8x10 enlargement problem

[steve barry]

I got the 8x10 durst up and running beautifully. I have been printing 4x5 and 5x7 up until last night when I tried my first 8x10 negative - enlarged to a 30x40 print.

It may be hard to see with cell phone photo, but on the left side of print is about a six inch stripe. I have figured out the smaller stripes on the very edges of the print, had to do with the neg carrier. The diagonal line is a shadow on the print.

But I tried a few negatives, two different neg carriers, different paper, etc. I am thinking it must be something in the head. Any ideas? Is this what a burned out bulb looks like on these by any chance? THANKS

bigger (http://farm8.staticflickr.com/7046/6792153562_2e74623604_o.jpg)

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[vinny]

That wouldn't be caused by a burned out bulb. Looks like something obstructing the light path near the diffusion panel.

[steve barry]

I checked it, but I will check again. It is an omega F color head. Guess I should have said that. Maybe something wrong with diffusion panel itself?

[William Whitaker]

I'm a little confused as to what I'm looking at. I thought at first I was looking at an image on the enlarger easel, but it's a positive image. Or is it a projected image of a transparency? Maybe I shouldn't even be looking at the environmental context...

[steve barry]

haha....I put the dried print back on the enlarging easel to take the photo.

[Andrew O'Neill]

It looks to me as though something is blocking light. Is there any way you can get inside the head? It's almost as if something fell off inside and landed on top of the diffusion plate.

[William Whitaker]

Remove the negative carrier completely to take it out of the equation. See if the problem still exists. It looks like a gross enough issue that you should be able to see it on the baseboard/easel. Otherwise you could meter the baseboard/easel for evenness of illumination.

Since you already tried two different negative carriers, that suggests the head itself. You may have to remove it and open it up. It could be a problem with the mixing box. Judging from the sharpness of the line, it looks to be fairly close to the negative plane.

Unless it's in the negative(s). Have you checked? All negatives from the same box? You're sure none got flashed? Looks like you're using paper from a roll, so probably not that. My 2¢.

[steve barry]

Andrew - yes the head is easy to get at....I will check again for fallen debris. That was my first thought, something fell in transport.

Will - pretty sure its not the negative. I have contact prints made of the negatives that are all good. and the line does not fall in the same place on the negatives. the line is in the same spot on the enlarging easel though, but if I move the negative carrier left/right it reduces/increases the area. if that makes sense. I will try removing the negative carrier all together and try to see it before I do anything. the sharpness of the line - makes sense, it must be close the the diffusion panel.

[bob carnie]

It looks like an internal foam inside the mixing box may be out of place, or an internal masking blade*if your enlarger has this option* is in the way or creeping in.
Also is the easal plane centered to the lens and source light?
This does not look like a reflection from something in the room as that should create a fog line that would be a plus density , it looks like you have an even minus density.... my money is on the mixing chamber having a default

[steve barry]

thanks bob. the masking blades are all the way retracted. easel plane is centered - I mean, its not inches off at least. I will check diffusion panel again and mixing chamber when I get home.

[ic-racer]

You can do a print with the negative out of the carrier to see the defect in illumination better. But I'd probably just open up the mixing box. I'm curious as to what is inside, post a picture.

[steve barry]

I opened everything up and it still seems OK to me?

photo 1 mixing box with camera flash
photo 2 diffuser held up to ceiling light (there is a crack in the upper left corner that someone taped, but would not seem to be causing the problem)
photo 3 looking up with lights off
photo 4 looking up with lights on

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Funny thing is, the problem seems to be gone. When I put everything back together, and turned the light on, I can not see the line anymore. I am going to go make another print now.

[Andrew O'Neill]

It's those pesky gremlins!!

[ic-racer]

Hmm.
How are you processing prints that big? Could that light strip be from under development?

[steve barry]

hey ic, I think you are right. I am roll developing the prints in a tray, which is my first attempt at that. I guess I was just consistently developing the prints enough to reproduce the line - seems unlikely but nothing wrong with mixer/diff - and its gone. not sure, I have to practice I guess. I printed 4 tonight, and this was the best developed....hard line is gone, but there are still some spots, presenting as vertical almost like long inkdots.

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[bob carnie]

Ok so this is making sense now..

How much developer are you using, when I roll big prints I am using over 35 litres of develper. the idea is to fully immerse the roll, and start rolling under chems, this allows even dispersion of chemicals in the first 15-25 seconds of development...

If this sounds like a lot of chemsitry and cost, you must consider the cost of each 30x40 piece of paper being put in the round filing drawer due to uneven development.
I just bite the bullet, save up a days of printing and get on with it.

I use oversize trays, or I use under the bed Home Depot storage containers which hold a ton of chemistry.

[steve barry]

my trays only hold about 3 gallons of chems. They are 30x32 inches. And only about half of the roll is immersed at any given time. So I have been starting by putting half the print completely under and immediately pulling the rest through the developer, then start rolling. I diluted my developer to extended my development time to about 2.5 min. I tried pre wetting the print and putting in developer already rolled but this was the worst of the bunch. I figured I would burn a roll of paper at least getting the hang of this.