10 x 8 darkroom query
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Leon West
- Posts: 15
- Joined: Mon Aug 07, 2006 10:12 am Etc/GMT-1+01:00
- Location: Cardiff, South Wales.
10 x 8 darkroom query
Hey everyone, just a few enquiries. Is there any members that enlarge 10 x 8? I have a Devere 5108, and a metoform 24" dry to dry RA4 processor. I'm using a 300mm lens on the enlarger, and I'm having a few teething problems. Mainly focusing when I enlarge. My negative carrier has only one sheet of glass in it, so I assume it's a combination of negative 'popping' and / or misalignment of the head. I found that if I use two sheets of glass in the carrier, when I dropped the light down after inserting the negative, sometime I would end up cracking the glass. This is obviously due to the head being misaligned? Has anyone had unsatisfactory results with enlarging 10x8? Maybe I need an alternative lens? The head is quite high, and the bellows extended quite a bit, just to get a 12x16 enlargement. And even then I can see a slight diffused look over the entire print. Obviously, the contacts are crisp and sharp, but as soon as I try and get enlargements, I tend to lose the clarity. Anyone had simular teething problems? How did you remedy them? What other focal length enlarging lenses will cover 10x8 comfortably? Hope all of this makes some sort of sense, any feedback / ideas welcome.
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Apple
- Forum Hero
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- Joined: Sun Apr 23, 2006 7:04 pm Etc/GMT-1+01:00
- Location: West Yorkshire
Leon,
A few points for the enlarger - you don't need to alter the position of the bulb for each time you put a negative in - it's a one-off setup then it should be fine. The height needs adjusting so that you get an even spread of light across the full baseboard (do this without a negative in the carrier.) You can try it by eye or even use some paper and develop them all at the same time to see if the tones are consistent from the centre to the edge of the baseboard. You're effectively focusing the bulb by adjusting the height.
For the negative carrier, I should expect two sheets of glass are a must for 10x8 to keep the neg from sagging under it's own weight and popping under the heat - if you've been cracking the glass when dropping the bulb down then you're either physically hitting it (not designed to do this) or you're getting too much heat into it and shattering it (a potential fire risk etc.)
Is it a condenser enlarger or diffuser? If condenser, are these the correct ones and mounted in the correct configuration. I have a model 54 DeVere (predecessor to the 504) and it's possible to have different condenser combinations depending upon the focal length of the enlarging lens. Is the bulb the correct rating for the enlarger? Too high a wattage will run hotter which can lead to problems.
A quick calculation in my head seems to think that 300mm is about right for 10x8. I'm guessing it is an enlarging lens you are using rather than a camera lens...?
For head misalignment, you're most likely to see that when you make a print - it could be sharper at one end of the print than the other. It's possible to get round this a bit by stopping down on the lens but it's only a workaround / bodge - it's better having things true.
Andrew
A few points for the enlarger - you don't need to alter the position of the bulb for each time you put a negative in - it's a one-off setup then it should be fine. The height needs adjusting so that you get an even spread of light across the full baseboard (do this without a negative in the carrier.) You can try it by eye or even use some paper and develop them all at the same time to see if the tones are consistent from the centre to the edge of the baseboard. You're effectively focusing the bulb by adjusting the height.
For the negative carrier, I should expect two sheets of glass are a must for 10x8 to keep the neg from sagging under it's own weight and popping under the heat - if you've been cracking the glass when dropping the bulb down then you're either physically hitting it (not designed to do this) or you're getting too much heat into it and shattering it (a potential fire risk etc.)
Is it a condenser enlarger or diffuser? If condenser, are these the correct ones and mounted in the correct configuration. I have a model 54 DeVere (predecessor to the 504) and it's possible to have different condenser combinations depending upon the focal length of the enlarging lens. Is the bulb the correct rating for the enlarger? Too high a wattage will run hotter which can lead to problems.
A quick calculation in my head seems to think that 300mm is about right for 10x8. I'm guessing it is an enlarging lens you are using rather than a camera lens...?
For head misalignment, you're most likely to see that when you make a print - it could be sharper at one end of the print than the other. It's possible to get round this a bit by stopping down on the lens but it's only a workaround / bodge - it's better having things true.
Andrew
Full Member of the Tearoom Appreciation Society - affiliated to UKLFPG.
