Elwood 5X7 Enlarger diffuser - Help Please

I just bought a model SP-25 (I think) 5X7 Elwood Enlarger in pretty good shape but it is missing a part(s). In the parts list (it came with a parts list brochure!) its called a "light filter and heat absorbing glass". This fits in the bottom of the light housing over the negative stage and I think it diffuses the light. Without this glass in place the light is very uneven. Is there some special pattern to this glass? Could I have one made from heat resistant frosted glass and would that work? Is this enlarger a worthwhile project or should I not waste my time? It seems pretty sturdy and was cheap. I would appreciate any tips from anyone with experience with these machines.

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.

 

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Regards,

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.

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!

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

There's a 5x7 piece of Kodak Opal glass on eBay this morning. Bill

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!

Thanks for all the good suggestions!

I've found this source for opal glass in a variety of sizes.

<a

href=http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1671> http://www.edmundoptics.com/IOD/DisplayProduct.cfm?Productid=1671</a>

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.

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!!

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

I've been experimenting with this Elwood now for a couple of days and at this point I wonder what is even illumination on the baseboard? I've tried pieces of ground glass, sandblasted a center filter effect on clear glass and a white diffusion glass. The white glass alone seems best so far. Its still a bit hot in the middle - about .5 to .7 stops brighter than the corners. This over an area roughly equal to a 16X20 using a 4X5 negative. It seems to fall off quite a bit more in the far reaches - it won't cover 5X7 evenly. So what -is- even enough illumination? I'm starting to think that an Aristo cold light head is the real answer. Or a different enlarger. Comments please.

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.

 

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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.

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!

I have a 5x7 Elwood also. Where do youall get replacement lightbulbs?

 

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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...

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

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.

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.

Yesterday I was trying to print with my elwood. I had installed a

large bulb, some 200W thing.

It was hot spotting too much. If I removed the lens board and

looked up, I could see the lamp through the elwood frosted

glass.

After much trying, I finally decided to see if the dome was clean

inside, it had a bit of dust and I reached in to clean, my surprise

was to see my whole hand reflected inside the dome and not the

enlarging lamp.

I figured the lamp had to be lower inside the dome to be

reflected, this 312 bulb must have been pretty long bulb then.

I attached a extension to the socket, that one you find in the

hardware store, with two eletric outlets and a second socket,

which gave me another 2 inches os "bulb length".

That was it, finally the dome was doing his part, I could see the

lamp through the ground glass, and I got an extra couple stops

of light on my baseboard.

It doesn't hot spot at all!

Amazing how the solution was simple.

 

Regards,

Gui

São Paulo, Brasil.

www.coisasdavida.com