Inadequate 5x7 Zone VI enlargers

[scott_mcalpine]

Why does the series one Zone VI enlarger fade out on the ends? The negative under the lightsource has

some room to spare on the ends. If there were a bigger VC coldlite head that would fit would that solve

the problem? I haven't called aristo yet but a new head seems more economical than starting all over with

a 5x7 Durst. Has anyone out there made a Series One Zone VI enlarger illuminate a 5x7 negative properly?

Thank you, Scott.

[mona_chrome]

What lens are you using?? One problem I have heard of is just using too short a lens. I have

friends that used a 135mm for 4x5 and had fall off and switched to a 150mm and it went

away. Sometimes it is just the angle of view of the shorter lens losing the sweet spot of the

light source.

[andrew_oneill]

Lens focal length can be a factor as well as the distance from the light source to the negative. It is best to have the light source as close as possible to the negative.

[tito sobrinho]

I have the same enlarger bought just after F.Picker's announcement.

 

Never had any problems with "fade out on the ends". However for the 4x5 format, I use a 150mm Componon-S enlarging lens, and for the 5x7 format, the 210mm Componon-S.

 

Do you have the 5x7 carrier?

[tito sobrinho]

What I meant was: Do you have the proper Series one 5x7 negative carrier?

[richard_ritter]

Is it the VC head or the single buld? The head may have been put together wrong.

[pico_digoliardi]

Scott: I waited to send this response so that I could talk to a colleague who has that very enlarger he bought new. I remember he had trouble with it right away. We had lunch just this afternoon and he said that Yes, the 5x7 enlarger he got had a head designed for 4x5 - it did not cover 5x7 properly. He went around and around with Fred Picker, and even had a face-to-face with negatives and Picker just stonewalled.

 

It was entirely inadequate for 5x7. My friend completely rebuilt the upper end with different components, some hand-made. Now it works, and he still uses it regularly.

[scott_mcalpine]

Thanks everyone for your quick responses. I'm using the first Series One Zone VI enlarger

with the variable contrast (two tube) head. I enlarge to 16x20 and 20x24 using a 210

Componon-s. The neg. carriers are 5x7 and 6x17cm both series one. I've taken the head off

but not taken it apart to see the actual tubes. It appears evenly lit. When I had the head off I

noticed that the opening on the chassis just below where the neg. carrier rest is exactly 5x7

in. while the effective light source area is about 6x8 in. The light fall off at the ends may be

do to chassis size opening more than head size. Any more ideas, I'll take apart head to look

at tubes next then maybe think a rebuild/modification if neccessary. Thanks, Scott

[scott_mcalpine]

A quick secondary thought about neg. carriers. Titi Carlos Maria Sobrinho ask if I am using

the proper series one 5x7 neg. carrier. I had it and the 6x17cm. made from other series one

carriers to fit the 5/7 & 6/17 format. I'll have another look at those.

[tito sobrinho]

Scott, sorry for your trouble.

 

I've been using the series one for a long time. Originally, I bough the series one 6x9cm, 4x5" and the 5x7" carriers.

The latter, never gave me any problems, i.e. enlarging my 5x7" negatives with the 210 Componon S, to 16x20" with uniform illumination across the board.

 

Later on, I called Calumet in order to buy the 35mm, and the 6x6cm carriers. The series two enlarger was out and they asked me specifically if the carriers were for the one; or the two series. I got the series one carriers and I've been happy ever since.

[paulwainwrightphotography]

A few years ago I had a dialog with Richard Newman at Calumet about the fall-off problem with the original Zone VI VC enlarger, and didn't get much sympathy. I use it for 4x5 with a 180 mm lens, and I was still seeing a lot of fall-off. I re-built the diffuser in the head by doing the following: first, I removed the original diffuser (it's 2 sheets of milk white plexi, separated by about 1/4 inch, and located quite close to the negative). I added a sheet of drafting velum just under the tubes, and then added a new sheet of thicker milk white plexi located further away from the negative (about an inch as I recall). I also added mirrors to all 4 sides of the inside of the head between the 2 diffusers. The mirrirs tend to illuminate the plexi more evenly. Although not perfect, it's much better. I still do some edge burning to compensate.

[scott_mcalpine]

Thanks for the answers. I'll look at diffusers after modifying the way the two VC tubes are

held into place inside the housing. The inner housing of my head already has mirror/silver

type reflectors. It my be a later improvement from the original. Thanks again, Scott McAlpine

[scott_mcalpine2]

Hi photo.net readers. I thought I would update this question (about even illumination for the 5x7 format; Zone VI series I enlarger with a

210 Sch. lens. After all your great responses I had it working to perfection soon after all your suggestions. Here's what I ultimately did.

 

I unscrewed the plastic milky white diffusion sheet from my VC head. Chipped away plastic white bracing bars AND extraneous rubbery

glue holding the two flourescent tubes within the housing. I left only essential white plastic brace to hold the flourescent (sp.) tubes. I

hope that make sense. The aim and result was eliminating any obstruction of the direct light path to the diffusion sheet. It was effective

for my head in evening out the light fall off at the ends of the 5x7 format. Falloff still exist but it is the normal amount due to the distance

of the head to easel. I.E there is naturally more fall of at the edges than at the center do to the inverse square law. I hope this helps

anyone with the same circumstances as it took help from the community for me to figure out. "Nuff said."