Enlarger Math

[bob carnie]

I need to produce an image 50 inches wide from a negative that is 7.5 inches wide. I am going to do this on my 11 x14 enlarger and unfortunately where
it is located I do not have enough height so I will eventually need to move it but I need some guidance on best optics first before I post more questions.

the negative is very narrow in height but it is 7.5 wide which will allow me to mask off.

Question 1. what focal length lens will give me adequate coverage for the negative which is 7.5 inches- I will be able to move the negative to dead nuts center.

I have 150mm and 210mm - my guess is the ideal size would be 180mm

[Taija71A]

Hello Bob,

Yes, just as you originally thought and as per our conversation...
An 180mm Enlarging Lens would be just 'Perfect' -- For your current Job Requirements.
(*Negative Size is 7.5" x 1". Coverage Required is 192mm ⌀. Magnification is 6.67X).
--
Thank-you.
Kind Regards, -Tim.
__________

[bob carnie]

Thanks Tim

that's what I like about this forum- ask a question and an answer is soon to come...

Bob

Now anyone with a 180mm lens for sale or interested in swapping one for a bunch of 80's or 50's ??




Hello Bob,

Yes, just as you originally thought and as per our conversation...
An 180mm Enlarging Lens would be just 'Perfect' -- For your current Job Requirements.
(*Negative Size is 7.5" x 1". Coverage Required is 192mm ⌀. Magnification is 6.67X).
--
Thank-you.
Kind Regards, -Tim.
__________

[Taija71A]

No problem Bob...
You are always more than welcome!

[plaubel]

unfortunately where
it is located I do not have enough height so I will eventually need to move it

Bob, if I'm right, the math behind says that in using a 180mm lens you will need a total distance, from paper to negative, of nearly 160cm.

Ritchie

[Taija71A]

+1. Agreed in full with Ritchie.
1587mm (±) is most definitely nearly 160cm.

[bob carnie]

Could either of you gurus of math tell me what the lens distance approx would be ??

[bob carnie]

So 160 cm = 63 inches from base board to bottom of glass carrier... wouldn't you know it that I got approx 59 inches so I will have to move the enlarger to the adjoining room that I can safe light which is exactly 6 inches taller and allow me to do this..

thanks guys


+1. Agreed in full with Ritchie.
1587mm (±) is most definitely nearly 160cm.

[Taija71A]

Could either of you gurus of math tell me what the lens distance approx would be ??

Sure!

Approximately 1380mm or 54.33" (±).
(*From your Paper... To the Nodal Point of your 180mm Enlarging Lens).

[bob carnie]

Thanks Tim

I think the glass position is more important now as I see I am three inches too short for where it is and I have 6 inches in the other room.. I see a heavy move in the next week.

Bob

Sure!
Approximately 1380mm or 54.33" .

[Taija71A]

Bob, is there "Any chance"...

That you can 'cheat' (Even just a little bit) in your 50" Print Length?
(*In order... To perhaps save you such a 'Heavy Move').

Like they say... "Just a Thought!" :)

[bob carnie]

maybe an inch but probably not more.I think the move is in order.

Bob, is there "Any chance"...

That you can 'cheat' (Even just a little bit) in your 50" Print Length?
(*In order... To perhaps save you such a 'Heavy Move').

Like they say... "Just a Thought!" :)

[Erik Larsen]

Have you tried your 8x10 enlarger by chance or does it have a taller light source or can't get to a big enough print?

[ic-racer]

I don't know about the DeVere 11x14, but most of the math for Durst Enlargers is simple, as they have a maximum print size for vertical projection about equal to the baseboard dimension. So, for 50"...your Durst 8x10 flips on its side, yes? Both of my Durst 8x10 enlargers were rescued from labs in which the enlargers were permanently set up for horizontal projection. I guess I'm a little surprised you don't have one of your enlargers set up for horizontal projection; you have the massive print tray, etc.
Here is a link to the math for horizontal projection: http://www.durst-pro-usa.com/pdf/MAKING%20BIG%20PRINTS%20IN%20SMALL%20ROOMS%20APENDIX.pdf
150360
150359
http://img.photobucket.com/albums/v670/ic-racer/DSCF4798.jpg

[Taija71A]

... I think the move is in order.

Agreed.
Based upon your Requirements... The 'Enlarger Math' is still not in your Favor.

