10x8 enlarger lens board distance

[scratched&grainy]

Hi there,
Does anyone know what the distances are for various size enlarger lenses to the easel?
I'm building a horizontal 10x10 enlarger and I've put in extra deep concrete (isolated from the rest of the concrete floor) in the floor under the enlarger. I want to do the same under the enlarger board but need to know more or less where to cut the floor and put in the extra concrete. Thanks,
Mark

 

[scratched&grainy]

In fact, I bought Ansel Adams' book 'The Print' especially for this. In it he states that he has a special table in Book 1!

 

[Bob Carnie]

I think ice racer here or on large format is able to answer this one, my horizontal enlarger is not set up , What would be important is to know the size of print you want to make???

Hi there,
Does anyone know what the distances are for various size enlarger lenses to the easel?
I'm building a horizontal 10x10 enlarger and I've put in extra deep concrete (isolated from the rest of the concrete floor) in the floor under the enlarger. I want to do the same under the enlarger board but need to know more or less where to cut the floor and put in the extra concrete. Thanks,
Mark

 

[ic-racer]

This is from the DURST PRO USA site. This distances for horizontal and vertical would be identical. As Bob indicates, you need to know your print size and need to know which enlarging lens. Do you have a lens yet?
http://www.durst-pro-usa.com/pdf/Projection Information for Durst Horizontal enlargers.pdf

Thin lens equation works also.
1/p + 1/q = 1/f

 

[scratched&grainy]

Well, the plan is to project onto about 170cm x 170cm glass that has been coated with emulsion since I can't find any rolls of paper any wider than 108cm.
But I also want to make smaller prints, maybe an enlargement of 1:3 from a 9x9 inch neg. I haven't got a lens yet, I'm still at the darkroom building stage. I'm converting a pig-sty into a darkroom/studio. I've poured out a 10cm thick concrete floor and can still cut into it at this stage and cast a concrete block where the enlarger will stand. I have already done this for a vertical 5x7 enlarger but a horizontal enlarger also needs the vertical board stabilized. Thanks,
Mark

 

[scratched&grainy]

Hey,
Thanks for that Durst table, that's exactly what I needed!
Cheers

 

[bernard_L]

extra deep concrete in the floor under the enlarger
I want to do the same under the enlarger board but need to know more or less where to cut the floor

If you want to make more than a single size print, you need to vary either (1) the lens-to-print distance or (2) the lens focal length (assuming same negative size). As the latter does not seem practical (zoom enlarger lens?) you cannot have both the enlarger head and the print board sitting on fixed concrete blocks. Look at pictures of horizontal enlargers: at least one of the two rides on rails.

 

[scratched&grainy]

I'm kind of thinking, I can stabilize the enlarger and the vertical board with cast concrete in the floor. Maybe additional rubber elements. And maybe if I later install some rails I could prepare the floor for them also? Is that Total over-kill?

 

[Bob Carnie]

With a horizontal enlarger, you need a solid flat floor that you can put rails on which will allow the enlarger to move away and too the wall depending upon the magnification.

This will require a bit of good workmanship.. the metal wall should be laser aligned to the enlarger at all magnification steps and you should understand that
the rails will have to be shimmed all along on both rails from front to back .. this is not a simple home improvement job.

Without doing this you will constantly be chasing your tail over print focus shifts, alignment issues and every time you change the enlarger position well I hope you see the problems.

If this Pig Sty is to become a permanent darkroom for murals , you should really do it right the first time.. Alignment at different magnifications will be the big chore.
Metal walls , magnets, now thats the easy stuff.
QUOTE=scratched&grainy;1953792335]I'm kind of thinking, I can stabilize the enlarger and the vertical board with cast concrete in the floor. Maybe additional rubber elements. And maybe if I later install some rails I could prepare the floor for them also? Is that Total over-kill?[/QUOTE]

 

[ic-racer]

onto about 170cm x 170cm glass that has been coated with emulsion since

Wow. I can't even imagine replacing or framing a window that size.

 

[RobC]

this software will give you all the numbers you want if you plug in the right variables.

http://www.winlens.de/index.php?id=70

 

[scratched&grainy]

So, have you made one of these? A horizontal railed enlarger for mural prints?
M

 

[RobC]

no but the software will tell you the track distance (film plane to print distance) for any combination of lens FL / film size(object) / image size(print) you care to input.

So you can work out what you'll need for the smallest film format and image size you want to print upto the biggest film format and print size. So that way you'll know how long to make your rails and where to put them relative to where you'll put your print.

You do have to set the right parameters though.

 

[scratched&grainy]

Thanks