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Richard Kelham
- Posts: 30
- Joined: Wed Aug 16, 2006 10:40 am Etc/GMT-1+01:00
- Location: north Norfolk
It's a good while since I used a 10x8 enlarger but no matter. I used a Kamm with a cold cathode head rather than a condenser head, but the principles are the same.
Yes 300mm is the correct focal length for an enlarging lens – ideally one computed for up to say 4-5x enlargement – though you could use a 240-270mm if it gave enough coverage.
Negative holder should have 2 sheets of glass to keep the film flat. I also used to stick a whole 35mm film in the carrier for really impressive "contact sheets".
If the glass gets broken by the lamp then you are clearly doing something very wrong! Apart from anything else there should be a pair of bloody great condensers in between. Do you have the right ones? Have you focussed the light source properly? Alternatively get a new head for it, one with a cathomag light source perhaps (they take up less room and give better light).
I hope you have a very high ceiling. Even below the neg stage you're looking at 20" or so of bellows for an average sized print. Even with the baseboard near the floor you'll need a good 10 feet of headroom, more for comfort, which is why many/most enlargers for 10x8 and above are horizontal rather than vertical.
It's a great machine: I hope you sort o ut your problems.
Richard
Yes 300mm is the correct focal length for an enlarging lens – ideally one computed for up to say 4-5x enlargement – though you could use a 240-270mm if it gave enough coverage.
Negative holder should have 2 sheets of glass to keep the film flat. I also used to stick a whole 35mm film in the carrier for really impressive "contact sheets".
If the glass gets broken by the lamp then you are clearly doing something very wrong! Apart from anything else there should be a pair of bloody great condensers in between. Do you have the right ones? Have you focussed the light source properly? Alternatively get a new head for it, one with a cathomag light source perhaps (they take up less room and give better light).
I hope you have a very high ceiling. Even below the neg stage you're looking at 20" or so of bellows for an average sized print. Even with the baseboard near the floor you'll need a good 10 feet of headroom, more for comfort, which is why many/most enlargers for 10x8 and above are horizontal rather than vertical.
It's a great machine: I hope you sort o ut your problems.
Richard
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Leon West
- Posts: 15
- Joined: Mon Aug 07, 2006 10:12 am Etc/GMT-1+01:00
- Location: Cardiff, South Wales.
Andrew & Richard,
Thanks for the reply and advice. I have been away, hence my delay in responding! I managed to rectify the problem with the enlarger head, it now lifts perfectly, with both the head and lens parts rising and falling completely parallel and straight. So what enlarger problems I had seem to be resolved. I have also changed the lens from a 300mm Rodenstock to a 240mm Schnieder, which does the trick a treat. It allows the enlarger head to be a lot closer, and meaning I can dial in the filtration a lot easier. I am still getting problems with the print sharpness. I get a good focus with my focus finder, but when I get an enlargement of 16x20, you can definitely see it isn't as sharp as you would expect. The contacts I make from the neagtives are seriously sharp, but as soon as I enlarge, I lose quality. I have a dry to dry processor that allows me to enlarge upto 24x30, it would be a shame to use the equipment I have to merely contact print. I assumed it was a problem with the De Vere 5108, maybe the fact that I am using a diffuser head? I posted a few topics sometime back with regards to exposing images, I use the Schneider lens at f90 to take the picture, and someone mentioned you don't get sharp images at such tiny apertures - this maybe the case here? I remember getting massively confused by the whole circle of confusion issue, and with my Schneider 240mm taking lens, the maximum aperture on the dial is f45, even though it goes two stops beyond that. Hmmm, teething problems. I just want super sharp prints, I have a few Eliot Porter prints, and I understand he used a 4x5 camera, and they are super sharp! I don't understand why images I take on a negative size four times bigger, look decidedly unsharp.
Thanks for the reply and advice. I have been away, hence my delay in responding! I managed to rectify the problem with the enlarger head, it now lifts perfectly, with both the head and lens parts rising and falling completely parallel and straight. So what enlarger problems I had seem to be resolved. I have also changed the lens from a 300mm Rodenstock to a 240mm Schnieder, which does the trick a treat. It allows the enlarger head to be a lot closer, and meaning I can dial in the filtration a lot easier. I am still getting problems with the print sharpness. I get a good focus with my focus finder, but when I get an enlargement of 16x20, you can definitely see it isn't as sharp as you would expect. The contacts I make from the neagtives are seriously sharp, but as soon as I enlarge, I lose quality. I have a dry to dry processor that allows me to enlarge upto 24x30, it would be a shame to use the equipment I have to merely contact print. I assumed it was a problem with the De Vere 5108, maybe the fact that I am using a diffuser head? I posted a few topics sometime back with regards to exposing images, I use the Schneider lens at f90 to take the picture, and someone mentioned you don't get sharp images at such tiny apertures - this maybe the case here? I remember getting massively confused by the whole circle of confusion issue, and with my Schneider 240mm taking lens, the maximum aperture on the dial is f45, even though it goes two stops beyond that. Hmmm, teething problems. I just want super sharp prints, I have a few Eliot Porter prints, and I understand he used a 4x5 camera, and they are super sharp! I don't understand why images I take on a negative size four times bigger, look decidedly unsharp.
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Richard Kelham
- Posts: 30
- Joined: Wed Aug 16, 2006 10:40 am Etc/GMT-1+01:00
- Location: north Norfolk
Yikes! f90! Yes I would say you are indeed getting into serious diffraction problems. Try not go below f32, or f45 at a pinch (yes I know Weston et al called themselves the f64 group, but...).
If the enlargement is properly focused the grain should be sharp even if the image isn't. Assuming you can find some grain.
Good luck.
Richard
If the enlargement is properly focused the grain should be sharp even if the image isn't. Assuming you can find some grain.
Good luck.
Richard
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Apple
- Forum Hero
- Posts: 361
- Joined: Sun Apr 23, 2006 7:04 pm Etc/GMT-1+01:00
- Location: West Yorkshire
That's some serious aperture you're using 
As well as the diffraction issues (for both taking and enlarging lenses) what kind of exposure times are you getting under the enlarger - must be about a fortnight each
If the contact prints are acceptably sharp and the enlarged ones aren't, the small apertures could be forcing you into loooooong exposure times and then vibration could be rearing it's head - maybe from ventilation fans or generally from the environment (main road nearby, wobbly floorboard, or even if the enlarger isn't fastened down as well as you thought.) I'd heard of someone trying to take 10x+ micro shots and had to turn off the fridge downstairs as the motor set up a vibration through the house...
The DeVere should be built like a tank (mine seems to be) but if you're not having top and bottom glasses on the neg, can you be sure that the neg isn't moving / popping or just distorting under the heat / gravity?
As I understand it, diffraction gives you halos / reduced contrast whereas camera shake (and presumably, enlarger shake) will give you multiple images with a slight offset between unless the image is continually moving during the exposure.
Andrew
As well as the diffraction issues (for both taking and enlarging lenses) what kind of exposure times are you getting under the enlarger - must be about a fortnight each
If the contact prints are acceptably sharp and the enlarged ones aren't, the small apertures could be forcing you into loooooong exposure times and then vibration could be rearing it's head - maybe from ventilation fans or generally from the environment (main road nearby, wobbly floorboard, or even if the enlarger isn't fastened down as well as you thought.) I'd heard of someone trying to take 10x+ micro shots and had to turn off the fridge downstairs as the motor set up a vibration through the house...
The DeVere should be built like a tank (mine seems to be) but if you're not having top and bottom glasses on the neg, can you be sure that the neg isn't moving / popping or just distorting under the heat / gravity?
As I understand it, diffraction gives you halos / reduced contrast whereas camera shake (and presumably, enlarger shake) will give you multiple images with a slight offset between unless the image is continually moving during the exposure.
Andrew
Full Member of the Tearoom Appreciation Society - affiliated to UKLFPG.
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Alex Tymków
- Posts: 1
- Joined: Tue Jun 19, 2007 4:19 pm Etc/GMT-1+01:00
Hi Leon
The glass you need to keep the negatives flat should be; an anti newton rings sheet which is mounted above the neg, and a plain sheet blow. The glasses made for the enlarger have bevelled edges so they sit in the neg carrier correctly. If you put the anti-newton ring glass below the neg it may cause softening of your image. The glass is slightly frosted.
hope this is of use
Alex
The glass you need to keep the negatives flat should be; an anti newton rings sheet which is mounted above the neg, and a plain sheet blow. The glasses made for the enlarger have bevelled edges so they sit in the neg carrier correctly. If you put the anti-newton ring glass below the neg it may cause softening of your image. The glass is slightly frosted.
hope this is of use
Alex