who has or can describe an Elwood 8x10 diffuser?

Discussion in 'Darkroom Equipment' started by Murray@uptowngallery, Jul 14, 2008.

  1. Murray@uptowngallery

    Murray@uptowngallery Member

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    Hi:

    I am wondering who among the 8x10 Elwood enlarger users here still has the glass diffusion plate in the lamp head, and can confirm my feeling it's placement would be closest to the negative stage. I also suspect the ones that used sheets of ordinary glass for heat absorption placed it above the diffuser.

    If you REALLY want to be helpful, a photo or your best description of the approximate diameter of the most heavily blasted/ground region of the diffuser would give me an idea what it looked like (how Elwood accomplished a solution). I've read the Elwood 1929 patent, but think they made a variety of reflectors over the years (parabolic, elliptical and one other, I forgot). They may have made changes over the years too...

    I just picked one up. I may try a sheet of opal glass above the negative stage, but am not opposed to trying my own grinding. I have equipment that would allow me to objectively measure luminance on the projection surface, and a densitometer. I know Jim Jones here just stacked sheets of hand ground glass until he was satisfied with the uniformity of illumination he could achieve.

    Thanks

    Murray
     
  2. raucousimages

    raucousimages Member

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    I got mine without the glass. I had opal glass cut to fit and it has worked well. I have never had heat glass in it but I found a second dome and I am converting it to accept a hose to a ventelation fan to suck out the heat.
     
  3. Jim Noel

    Jim Noel Member

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    Originally the heat absorbing glass laid on the top of the opal diffusion glass. This package rests on the metal ring immediately above the negative carrier.
     
  4. Murray@uptowngallery

    Murray@uptowngallery Member

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    OK, I wonder if Jim's opal glass was an Elwood evolution or a field mod...interesting. I was aware of the sandblasted gradient diffuser (by reputation only).

    Jim & Rauc, do you use opal or frosted lamps?

    Mine came with a 500W opal #302 lamp. I have a box of 300W extended life PS35 lamps, but they are internal frost, not opal.

    I may have two different situations to check out given the big difference in the two lamps.

    Thanks

    Murray
     
  5. colrehogan

    colrehogan Member

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    Mine is buried in the shed outside until we move to a place in which I have a chance of setting up a darkroom. Although the lens and at least the light bulb are inside our current home.
     
  6. PHOTOTONE

    PHOTOTONE Member

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    While Opal glass will work, it will dramatically reduce the light output. The gradiated sandblasted glass, thick in the middle, tapering off towards the outside is optimum. Heat absorbing glass always closest to the light source, to keep heat away from negative.
     
  7. ChuckP

    ChuckP Subscriber

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    Mine didn't come with any of the glass pieces. To add to the confusion the drawings in my Elwood parts list show the sand blasted glass located on top of the 3 heat absorbing glass pieces. Glass is shown as 12x12 in. This is for the commercial C-2 model not early wooden ones. As far as bulbs go they recommend 300(150w) or 301(300w) but say that a 302(400w) can be used.
     
  8. Murray@uptowngallery

    Murray@uptowngallery Member

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    Thanks.

    Speaking of construction differences...ChuckP, can you tell which 8x10 model or vintage mine is from a description?

    Has 2-piece cast iron hinged vertical part with a 3-hole mounting pattern. The lower half of the lamp head I would guess is a different cast metal because it is not terribly heavy. At the rear of the lamp head is what looks like mahogany. The reflector looks to be parabolic and a hammertone green or khaki (? it's very dirty, hard to be sure). One handwheel for head height and a smaller handwheel for bellows adjustment. Has a 500W opal 302, which could be much newer than the enlarger, so that's not a useful clue.

    Rauc-Im: I had a thought about directing heat to a negative dryer, but realized that would only be useful for drying negs at exactly the time the enlarger is running...pretty random chance of that...
     
  9. richard ide

    richard ide Member

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    Murray,
    I had an Elwood similar to what you describe. The diffuser was a stack of 12 sheets of window glass. Very light frosting on the bottom one. The reflector is parabolic and about 22" high without going in the basement and measuring. The head was counterbalanced by a cast iron weight which rested on the back of the column. I could also tilt the enlarger for horizontal projection. I just kept the reflector. The previous owner used it for BW and colour. I did not like it that much as I found prints to be too soft compared to other equipment I had.
     
    Last edited by a moderator: Jul 16, 2008
  10. Murray@uptowngallery

    Murray@uptowngallery Member

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    !

    For 3/32 (2.5 mm) glass, that's roughly 17# (7.5 kg) of glass! 22.5#/10.3 kg for 1/8"/3mm glass!

    Looks like they did it many ways over the years, I guess changing when an improvement or deficiency was observed.

    I wonder if results vary with one's lens of choice. I think this tells me the way to get uniform illumination is the method that works for me. Should I make a signature tagline 'the best diffuser is the one that works for you'? (Nah, maybe not).

    Murray
     
  11. ChuckP

    ChuckP Subscriber

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    I put the parts list on my comcast space:

    http://home.comcast.net/~lfuser/Elwood/C2.mht

    Hope that works. That's the only model I know. Nothing about the earlier versions. I believe that part 41 is the only wooden part on mine.
     
  12. Murray@uptowngallery

    Murray@uptowngallery Member

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    Chuck, what's an .mht file extension?

    It doesn't open up very nicely from the link - kind of looks like when someone posts a jpeg image into a listserv mailing list - lots of blocks of unreadable stuff. :O)
     
  13. Phil

    Phil Member

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    Chuck,

    Thanks for the parts list post for the C2.

    I've got an Elwood catalog/price list dated Aug. 1, 1947 (it has 8 enlargers listed and accessories)that I'll get scanned and posted at some point. Your parts list is quite a bit newer based on the prices of the accessories.

    Murray,

    A .mht file is an archive file created by Internet Explorer. The file opened fine for me in IE and I was able to copy and paste it into MS Word.

    See: http://filext.com/file-extension/MHT

    Archived Web Page. When you save a Web page as a Web archive in Internet Explorer, the Web page saves this information in Multipurpose Internet Mail Extension HTML (MHTML) format with a .MHT file extension. All relative links in the Web page are remapped and the embedded content is included in the .MHT file. The absolute references or hyperlinks on the Web page remain unchanged and the .MHT file is viewed using Internet Explorer. Note: This file type can become infected and should be carefully scanned if someone sends you a file with this extension.
     
  14. ChuckP

    ChuckP Subscriber

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    I really don't know what I'm doing. I put the individual pages into a Word file and then used one of the web save as options. If you want I can send you a Word doc file but it's pretty big. PM me an email address if you want it. I have another price list (not parts list) from 1958 that I'll try and scan also. The C2 is listed for $441 for the 48in model and $480 for the 72in model. Dimension is the main slide height. I've never seen a 72in. Need a tall ceiling for that. Pretty expensive for 58.
     
  15. Murray@uptowngallery

    Murray@uptowngallery Member

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    Maybe mht is a IE 7 feature. My day job employer blocked IE 7 installs for a number of reasons so I instinctively avoided doing it at home or my wife's shop either. I have been getting winmail (or whatever it is).dat attachments from someone lately and don't know what to do with them. ".dat" is a reckless file extension for 'winmail' to usurp - there are many other file types that predate it...to me that makes as much sense as thinking it's a great idea to start saving spreadsheets as .exe or .jpg. I have seen too many other .dat files to not comment on a new one.