Prints partially underexposed

[mindcircus]

Hello, I have a Meopta opemus 6 enlarger with an El-Nikkor 50mm f2.8. The problem is that in all my photos, the right side is quite underexposed, not only the photo, but the film frame too. I can't figure out what's the cause; the lens is clean, and so are the film and the filter drawers. Any ideas what's wrong?

Thanks in advance, Stelios

 

[ic-racer]

The negative is lighter on one side, right?

How was the film processed?
Which side is light?
Camera?
Horizontal Focal Plane Shutter?
Shutter speed used?
Flash, yes,no?

 

[hugopoon]

Read about someone else with this problem just a few hours ago…someone suggested checking the alignment of the bulb/lamp.

Do you have a negative that you've printed well in the past that you could test with?

 

[RalphLambrecht]

Hello, I have a Meopta opemus 6 enlarger with an El-Nikkor 50mm f2.8. The problem is that in all my photos, the right side is quite underexposed, not only the photo, but the film frame too. I can't figure out what's the cause; the lens is clean, and so are the film and the filter drawers. Any ideas what's wrong?

Thanks in advance, Stelios

You say all your photos, so, I assume it's not your negative.

Has this happened recently, or was it always like this?

 

[Ian Grant]

I'd guess the lamp needs adjusting if it's the condenser version of the enlarge, there should be some way of adjusting it. This is a common problem with this type of enlargers.

If it's the colour head check that the light-box and lamp are seated correctly.

Ian

 

[John Koehrer]

The problem is that in all my photos, the right side is quite underexposed, not only the photo, but the film frame too.
Thanks in advance, Stelios

If the film is unevenly exposed it's in the camera and there's nothing you can do to correct it in printing. Well there may be if you feel like burning or dodging a lot.
One of the shutter curtains is slow & requires some adjustment. Nothing major but not usually user correctable.

 

[R gould]

If it on the negatives as well as the prints then the problem lies with the camera,I guess you are using a SLR with a focal plane shutter that one of the shutter curtains is running slowly, I can't see there being a problem with the meopta opemus 6, I have one myself and have used it for several years without problem,there is no adjustment you can make to the lamp, it is a fixed position, I would get the camera shutter checked,it should not be too big a job,Richard

 

[Michael Erb]

When I was in high school we had an Omega enlarger that was giving us very poor exposure on diagonal corners. It turned out that the lamp head assembly had jumped off of the track slightly and the lens was not parallel to the base any more. When we got the thing back on the column properly our exposure problems went away.

 

[mindcircus]

Well, sorry if I haven't explained the problem well...
I said my prints are underexposed, not my negatives. I have printed many negatives, from different cameras (it's not capping for those who wonder) and I 've tried different paper sizes.
I have the same problem in most prints, that is the right side of the paper does not get the same amount of light that does the left side. I've found a few prints that do not have this problem, but I guess it was the position of the negative in the negative carrier...
Now, I've opened the head and I see that the condenser and the bulb position are fixed, so it doesn't seem to be misalignment between them. The only thing that might be a problem is that the bulb was a common one, not for use in enlargers. I changed it with another common one to see the differences but I do not have the time to test it today.

Thanks for your interest everyone, I'll try to come back tomorrow with the results of my tests...

 

[RalphLambrecht]

...Now, I've opened the head and I see that the condenser and the bulb position are fixed, so it doesn't seem to be misalignment between them. The only thing that might be a problem is that the bulb was a common one, not for use in enlargers. I changed it with another common one to see the differences...

Are you using frosted bulbs without labeling?

 

[mindcircus]

I bought it second hand and the bulb that was on it (until yesterday) was a frosted one with the label next to the screw (100W). Now I've put a (150W) frosted one with the label on the worst position; the bottom of the bulb. I'm just trying to exclude misalignment between condenser and bulb at the moment.

 

[RalphLambrecht]

I bought it second hand and the bulb that was on it (until yesterday) was a frosted one with the label next to the screw (100W). Now I've put a (150W) frosted one with the label on the worst position; the bottom of the bulb. I'm just trying to exclude misalignment between condenser and bulb at the moment.

Please report on the progress, and I'm sure, we'll figure out a solution.

 

[Ian Grant]

Enlarger bulbs are generally not frosted, instead they are white powder coated on the inside, like fluorescent tubes, this gives far more even lighting.

Ian

 

[MartinP]

Ordinary household bulbs have imprecisely made/mounted elements and thin 'opal' colouring. It would be lucky indeed if one worked well in a condenser enlarger as the condenser focuses the light (and whatever irregularities there are in the bulb) to go through the neg. carrier. The photocrescenta enlarger bulbs are more expensive than normal for a reason, unfortunately.

