20х24" enlarger

[mamanton]

Thanks, Eric!
Heiland LED system uses Green and Blue LEDs which were precisely chosen from many variants. And the system is calibrated to different modern papers and films. As you know modern multigrade papers are sensitive to green and blue light - that's how we can change the contrast. More sensitive to the blue, a little bit less to the green. The system has a special probe. Firstly you load the film to the negative carrier, focus, close the aperture, choose the name of the paper (for example, Ilford MGIV FB WT), do the measurment on the projection. After that the system shows you a base contrast and exposure, and calculate by itself how much time of green and how much time of blue you need to preserve the details in blacks and show the facturas in whites.
It also has RED LEDs - like safelight - very comfortable option.
All three colours gives you WHITE light for focus.

[Drew Wiley]

I've made plenty of vac easels. They require very little vac draw if intelligently designed. You want small holes distributed in a manner than pull the paper flat in
a predictable manner, not anything like pegboard. You also need internal struts or shims so that the surface isn't deflected on vac draw. Do not use a peristaltic
pump which vibrates due to a diaphragm or piston, but something with a continuous vane effect. Yes, if necessary you can do this with a small true 2-stage HEPA vac in the same room, since these have low decibel levels and will actually clean surrounding air too. But it's important to either have one with variable power or
a bleeder valve to prevent excessive vac draw. Ordinary vacs of shop vacs will need to be isolated in a different room, have a tube through the wall, and then be
equipped with a bleeder. Another problem will be keeping the perimeter of the paper down prior to vac. This can be done with either magnetic bars or a masking
blade system borrowed from a big ordinary easel, or made from scratch. As you already know, some papers have quite a bit or curl to them.

[Monty McCutchen]

Well obviously I've only contact printed my 20 x 24 negs for Platinum/Palladium but when you get this done I'll definitely hire you to make a big print from one of my favorite negatives! That would be great, assuming of course you are open to outside business. Good luck!!!

Monty

[mamanton]

Thanks, Monty!

I hope everything will be done in one year )))

Well obviously I've only contact printed my 20 x 24 negs for Platinum/Palladium but when you get this done I'll definitely hire you to make a big print from one of my favorite negatives! That would be great, assuming of course you are open to outside business. Good luck!!!

Monty

[blindpig]

Once I built a device with a 20X24 lamp house and mounted a glass in front of it.Having the same concern you have about the weight of a removable negative carrier cut a vacuum groove around the edge of the glass and mounted the negative with tape in a piece of estar clear base as a frame allowing the negative itself to become the vacuum blanket. this insured flatness and nothing between the emulsion and lens.In order to gain access to the vacuum glass the bellows would disconnect from the back and move toward the lens temporarily,then close back for projection.This worked well for our needs and eliminated moving a negative carrier in and out of the device.
Like everyone else I'm wishing you all the luck and hope you will share your results.
Don

[mamanton]

Once I built a device with a 20X24 lamp house and mounted a glass in front of it.Having the same concern you have about the weight of a removable negative carrier cut a vacuum groove around the edge of the glass and mounted the negative with tape in a piece of estar clear base as a frame allowing the negative itself to become the vacuum blanket. this insured flatness and nothing between the emulsion and lens.In order to gain access to the vacuum glass the bellows would disconnect from the back and move toward the lens temporarily,then close back for projection.This worked well for our needs and eliminated moving a negative carrier in and out of the device.
Like everyone else I'm wishing you all the luck and hope you will share your results.
Don

Thank you, Don! Very very interesting!

[Drew Wiley]

I once dismantled a huge copy camera where the glass sandwich pivoted on central axis bearings to allow relatively easy film change. A fussy mount to make,
requiring solid precise perimeter support; but that's what machinists are for.

[bob carnie]

Thank you, Don! Very very interesting!

Don is very knowledgeable in these sort of things.

[Andrew O'Neill]

I converted an old copy camera into an enlarger so that I could enlarge my 8x10's up to 20x24. Works very well, with a cold light on top and 240 schneider underneath. Forgive me if this has been answered, but what size enlargements will you be doing?

[mamanton]

Hi everybody!
I'll be on Photokina fair, Cologne, Germany from 23 to 25 September.
I'll be happy to meet somebody of you in real life to discuss the enlarger, and other ULF and largeformat and darkroom equipment.
We can meet each other near the Kienzle booth - Hall 03.1 Stand D 011.
Hope see you soon!