Vignetting on the print

[thefizz]

So this has me puzzled. A print I was making today was very vignetted and I can’t work out why.

The negative was a 6x7 (slightly cropped) and the lens was a 90mm (set 2 stops down) which I have used for years. The enlarger is a Kaiser VPM7005 which has a multigrade head.

The lens ring was the correct type for 60mm to 105mm lenses and was inserted correctly and the enlarger was very well aligned.

There is no vignetting on the negative itself.

I put the same neg and lens in a different enlarger and no vignette to be seen.

Any suggestions of what else I should check on the Kaiser?

 

[pentaxuser]

So if you project the negative onto white paper what vignetting, if any, do you see? I cannot work out how a projected negative with no vignetting on it can cause vignetting that you did not see when focusing the negative and still not see when you switched the enlarger on to expose your paper?

I'd try using the back of the vignetted print you made to see what you see. If there is any obstruction then it has to show up at that point and gives you something to try to eliminate on the Kaiser

I have blades for cropping on my Durst negative carrier and it is possible to accidentally touch slightly and give a shadow effect on the paper. It depends on how you define vignetting but my definition is blocking light from the negative stage in all the corners giving that classic "old days" oval effect on the print

pentaxuser

 

[MARTIE]

It's not an enlarger I'm familiar with so I had a quick look online.
Which double condensers is the enlarger fitted with? (You'll need to take the head off in order to check)
35mm, upto 6x6, upto 6x9?

 

[thefizz]

My model goes up to 6x7. I’m going to take the double condenser out and see if anything looks off.

I should clarify when I said vignetting on the print, I was referring to the corners being lighter to the rest of the image, like a significant light fall-off, so maybe vignette is the wrong word in this instance.

 

[Don_ih]

maybe vignette is the wrong word

It's the right word. Condenser, lens, or light bulb placement is about all that can cause it. Probably not the negative (it would be very weird for a negative to have more density in the corners than in the centre, unless that was what you photographed).

 

[Taurabon]

If the problem hasn't suddenly started with your enlarger, it may be that the condenser lens was replaced with one that is not compatible with 6x7 (e.g. up to 6x6).
Or you may be able to improve the situation by moving the lamp back and forth.

 

[MARTIE]

The most obvious cause would be trying to print a 6x7 negative with the 6x6 condenser.
Therefore, a quick check should clarify it.

 

[Ian C]

When vignetting occurs, the usual problem with a condenser lens set is that the projected light is concentrated into too narrow of a beam for the intended negative size.

A condenser assembly projects light in a fixed converging beam that’s intended to concentrate the light into a uniformly illuminated circle not much larger than the diagonal of the format for which it’s intended. In this respect, a condenser set behaves very much like a magnifying hand glass.

For vignetting caused by the condenser set to happen, either the coverage angle is too narrow—wrong condenser set for the format—or the distance from the condensers to the negative is too close.

I don’t know the design of the Kaiser enlarger. The Beseler 23C, CII, and CIII use a variable-position light source and condenser set mounted into a single unit that is raised or lowered relative to the negative so that the converging beam is concentrated to cover the diagonals of the negative. To aid in the placement, Beseler has included a format scale and indicator on the right side of the upper unit.

I have found that it can project a vignetted ring about the corners like the description in post #1, even when the indicator is positioned correctly. In the case of the 23C series enlargers the final position of the upper unit is best checked as follows:

1. With the lens installed, compose, and roughly focus the image of a negative.

2. Remove the negative and leave the carrier in position.

3. Carefully observe the projected light that falls upon an upside-down scrap sheet. The projected light should be of uniform intensity.

4. If any vignetting is seen, disregard the format indicator and adjust the position of the upper unit until the vignette disappears and the illumination is uniform, Replace the negative into the carrier, focus, and you’re ready to print.

https://cameramanuals.org/topcon/beseler_23cii-pr.pdf

http://www.jollinger.com/photo/cam-coll/manuals/enlargers/beseler/Beseler_23C_II.pdf

Regarding the Kaiser enlarger, it seems that either the wrong condenser set is installed, or it’s not properly positioned relative to the negative.

 

[koraks]

A print I was making today was very vignetted and I can’t work out why.

Dark or light corners?

 

[thefizz]

Dark or light corners?

Light

 

[koraks]

Did you print on a larger size than you usually do?

 

[thefizz]

I’ve been using this enlarger for fifteen years or more, never had this problem before. I checked the condenser and it’s clean and in the correct position.

