Building a giant horizontal enlarger.

Bob Carnie · Dec 30, 2007

JBrunner said:
Thanks Bob,

I was considering mounting the enlarger in a fixed position, and having a movable easel. Easy repeatable registration will be the biggest problem, if I do that. It may work better with my space. I'm mainly trying to avoid having to fabricate a floor mounted track. The largest prints I plan to make would have a max of 40" inches on the short side (40x60 for instance), so I was thinking wallpaper trays if I can find them over 40" or if not, something along those lines, either constructed, or purchased, and a two man operation for development.

Your facility sounds incredible.

Jason
A movable easel will work quite nicely , You may want to consider a vertical setup,and stepping up to change filters bla bla bla, There was this guy in Canada who cut a hole through a second floor and projected down to make massive prints.
The floor track is not hard if you have room and will allow you to move the enlarger to the wall if you are doing other things.
I went to a plastic welder, any enviornmental silver recovery company in your area will know a dude who can plastic weld.
then make the trays to your size.. 46inches wide by 12inches bottom/deep on the inside measurment. Rolling the prints through a series of these trays is a piece of cake, make sure you wear gloves, longer than normal dev time, and consistant rolling.
Where you are going to find problems is toning, I had to make large trays for this ,, once again the plastic welder dude, they need not be as deep but should be able to hold a 40x60 inch print. you will need two.
Otherwise I would stick to dev, stop, fix, fix hypoclear and 1:20 selenium tone then final wash as your workflow.
Wash is done by the fill and dump method and quite frankly is a backbreaker and the biggest pain in the ass in the whole workflow.

I commissioned the plastic welder to make me a vertical slot washer.. 48Inches x 74Inches with six slotts .. I think it holds over 110 gallons of water.
This sucker is setting me back $5000 but we do a lot of murals here and will save a lot of hours in the long run.
BTW if you make the trays as I suggested it really is a one man operation, just need strong wrists. *I got mine from playing hockey, and other things not needed to be mentioned.*

Bob

richard ide · Dec 30, 2007

Erie,

I made similar masks for very big enlarger I built, I was making enlargements where exposure for some work had to be accurate to 1/10 stop or less across the image. I used this enlarger with 420mm,610mm,760mm and 1200mm lenses. I made a mask out of ortho film for each lens which I would place behind the diffuser in the head. I just exposed the masking film at 100% magnification and the thinnest area was about .02 density units above base fog.

Jim Chinn · Dec 31, 2007

Once you have the enlager placed in a permanent position, draw a pair of lines on the floor extending from the enlarger. Make sure they are square to the enlarger and parallel. When you build the movable easel for holding the paper, design a couple of line up points or targets on the bottom of the carriage. The wider the lines are apart from each other, the more accurate will be the alignment. As long as both targets align with the lines extending from the enlarger you will be in registration. Mark off the lines in 1" or 1/2" increments. Then you can record the distance for specific prints if you later do reprints.

Tommy · Dec 31, 2007

Jim Chinn said:
Once you have the enlager placed in a permanent position, draw a pair of lines on the floor extending from the enlarger.
...
Mark off the lines in 1" or 1/2" increments. Then you can record the distance for specific prints if you later do reprints.

How about using a laser pointer and some cards with holes in them? Mount the laser firmly on either the easel or the enlarger, and then attach two cards with holes on the front and back of the enlarger or easel (so the cards are a foot or two apart), such that if the easel and enlarger are lined up the laser passes through both holes. The laser has no equivalent to the distance marks though.

JBrunner · Dec 31, 2007

Tommy said:
How about using a laser pointer and some cards with holes in them? Mount the laser firmly on either the easel or the enlarger, and then attach two cards with holes on the front and back of the enlarger or easel (so the cards are a foot or two apart), such that if the easel and enlarger are lined up the laser passes through both holes. The laser has no equivalent to the distance marks though.

I could use side pointed lasers for distance.

"I asked for an easel with friggin lasers, throw me a bone here!"

Vaughn · Jan 1, 2008

Bob Carnie said:
Jason
I commissioned the plastic welder to make me a vertical slot washer.. 48Inches x 74Inches with six slotts .. I think it holds over 110 gallons of water.
Bob

Almost 800 pounds of water! I hope you got a structural engineer to check out those plans! That is a lot of weight pushing out the sides.

