Question about a Federal 312 enlarger

My Federal 312 enlarger arrived, and it's a real tank! I haven't used it yet as I'm still sorting out lens board issues and figuring out how to mount my 3 lenses, all of which have different size threads. I like it's simplicity compared to my old Durst 606. The Durst was steady, but the glass negative carrier and condenser lens meant lots of print spotting. The Federal can do 6x9 negs too.

The lens boards should be easy to make (unlike the Durst!), from small pieces of wood, but I'm not sure what to do about the cracked opal glass that sits above the diffuser. My question is, do I really need this? It looks like the frosting on it will cause much longer exposures and cut contrast on the prints. I was thinking of simply laying an enlarger filter on top of the glass if I need it for contrast on the prints, but if I don't need the glass, I'll lay them right on the diffuser. It calls for a 75W bulb, but I have a 100W frosted house bulb that I took the printed numbers off w/ alcohol, and thought that might make up for the lack of opal glass.

the glass is to absorb the heat of the bulb, if you are using a 100w bulb rather then the 75w you will need to replace the glass, a glass ought to be able to cut a replacement for you at not much money. d

Hi Momus,
I have a Federal 269 along with its original instruction manual.
That glass is called "a special sandblasted light distribution plate" (Item 46 on the 269)
It sits above the condensor and its purpose is to attenuate the light going down on axis from the 75 Watt 211 Opal lamp, and to increase the brightness of the peripheral light coming down from the reflector.
I have checked the light across the easel using a dslr and it is fairly uniform.

I use a Rodenstock Omergaron1:4.5 90mm for 6x9 and a Rogonar-S 1:2.8 50mm for 35mm
One of these came in a sturdy plastic box that has a 39mm thread to retain the lens in storage.
So I removed the original Federal lens which has a square mount with 4 screws, drilled 4 holes in the plastic box and installed it in place of the lens.

The original neg carrier works fine for 120 film.
To do 35mm, I purchased a cheap neg carrier from another brand and adpted it to slide into the Federal one..

I am not sure how similar my 269 is to your 312 but i can put up some photos if you need.

as the previous statement indicates this is a special glass designed to even out the light over the negative. It is not opal glass. Finding a replacement probably will not be easy. keep the old one and you can do your best to emulate it by hand grinding your own. The hand grinding is simple, emulating that special light dispersion glass is a little more involved.

Thanks very much. I thought about the heat absorption quality of the glass.

You were right wombat2go and Jim, the glass does make a difference. I tried it tonight w/ a 35mm cardboard mask in the neg carrier and it was brighter w/o the glass, but it looked a little brighter in the center. With the glass in (I taped it together for now) it was dimmer, but the illumination looked more even. Oddly enough, I saw no sign of the crack or tape on the baseboard image, probably because the light still got disbursed w/ the diffuser, so I am just going to glue the two pieces together and call it a day. My frosted 100W bulb could be giving a center hot spot too, as it calls for 75W, so I may get a proper 75W enlarger bulb and see how that works. Thanks for the offer on the pics, but these things are so simple there's not much to really go wrong, and there's no adjustments. If nothing is bent, it's aligned.

That was a nifty idea on your lens board. I have a Minolta Rokkor CE X 50 2.8 for 35mm, and a Wollensak Raptor 90 4.5 coming for 6x6 and 6x9. I have a 75 lens for 6x6, but suspect that the 90 Raptor will work. The scheme du jour is to drill out the original lens board for the Minolta, and I have a spare board w/ a 50 4.5 Wollensak that can be hopefully used for the Raptor, assuming that the threads are the same. If they aren't, it gets drilled out and I find a retaining nut for the 90.

I can't believe I found one for sale. Wonder what the odds on this would be?

http://www.ebay.com/itm/Federal-312...623362?hash=item3d17e0f342:g:fmsAAOSwV-RXFN9V

Wow,
Lucky Friday!

Yeah, I had to buy it, and a proper enlarger bulb too. The glass and diffuser was $17.95 and I only paid $20 for the whole enlarger, but that's always the Way of the Enlarger. What starts out costing peanuts quickly gets out of hand, what w/ lenses, negative carriers, bulbs etc.

I usually make my own trays from cut down plastic storage bins, negative carriers from mat board, tongs are my gloved fingers, safelight is a piece of Ruby lith over a night light or an LED bike tail light, thermometer is a $4 Freestyle glass one that I use for film, and the easel is the enlarger base w/ glued cardboard in places for registers. I was using a 135mm camera lens for a grain focuser and that actually worked really well, but I got tired of having to hand hold it on-focus and bought a proper grain focuser on the classifieds here today. Made up some lens boards from wood and mounted each lens in it's own board. Now all I need is the Dektol, fixer, vinegar or citric acid acid for stop, and some 11x14 fiber papers.

I haven't received the new glass yet, but I did try out the enlarger w/ the new 50 2.8 Rokkor lens installed in a homemade lens board, and the image is much dimmer on the baseboard than my old Durst w/ the condenser. Developing the negs for the difference isn't going to happen as I am simply printing up old negatives, so filters filters should help w/ contrast loss. The image doesn't "pop" on the baseboard like I'm used to on condenser enlargers. I'll have to experiment to get this thing optimized.

The "dim" image may turn out to be more contrasty than you think. Prints will tell the tale.