 

[thefizz]

Did you print on a larger size than you usually do?

Nope

 

[Pegajoy]

Sorry for stepping in. I come from the IT side and I am always analyze problems very structured. You tell anything on the enlarger side is the same as usual and works with all other negatives sice xx years. On the other side, the negative doesn't show any vignetting. That means it is either a wonder and you should contact the pope, or something is not like you tell - surely by accident. Hopefully you will find it - best wishes. Difficult to help you remotely. From my experience, normally the enlarging lens or the lightning box or condensers are not fittng.

 

[Pegajoy]

I had the same problem after buying a Meopta Meograde enlarging head for my Maginifax 4 6x9 enlarger. There was a 6x7 diffusor lightning box attached. I thought it was for 6x9 cause there is nothing in the whole internet that it ever exists or was produced - just 6x9, 6x6 an da 135 versions. Took a long time to find it out...

 

[pentaxuser]

I had the same problem after buying a Meopta Meograde enlarging head for my Maginifax 4 6x9 enlarger. There was a 6x7 diffusor lightning box attached. I thought it was for 6x9 cause there is nothing in the whole internet that it ever exists or was produced - just 6x9, 6x6 an da 135 versions. Took a long time to find it out...

I can see the sense in what you say but the OP declares he has been using the enlarger for 15 years without this happening before What has to be true is that something has changed in the enlarger set-up that the OP is unaware of

If the condenser set-up is correct for 6x7 negatives then as has been said something within the condenser set-up has altered to cause this effect

the fizz, can I ask if the lightening in each corner of the print is of the same intensity and when you focus on a white piece of paper the negative nothing shows up ie in the corners of that paper

Sorry if the answer is yes and you didn't answer it because the answer is Yes , obviously there is a darkening in the corners of the negative You would be right that this is the obvious answer that there is a darkening in the corners but we are getting to the stage of "clutching at straws" to arrive at an answer or so it seems to me

Thanks

pentaxuser

 

[Pegajoy]

Just trying to help... Good luck..

 

[Ian C]

In paragraph 3 of post #8 I erroneously used “too close.” I had edited this to the correct “too far.” I thought that I had saved the change, but apparently not. When I tried to re-edit, the time limit to edit the post had expired. The edit-time limit used to be something like 24 hours, but for some reason this has been significantly shortened.

The correct information is:

If the distance from the condensers to the negative is too far, then the fixed angle converging cone of light will not fully cover the format. That would account for the vignetting as described. So too would the use of the wrong condenser set.

Whether that or some other problem is causing the vignetting is unknown. I suppose that something might be intruding into the light path. But that seems unlikely assuming that it presents as a circular darkening of the periphery of the projected light.

If a masking-blade negative carrier had been in use and the blades were left partially closed, that could account for vignetting. But since the originator of the post is well-experienced, this not likely.

 

[MARTIE]

Just for clarity.

1. The condenser in your enlarger is the 4449 as in the picture I posted?

2. You've printed 6x7 negatives in this exact same set up for the last 15 years and this is a new phenomenon?

 

[GregY]

"light fall-off".......

 

[koraks]

I’ve been using this enlarger for fifteen years or more, never had this problem before. I checked the condenser and it’s clean and in the correct position.

It's really odd, that's for sure.

What's the last time you successfully printed this size negative at this magnification without vignetting? What have you altered about the enlarger since that session?

 

[pentaxuser]

Just trying to help... Good luck..

No need to say sorry. Your contribution was helpful. We are all struggling to find an answer

pentaxuser

 

[Pegajoy]

I would propose to inspect the negative deeper. Normally, I never digitalise anything, because I hate it and I work tho whole day on a computer. But for a preview and in case of your's it would make sense. Rating a negative is always difficult if you are not a professional and do it frequently, I also fail on it always. Did you tried it with a tool like the Kodak app that doesn't' change anything except of the brightness?

 

[MattKing]

Check the focusing bellows for deformation into the light path.

 

[Taurabon]

I was looking at pictures on ebay for information on the Kaiser VPM7005. Since you say you use that enlarger regularly, I'm assuming there was no unintended someone's modification.
If the condenser lens unit setup is just a drop-in to the enlarger chassis, isn't it upside down?
(Sorry if that's a rude question, I just want to help you get back to normal darkroom work quickly.)
I hope it gets resolved.