[bob carnie]

Same issue with the 8x10
also I like the deveere for this kind of work the focus is so easy when I have the drop table to the bottom.

Have you tried your 8x10 enlarger by chance or does it have a taller light source or can't get to a big enough print?

[bob carnie]

Very little demand for horizontal set up, I do not want to do this at the current location due to space limitations.

I don't know about the DeVere 11x14, but most of the math for Durst Enlargers is simple, as they have a maximum print size for vertical projection about equal to the baseboard dimension. So, for 50"...your Durst 8x10 flips on its side, yes? Both of my Durst 8x10 enlargers were rescued from labs in which the enlargers were permanently set up for horizontal projection. I guess I'm a little surprised you don't have one of your enlargers set up for horizontal projection; you have the massive print tray, etc.
Here is a link to the math for horizontal projection: http://www.durst-pro-usa.com/pdf/MAKING%20BIG%20PRINTS%20IN%20SMALL%20ROOMS%20APENDIX.pdf
150360
150359
http://img.photobucket.com/albums/v670/ic-racer/DSCF4798.jpg

[bob carnie]

My third lab I worked at was Jones and Morris Photo Murals, - we had horizontal setups coming out of our rear ends.... I have lost my desire to make huge murals and have set on 30 x40 which does well in this
vertical setup.
When I moved to my own lab again from Elevator Digital I took a much smaller space and the horizontal setup was compromised. This job I am doing is the first request for a print over 40 inch on Silver Gelatin in two years.

[ic-racer]

You could just flip the head [of the Durst] for this one print, that is the beauty of the Horizontal/Vertical head.

[plaubel]

Could either of you gurus of math tell me what the lens distance approx would be ??

No Guruism necessary :-)
Depending on your lens, you could use easy math in using simple formulas.
In general, this is exactly the same stuff as with photographing close ups.


Let's say, you want to enlarge 3x.
Your ratio becomes 3:1.

So first multiply 3 with the FL of your lens, let's say 200mm; now you also have to add 1xFL (200mm), but I can't explain why, in english, sorry.

600mm+200mm gives 800mm.

Next, you have to divide your focal length 200mm : 3 (ratio), and to add one focal length:
This gives 66,66.. added with 200mm = 267mm.

Now you can check: Let's have a look at the given ratio:

800 : 267 = 2,99 ( 3!)
= 3 : 1

The 267mm is the negative distance, the 800mm is the enlarging distance.


Ritchie

[bob carnie]

Thanks Ritchie

[plaubel]

This formulas, out of my Durst Laborator book ( not the manual, but a real book), gave me an idea how and where to place my 12x16" enlarger in the next winter.

Good luck,
Ritchie

[bob carnie]

Just want to thank Len a member here for sending me a 180mm lens which I put on the enlarger and I was able to get my project height or width with this lens.

1/2 inch leeway from ceiling to top of the enlarger at the right magnification. This forum is the best for people reaching out and helping

thanks again for all who contributed.. You math geeks were all correct within mm of what you said.

I was not looking forward to move the big enlarger from one room to another.

Bob

[Taija71A]

'Good Stuff' Bob.
--
I am very glad... That it all worked out well for you!
(*Even after you called Ritchie and myself 'Math Geeks!'). LOLOL. ;)

-Tim.

[bob carnie]

Tim

When I call some one a geek or knob its with warm affection- I am glad there are the techno geeks out there that can figure out the details.

Here is a couple of pics with my pride and joy Durst 76- I have huge respect for the Durst techs who can balance the lasers.
Next I am bringing in a tech from States to work with me creating custom profiles for silver film to alt process.

I am good with the neg - print process - not bad with the PS - but really a klutz when it comes to the math. best regards Bob

151603151604


'Good Stuff' Bob.
--
I am very glad... That it all worked out well for you!
(*Even after you called Ritchie and myself 'Math Geeks!'). LOLOL. ;)

-Tim.

[bob carnie]

btw I should thank Brad Pitt for posing at my machine.

[Taija71A]

Hello Bob! :)

I of course... Was just 'Joking' with you Re: Your Math comment. *There was never any 'Offense' taken on my part.
I know of course... That your comment was just 'Thanks' (For all who contributed to this Thread). 'Nothing More and Nothing Less'.
--
Sorry, for the confusion...
Best Regards also! -Tim.

[Tim Meisburger]

Damn, Brad is looking a bit beat. Must be all those kids.... :rolleyes: