20х24" enlarger

[mamanton]

Thanks! Actually that was our idea together with Mr. Juergen Heiland, we wanted to cooperate with Kienzle firstly, but later on most of the things were done only in Heiland electronics company with a big help of Wolfgang, who is a great mechanist from the picture ))
We (Art of Foto company) fund this project by ourselves, this is the enlarger for our own darkroom, but for sure we can also print to other photographers from their negatives.
After the first production I guess Heiland will present the enlarger on his website as an offer for sale (and second one will be cheaper, because we also paid for the project, programming and so on).

That is fantastic. I read through the entire thread again, but still am not sure of a few things. Did you ask Kienzel to make it or did he make it and you are the first customer for a soon to be production unit? Also, will this be your personal enlarger? Did you fund this yourself? Or is this for a group darkroom or a commercial business?

Again, thanks for sharing this fantastic project!

[mamanton]

That's interesting! No rail track! No at all! We have to put the enlarger approximately parallel to the wall, and it calibrates precisely by itself using the 3 lasers, which measures the distance to the wall in 3 points, and the whole enlarge with a lens and negative carrier swings, tilts and shifts to parallel everything!
It looks amazing in a real life, it already works! I will post some pictures or video later on...

And a rail track system?

8X10 is pfft

[mamanton]

Thanks a lot! We already bought Lomo O-2 600mm, and some more lenses, but still we have to test them in a real life.

The LED cold light reduces the heat and power requirement issues... by a factor x10. I use 100w RGB leds, ...cheap

About the lens:

20x24 has a 31" circle, need a 800mm circle. Some enlarging lenses cover around 50º, APO Nikkor 600 covers 37º

Here you have Dan's list of apo nikkors: http://www.galerie-photo.com/apo-pro...ikkors-en.html


> To calculate the needed lens select required circle to cover the negative (the diagonal), then select a focal (450mm or 600mm) and get the covering angle of the lens you consider,

> use plain trigonometry (or solidworks)to know the minimum bellows draw that will cover your circle with the coverage angle you have, for example with 800mm circle and 50º coverage: bellows draw has to be at least 867.8mm, so a 600mm (with 50º coverage) will not focus on a wall that is at very long distance, but as you give bellows draw to focus closer then the circle expands and will cover the 20x24 when the draw is 867.8mm or more:

Attachment 174426

...from the focus formula get the maximum working distance that the minimum bellows draw will allow while covering the negative , here says how: http://www.largeformatphotography.in...=1#post1400399


So it looks that a 450 may cover the 20x24 for "smaller" prints, a 600mm may cover really big godzilla prints and a 900mm would not have limitations.

Anyway if you PM a focal and a coverage angle of a lens you consider I would tell you what maximum enlargement is possible while covering a negative size. Also consider that a shorter focal will end in a greater fall off in the corners, this can also be calculated aprox with the cos^4 rule...


You can start with a LOMO O-2 600mm , I got mine for $50 new (now there are 2 listed in ebay at $200, but offer way less in the case), later you may go to more refined APO nikkor lenses, but if not wanting more than x2 enlargements (this is 50" prints !) just use the O-2, you may not notice anything in the print with a superior lens, at least if not exploring the print with a magnifier.

Regards

[mamanton]

You can easily transform LED module to the table to load/unload a negative to the negative carrier. Plus we can rotate the whole module from portrait to landscape position. Firstly, we thought to create square 24''x24'', but 20x24'' is real cheaper and less weight, which is very important in such a size!





This is a Splitgrade system - Green light for the low contrast prints.

[Tin Can]

That's interesting! No rail track! No at all! We have to put the enlarger approximately parallel to the wall, and it calibrates precisely by itself using the 3 lasers, which measures the distance to the wall in 3 points, and the whole enlarge with a lens and negative carrier swings, tilts and shifts to parallel everything!
It looks amazing in a real life, it already works! I will post some pictures or video later on...

Very interesting. Thanks for your specifics!

[Pere Casals]

This is a Splitgrade system - Green light for the low contrast prints.

This has to work very well, just some calibration may be useful to match ilford contrast filters...

Perhaps another possibility would be an spare UV led illuminator, IMHO present UV LED prices allows for an UV enlarger for alternative processes.

A nice feature of APO Nikkors is that they are corrected for UV until 380nm (source http://www.savazzi.net/download/manuals/Apo-Nikkor.pdf) , so focus can be done with blue light and later with UV source focus won't change, so no special digital camera is not nedded to check focus again.

I was thinking in that UV possibility... my guess is that it can be done by using a solar concentration fresnel to make it work like a condenser enlarger, this would improve efficiency, perhaps with a couple of cheap 50w UV leds exposure time may be in practical ranges, in fact regular UV arc lamps have a low share in the UV...

Just a thought... as enlarging to Platimun and Carbon would also be an awesome capability... digital negatives are fantastic, but having the capability to do it in a pure optical terms it is not a joke...

[mamanton]

No need to use any contrast filters, like Ilford, Foma or Kodak.

We use Green for low contrast, Blue light for high contrast, Splitgrade printing for any contrast from 00 to 5 (1/10 step), plus mixing mode for usual work, and White light for focusing, and very useful Red safelight to put the masks before the exposure.
And the timer includes f\stop mode and usual linear seconds (1/10 step also).

This has to work very well, just some calibration may be useful to match ilford contrast filters...

[bob carnie]

I am really impressed, now I have to get a 20 x24 setup to make a few negs, then fly to Russia to make a couple of split contrast prints.. Amazing project..

[Peter De Smidt]

Incredible!

[mamanton]

Welcome!

Next floor to our darkroom and the Gallery we have a guest room special for photographers, plus a small darkroom to develop the films and a larger format studio.

By the way, while we are waiting for the enlarger, we already received ulf 20x24'' camera!





The smallest camera on the picture - it is 8x10'' )) And my 2 years old daughter!

I am really impressed, now I have to get a 20 x24 setup to make a few negs, then fly to Russia to make a couple of split contrast prints.. Amazing project..