Vaughn

Curt · Jan 1, 2008

Consider: Two aluminum or steel rods, box or I beams fixed at the ends on two opposite walls over head instead of floor tracks. Suspend the easel from bearing hangers like a pocket door. Add locks and support rods to adjust and keep vertical.

richard ide · Jan 1, 2008

The easiest way to make sure your easel is 90 degrees to the optical axis is to use a mirror against the easel and view the image of your lens on the ground glass. If it is centered you are aligned. I put my monster enlarger on a steel track and when aligning, I sighted along the track to the mirror and back. I could see an error of a few thousandths of an inch. When finished I checked with a negative of a precision grid enlarged 5X. 2 lines 4 feet apart on the easel were parallel over 12 feet to within less than 1 mm. A first surface mirror works best. Depending on your easel mounting method; using lens/magnification math can be an excellent way of determining how much correction to make when adjusting.

wildbill · Jan 1, 2008

I always wanted to use a worm-drive garage door opener for something. hmmm. Seriously though, a track on the ceiling would be easy to do with a few parts. Here's what the typical local camera rental house has for testing focus on their lenses.

vinny

Bob Carnie · Jan 2, 2008

Tell me about it , when the sucker is done and full of water this thing is not moving. I will post an image when it is done , I do not expect delivery for a couple of months.

Vaughn said:
Almost 800 pounds of water! I hope you got a structural engineer to check out those plans! That is a lot of weight pushing out the sides.

Vaughn

Curt · Jan 10, 2008

Any new progress on the horizontal enlarger?

Curt

Nicholas Lindan · Jan 11, 2008

Vaughn said:
I hope you got a structural engineer to check out those plans! (48"x72" vertical slot washer) That is a lot of weight pushing out the sides ...

Ditto.

The total sidewall loading is 1 1/2 tons.

The sidewall area is 48 x 72" = 120 x 190 cm = 22,800 cm^2

The water pressure is 120 gm-weight/cm^2 at the bottom of the tank - the average is 60gm-weight/cm^2. (1 cubic cm of water weighs 1 gram)

The total side force pushing out on the outside walls of the tank is then:

22,800 cm^2 x 60gm-w/cm^2 = 1,368,000 gm-weight = 1,368 kg-weight = 3,016 lbs

I haven't seen the plans, but unless the design is such that you can turn it on it's side and park a car on it and leave the car parked on it indefinitely you may want to save yourself $5,000 and stop work on the project.

The loading on the inner septums will be zero if you fill all six slots evenly. If you try to fill just one of the slots then the septums will need to be as strong as the outside walls.

Advice worth price charged. Pilot's advice, captain's orders. Etc., etc..

Bob Carnie · Jan 11, 2008

Here are some specs , from the Welder who is going to make this

The tank must be welded before the inside floor can be put in. The end divider bars can then be welded in place. The dividers are dropped in last and not welded.ON the outside we should weld two inch bars to help prevent bowing out.
Working size would be approximately 40x60 and the unit would hold approximately 110 gallons of water, there would be four taps, the first two would be to regulate water flow into the tank from the pumps , To drain the unit I would put two second taps on the manifold and hose to drain.

8 sheets o f1/2 PVc
10 lbs of 8/32 welding rod
2 small pumps
fittings and hose.

*** my notes or observation***
water is evenly distributed into the bottom via pumps and the water raises equally as in most designs for a vertical washer.Therefore one channel will not fill up first then the next.

Any observations or advice is appreciated as it is a lot of money and I want this to work.

thanks Bob

Nicholas Lindan said:
Ditto.

The total sidewall loading is 1 1/2 tons.

The sidewall area is 48 x 72" = 120 x 190 cm = 22,800 cm^2

The water pressure is 120 gm-weight/cm^2 at the bottom of the tank - the average is 60gm-weight/cm^2. (1 cubic cm of water weighs 1 gram)

The total side force pushing out on the outside walls of the tank is then:

22,800 cm^2 x 60gm-w/cm^2 = 1,368,000 gm-weight = 1,368 kg-weight = 3,016 lbs

I haven't seen the plans, but unless the design is such that you can turn it on it's side and park a car on it and leave the car parked on it indefinitely you may want to save yourself $5,000 and stop work on the project.

The loading on the inner septums will be zero if you fill all six slots evenly. If you try to fill just one of the slots then the septums will need to be as strong as the outside walls.

Advice worth price charged. Pilot's advice, captain's orders. Etc., etc..

richard ide · Jan 11, 2008

Bob,
Did you consider a laminar flow washer. I jury rigged one using a 48 x 96 tank I built on a 45 degree angle when I no longer needed it for the original purpose. I got quite fast wash times and did not have to contend with a half ton of water. I flooded my place with other methods.

Regards

djhopscotch · Jan 11, 2008

Assuming you are using the 72" as the height of the container you have a max pressure of 2.6psi, it is an overall force of 4.48kips, assuming Static Pressure Calculation, the movement of the water through the system will lower the pressure slightly.

