
5-May-2002, 17:56
Hi all, This might sound rediculuos, but I think it will work. I have a 5x7 enlarger (not sure of brand), but I am having the same peoblem with uneven light. The first thing I did was get one of those light bulbs with the reflective tip. Didn't get much better. Then I thought about diffusion material. I thought...maybe fabric softener??? After 3 pieces, (between the ground glass and a clear piece of glass), the light looks very even. I won't be testing this until tomorrow and I am not sure if the fabric will get too hot, but at this point anything is worth a shot.

Al Kaplan
27-May-2002, 20:49
I used an Elwood in the early 1960's. My dad had bought it back in '36 or '37. It was equipped with a BIG enlarging bulb, #311 or #312 if memory serves, with a mogul base. My dad had it fitted with a single opal glass diffuser. It did hot-spot a bit, but nothing you couldn't correct with a bit of dodging.

Guilherme Maranh?o
8-Jun-2002, 15:10
I just got one Elwood Pattern Works enlarger last week. A guy here in Kitchener, Ontario, was getting rid of a bunch of stuff in his darkroom, and I stopped by to see what he had. It came for free, as long as I took it away! It's a 5x7, can't really tell which model, I have no reference.

It had 4 pieces of rectangular glass on top of the negative stage: one frosted ("center-weighted frosting") and 3 plain ones. I just finished cleaning the whole thing and replacing the lens that came with it by one I had already. I placed a piece of acrylic sheet (from the garbage bin behind a plastics shop) in the place of all that glass. Haven't tried on paper, but looks nice and even. I'll keep my eyes on the effects of the heat on the acrylic piece.

Good luck to you all, Take care, Gui

Bob Shimmon
28-Jun-2002, 16:37
I found that by purchasing one of those "add a socket" bulb extention adapters from the local hardware store for about $1.99 and inserting it between the bulb (I used a enlarger bulb from adorama)and the lamp socket, I was able to get the correct extention to bring the bulb into good focus so there were no hot spots at all. You will find that there are extra sets of screw holes to allow more extention of the socket for the extra adjustment needed.

Emmett W. Francois
3-Jul-2002, 22:21
I will be in the process of trying to get an Elwood 5x7 enlarger up over the Summer. I need to know what the dimentions are for the negative carrier. The enlarger did not have one and I will also have to replace the light socket and bulb. It looks like the answer for the bulb is to replace the socket, add the extention and use a standard 4x5 enlarger bulb. Any photos of the negative carrier would be appreciated.

Al Kaplan
22-Jul-2002, 16:33
The originsl carrier for this was the same as used in the Burke & James Solar 5x7 enlarger. It's made of wood, probably 12 to 15 inches long, and has a 5x7 inch rectangular hole in it with a narrow ridge running around the inside about 1/4 inch thick, and 2 sheets of glass. There's also a "finger cut out" at each end of the hole so you can lift out the two pieces of 5x7 glass. The negative is sandwiched between the glass sheets. This gives you no less than six surfaces to get the dost off of, but the negative is FLAT! Burke and James marketed a set of glassless negative carriers, really 5x7 pairs of aluminum sheet metal, that you could use instead of the glass, in all sizes, including a bunch for totally obsolete roll film sizes (118, 116, 122, 828, etc.) and metric sizes like 6 1/2x 9 cm, 9x12 cm, 13x18 cm. If you have tool freak friends you could convert a piece of 3/4 inch plywood into the basic carrier frame and use 1/8 inch aluminum for the inserts. Otherwise, cobble together a carrier out of scrap wood and 2 pieces of glass. Or just have your local glass shop cut you a couple pieces of glass long enough to push through without wood, probably about 6x12". Good luck!

Paul Rogers
27-Feb-2005, 15:09
Hello my name is Paul Rogers and Elwood Rogers was my uncle. I worked for him at his plant in Indianapolis in the 50's. The glass you are asking about was made by placing the glass on a turn table under a sand blaster as the glass turned it was blasted from the center out. The sand blast head spent more time in the center and less time on the outter portion. My uncle was a great guy and designed and built a very rugged enlarger./

Good luck
Paul Rogers

todd curry
18-Nov-2010, 06:18
Hi paul rogers, I would like to talk with you about your uncle Elwood Rogers, I believe I bought his Mansion and would like to ask you some questions about his life. 317-374-7132

19-Nov-2010, 14:50
I have two Elwoods, a 5x7 and an 8x10. I like and use both. I've been lucky that my two have made several moves without the ground glass breaking. If it did break, the problem wouldn't be replacing the ground glass, which you can buy at any glass shop. The problem is really to get the transmission profile of the glass right from the center to the edges and corners. One of my enlargers (I think the 5x7) has a ground glass that looks dirty. I haven't cleaned it because it gives prints that are well balanced, center to edge. I think what's been done is that the etched side of the glass has been mounted pointing up, smooth side down. Then a light graphite dusting has been put on the rough (up) side. I think by playing with the amount of "black" put on the ground glass you can tailor it's transmission coefficient to eliminate the bright spot in the center. If you make a mistake, wash it off, let it dry, and start over. A densitometer would help, first to measure the density profile of a print from the clean diffusion glass, and second to profile the optical density of the diffusion glass/graphite to get the graphite dusting right. Or you can just do it by trial and error.

John Moye
16-Oct-2012, 05:40
Has anyone ever seen glassless negative carriers for the 5X7 Elwood enlarger? At an estate sale this past weekend. I found a 5X7 glassless negative carrier, model #NC-2, serial #687 It has the name "The Kriser Corp" engraved on it. I am trying to use it with the 8X10 Beseler cold light head, which is mounted on a 4X5 Beseler enlarger. I can be reached at moye44@aol.com