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Ilford Multigrade 500 on a Beseler 45mxt- Problems with exposure

Daniel Kim , May 12, 2004; 07:49 a.m.

I have recently bought and have been messing around with the ilford multigrade 500 system. I have found one bothersome fact and am not sure if this is normal or abnormal. First off I am using two rodenstock lenses. One is of 50mm length and the other is 80mm. Now this bothersome fact applies too both lenses either or. My school uses the beseler 45mxt setup and my teacher told me that depending on the size of the negative the upper bellows have to be extended at a certain length. She said the bellows should be extended at least 6 inches if the negative is 35mm. 4 1/2 inches if the negative is 2 1/4 and 1 inch if the negative is 4x5. Currently I'm using 35mm negatives and I set the upper bellows to 6 inches on the 50mm lens and find that the exposure light is vingetted a bit. The outer edges are lightly exposed and the light is concentrated in the center. As I close down the f-stop on the lens. I can see a rectangle of light concentrated in the center and the edges are weak. So when I print, my image is crisp anc clear in the center but the edges are barely exposed. The only way to fix this I found was to make the upper bellows 1 inch. With the upper bellows at 1 inch the exposure light seems evenly illuminated and as I stop down The light is evenly diminished. Unlike the upper bellows at 6 inches. I was wondering if this is normal or SHould I always print with the upper bellows at 1 inch extension. THank you. I need HELP ASAP.


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ann clancy , May 12, 2004; 09:45 a.m.

Is the school using the same light head? We have the 400 and the bellows remain in what would be the 4 x 5 stage. The 400 also has mixing chambers that must be changed out, perhaps the 500 does the same with a change in negative size and lens size.

With a condensor head the negative stage bellows must be moved for proper coverage of specific negatives. With cold light, diffusion heads and color heads the negative stage is placed at the 4 x5 postion. Try closing the bellows down all the way , check the mixing chambers. If you are getting even illumination with the bellows at 1 inch continue to use that setting.

Daniel Kim , May 12, 2004; 10:36 a.m.

Yes the 500 is a variable contrast diffusion head. And comes with 3 mixing chambers. One is for 35mm, others are for 2 1/4, and 4x5. I am currently using the 35mm mixing chamber in conjuntion with the head. So you are telling me since that the head is diffusion type. I should use a 35mm mixing chamber but have the upper bellows always at the 4x5 1 inch setting? The heads at our school are all condensor types except the color lab. Maybe that is where the difference lies. Thanks

Daniel Kim , May 12, 2004; 10:41 a.m.

the bellows at our school differ from mine in that the upper bellows are in the form of a square coming straight down. And the focusing bellow is a square that gets smaller like and upside down pyramid. The one in my darkroom is square and both bellows are the same size. Do you think this is the contributing factor? So for everything I print with the bellows at one inch? What is the purpose of the upper bellows then?

Robert Davis , May 12, 2004; 10:48 a.m.

Beseler's cone of light focuses the light onto the negative. With 4x5 you need a larger piece of light so the negative is kept closer to the condensors. With 35mm OTOH you don't want to waste that light. So you move negative further away. This saves all the mess of having to change condensors with format change.

Draw a triangle. The condensor end is the open end of the triangle. The bigger the negative the closer the negative needs to be to the condensors.

I think that's right.

ann clancy , May 12, 2004; 11:50 a.m.

With the enlargers at your school lab it is necessary to move the negative stage to correspond with the correct size, Just place your negative stage at the 4 x5 stage. Changing the mixing chambers effects coverage and time. If you use the 2 1/4 mixing chamber it will certainly cover the 35mm negative; but your times will increase. It can be done so that you are not always changing mixing chambers but just remember the down size is increase in expousing times, The 35mm mixing chamber will not cover larger negatives, so it is important to switch to the large box.

ann clancy , May 12, 2004; 11:54 a.m.

Forgot to answer your question about the upper bellows. THey are important if you change light heads; i.e. condensor type. THen you would use that upper bellows to adjust for negative size. With enlargers that have a condensor head there is a small measuring device that indicates the proper position for the bellows vs negative size. This is what your insturctor is doing with giving the inch measurements for negative sizes. Perhaps those devices are no longer on the enlargers at school or you havn't noticed. Regardless, with a condensor head that bellows must be moved with relationship to negative size. Smaller the negative, the further the light source from the negative, larger the negative, the closer.

rob . , May 12, 2004; 11:58 a.m.

Daniel, I have an Ilford MG500 head on a Beseler 45 enlarger. Coincedentally, I also use both 50mm and 80mm lenses (Rodenstock) for 35mm and medium format negatives, respectively. I havent' expereinced the problems you seem to be having. I always have left the bellows all the way up, and have never had a need or desire to move it. The person I bought the equipment from said that's what they did for everything from 35mm to 4x5, and it also works for me. I enlarge 35mm, 6x6, and 6x7 negs and keep the medium format mixing chamber always installed (6x9 is the size, I think) as well. I really like the results, ease of use, and the flexabilty I get with this enlarger.

William Whitaker , May 12, 2004; 02:25 p.m.

You don't still have a condenser lens installed somewhere in the system, do you? On a Beseler I don't know how that would be possible, but your description of a rectangle of light, bright in the center is suggestive. Perhaps it's just that your enlarging lens stopped down is beginning to bring into focus the light source.

For best results, a diffusion head such as the Ilford 500 should be mounted such that the diffuser (the light source) is immediately above the negative.

Alexis Neel , May 12, 2004; 04:09 p.m.

The Ilford 400, 500 and 600 Multigrade light systems are designed (no matter what enlarger) to rest/attach to the top part of metal above the negative stage and are not to be adjusted to a further height. The bellows should also be compressed, with no further extension. All 3 systems have at least 3 mixing chambers, 35mm, 6x6 and 4x5. These are to be changed when changing a negative to the approperiate size, although a 4x5 can be used for anything smaller than 4x5, and the 6x6 can be used for anything smaller than 6x6. (Using a larger diffuser for a smaller negative will decrease your contrast about 1/2 a grade though). With Condensor and some color heads, the upper bellows needs to be adjusted for the particular negative.



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