Omega D5-XL, corners dark on 4x5

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tim.bowman
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Omega D5-XL, corners dark on 4x5

Post by tim.bowman » Wed Feb 21, 2018 6:41 am

I have acquired a lovely, late-model D5-XL with the condenser lamphouse.

I'm using it with a 135mm lens, but finding that on 4x5, the corners are about a half stop darker than the center with the moveable condenser in the recommended top position. When I remove the condenser entirely things get better, but the corners are still about a quarter stop darker. I'm measuring reflected light from a piece of blank paper on the baseboard with a Gossen Luna Pro. There is no negative in the holder during my test.

I'd really like to have even illumination across the entire negative.

Am I missing something, or do I expect too much perfection from a machine meant to do everything? Should I just learn to burn the corners to compensate?

Thanks in advance for your tips.

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sanchell
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Re: Omega D5-XL, corners dark on 4x5

Post by sanchell » Wed Apr 25, 2018 3:23 pm

Greetings, Tim. I have been using the D5-XL for more years than I can recount. I have owned several. It's not the best enlarger ever made but it's my personal favorite. I have not experienced the corner fall-off that you have. What tests have you run? For example, take a reading without the condenser or lens in place. Then add the lens. Then add the condenser. Perhaps it is the lens? Perhaps you have an imperfect condenser? If so, I'll look to see if I have a spare and send it to you to try. Let me know.
Do it in the Dark,

Steve Anchell

tim.bowman
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Joined: Mon Nov 07, 2016 8:55 am
Location: Winston-Salem, NC, USA
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Re: Omega D5-XL, corners dark on 4x5

Post by tim.bowman » Fri Jun 22, 2018 5:38 am

Thank you for your vote of confidence in the D5-XL, Mr. Anchell. I had a long and productive relationship in the 90's with a D2, and this machine is even better.

I can't fit my meter up into the bellows, so I made reflectance readings off of a sheet of white paper on the baseboard. I did manage to reduce the falloff to 1/4 stop by removing the variable part of the condenser.

Maybe I should have another look at my lens. Could be it's not covering quite enough.

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sanchell
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Re: Omega D5-XL, corners dark on 4x5

Post by sanchell » Fri Jun 22, 2018 7:23 am

The lens is a real possibility. I learned early in my darkroom career that all enlarger lenses are not equal. What lenses are you using and for which formats?
Do it in the Dark,

Steve Anchell

tim.bowman
Posts: 27
Joined: Mon Nov 07, 2016 8:55 am
Location: Winston-Salem, NC, USA
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Re: Omega D5-XL, corners dark on 4x5

Post by tim.bowman » Mon Jun 25, 2018 7:02 am

I think I may have figured out my problem this weekend.

I'm using a Kodak Ektanon 135mm f:4.5 lens. Not super new and fancy, but serviceable.

I had been printing a paper negative on 11"x14" paper. Exposure times were getting ridiculous, so I opened up the aperture the whole way. Now that I've had a peek up through the lens with a mirror on the baseboard, I can see that this lens doesn't cover 4x5 negative wide open.

Once I stop it down, I'm okay.

Thank you for your troubleshooting help!

Best,

-t
Last edited by tim.bowman on Tue Jun 26, 2018 3:51 pm, edited 2 times in total.

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sanchell
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Re: Omega D5-XL, corners dark on 4x5

Post by sanchell » Mon Jun 25, 2018 9:59 am

9 times out of 10 the solution is simple - not enough lens coverage or your batteries went dead!
Do it in the Dark,

Steve Anchell

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