BTW, the coating on the inside of fluorescent tubes is the bit that makes the light (it fluoresces when zapped by the otherwise non-visible e.m. radiation produced by the gas in the tube) - other than the superficial colour there is nothing in common with an enlarger bulb. Indeed, compact fluorescents don't work well in enlargers because of their discontinuous light spectrum, as well as the start-up time of course.

 

[Ian Grant]

What's common is they are coated internally rather than frosted glass

Yes you're right I tried a normal household bulb in a Durst once in an emergency and it's pretty much impossible to get even lighting.

I think there were also some thicker white opaque glass enlarger bulbs at one time, but these enlarger lamps are no longer made by the major manufacturers and are quite specialist now hence the higher costs.

Ian

Ordinary household bulbs have imprecisely made/mounted elements and thin 'opal' colouring. It would be lucky indeed if one worked well in a condenser enlarger as the condenser focuses the light (and whatever irregularities there are in the bulb) to go through the neg. carrier. The photocrescenta enlarger bulbs are more expensive than normal for a reason, unfortunately.

BTW, the coating on the inside of fluorescent tubes is the bit that makes the light (it fluoresces when zapped by the otherwise non-visible e.m. radiation produced by the gas in the tube) - other than the superficial colour there is nothing in common with an enlarger bulb. Indeed, compact fluorescents don't work well in enlargers because of their discontinuous light spectrum, as well as the start-up time of course.

 

[RalphLambrecht]

Ordinary household bulbs have imprecisely made/mounted elements and thin 'opal' colouring. It would be lucky indeed if one worked well in a condenser enlarger as the condenser focuses the light (and whatever irregularities there are in the bulb) to go through the neg. carrier. The photocrescenta enlarger bulbs are more expensive than normal for a reason, unfortunately...

There is no doubt that enlargers bulbs are the way to go, but in a pinch, a regular frosted bulb will work well enough. To improve light distribution, I added a thin milky sheet of plastic film on top of the condensor once, and it worked really well as a condensor/diffuser hybrid.

 

[Anon Ymous]

Mindcircus, assuming that you live in Athens, you can still buy a proper enlarger bulb locally. IIRC, Geramas has 150W bulbs for less than 10€. time to stock up I suppose...

 

[mindcircus]

Actually I live in Patras and there is no place here to find enlarger bulb. That's why I tried an ordinary one. If that's the cause I'll buy a few when I go to Athens.

I'm surprised though that I didn't find anybody having the same problem. I mean I've read about people having developed film in horse's urine... Is it so crazy to put an ordinary bulb in an enlarger? Do you think Ι need a psychologist to see me?

 

[RalphLambrecht]

...Is it so crazy to put an ordinary bulb in an enlarger? Do you think Ι need a psychologist to see me?

No, it works in a pinch. See my post above.

 

[Anon Ymous]

No, it works in a pinch. See my post above.

Which makes me wonder if putting something like "milky plexiglass" in the filter drawer would give good results.

 

[Ian Grant]

Often enlargers that used an ordinary bulb have a diffuser between the bulb & condensers. I have an early Gnome enlarger that uses a clear 12volt bulb the type used in vehicles and that then has a ground glass diffuser 2cmm above the condenser.

You can paint light bulbs. People used to paint bulbs red as safelights years ago and it's still done for decorative purposes, so there's no raeson why with the right paint a standard bulb couldn't be painted white for enlarger use.

Google "painting light bulbs"

Ian

 

[mindcircus]

Just one more thing... I don't think that the coating is the most important parameter here. It's probably the shape and the size that play a major role in light uniformity. As far as I can see the enlarger bulbs have the shape of sphere unlike ordinary household ones that have many asymmetries in their shape. If it was the colour/coating and the label, I think that the milky glass in the filters' drawer and a milky glass above condenser are enough to alleviate such heterogeneities in light density.The shape though gives light beams different directions.

Just a thought...

 

[mindcircus]

Meopta Opemus 6 has two milky glasses: one in the drawer for contrast filters and one above that. They are not too hazy, but they should diffuse light. I don't think that adding one more would make any difference...

 

[RalphLambrecht]

Which makes me wonder if putting something like "milky plexiglass" in the filter drawer would give good results.

Yes, but probably loses too much light. I used a frosted plastic foil.

 

[mindcircus]

I used a frosted plastic foil.

Isn't that dangerous with the heat of to bulb? The condenser is quite close to the bulb