1.5" pvc can take 2.6psi as long as it is braced to prevent deflection. The take being plastic welded along three of the edges gives a total weld area of 72+72+48=192in. So your weld strength would need to be above 0.026k.in or 26lb/in.

Nothing about a tank like this is extreme, it is basically the same size as a large display fishtanks.

I assumed the 72" height since that gives the worst case loading along the weld. I would recommend a structural member along the top of the tank as well, to give you a larger area to distribute the loading.

My 2 cents as a structural engineering grad student.

Bob Carnie · Jan 11, 2008

Thanks

the height is 48inch by 72inch width. We will be making a walk up platform that two techs will put the paper in.. max paper will be 42 inches by 72 inches.
I have a 20x24 washer with no problems, I kind of was thinking this was much like a large fish tank which does hold much more water.

I really appreciate the info you folks are giving. I doubt that there will be standing water , rather a continual flow from the bottom with a constant drain during operation.
The welder works for a enviro company that is making large plastic containers that hold chems.
I will put this info in front of him, for his consideration

Richard at present we have a good system for washing singular or two prints but this washer should be able to do 12 prints back to back in six separate slots.

djhopscotch said:
Assuming you are using the 72" as the height of the container you have a max pressure of 2.6psi, it is an overall force of 4.48kips, assuming Static Pressure Calculation, the movement of the water through the system will lower the pressure slightly.

1.5" pvc can take 2.6psi as long as it is braced to prevent deflection. The take being plastic welded along three of the edges gives a total weld area of 72+72+48=192in. So your weld strength would need to be above 0.026k.in or 26lb/in.

Nothing about a tank like this is extreme, it is basically the same size as a large display fishtanks.

I assumed the 72" height since that gives the worst case loading along the weld. I would recommend a structural member along the top of the tank as well, to give you a larger area to distribute the loading.

My 2 cents as a structural engineering grad student.

Nicholas Lindan · Jan 11, 2008

Bob Carnie said:
Here are some specs

Can you post the drawings?

Nicholas Lindan · Jan 11, 2008

Bob Carnie said:
I kind of was thinking this was much like a large fish tank

What you are building is a 4 foot deep 6 foot wide -flat- dam. Imagine damming a 4 foot deep pond with a 4x6ft sheet of plywood.

It doesn't matter if you are holding back the Atlantic Ocean or just a hundred gallons - the pressure load is the same.

Bob Carnie · Jan 11, 2008

Looks exactly like a kostner washer except biggie size and materials.

Nicholas Lindan said:
Can you post the drawings?

Nicholas Lindan · Jan 11, 2008

Bob Carnie said:
Looks exactly like a kostner washer except biggie size and materials.

You may be in trouble, or you may not.

What you are attempting is certainly do-able. OTOH, it is a bit like going from a 20 foot trailerable boat to a 48 foot yacht: more than 'just make it two and a half times as big.'

If the tanks your contstructor makes look a bit like these:

http://www.tri-mer.com/pdf-files/poly_tanks.pdf (notice the steel outer support structure - you are going to need something like that).

then probably all is OK.

Bob Carnie · Jan 11, 2008

Holy crap batman , now that is one large washer,
I will definately raise the issues you all have brought up.
Bob

Nicholas Lindan said:
You may be in trouble, or you may not.

What you are attempting is certainly do-able. OTOH, it is a bit like going from a 20 foot trailerable boat to a 48 foor yacht: more than 'just make it two and a half times as big.'

If the tanks your contstructor makes look a bit like these:

http://www.tri-mer.com/pdf-files/poly_tanks.pdf (notice the steel outer support structure - you are going to need something like that).

then probably all is OK.

djhopscotch · Jan 11, 2008

Thats way over kill. You can buy a 150 gallon fish tank thats plexyglass on three sides. You need about as much support and a above ground pool for the depth of tank, those do not have structural steel surrounding them.

richard ide · Jan 11, 2008

Bob
It was a pleasure talking to you. I would suggest you talk to your fabricator concerning using polycarbonate instead of acrylic for the external elements. With a steel frame you could offset the cost by using thinner material and also for insurance. Polycarbonate would not be subject to the potential catastrophic failure you could get if acrylic cracks.
Regards

Nicholas Lindan · Jan 11, 2008

djhopscotch said:
You can buy a 150 gallon fish tank thats plexyglass on three sides.

The volume is not relevant to sidewall loading - only the height and width, with the load increasing as the square of the height. At 24" there's no problem, at 36" things get serious, at 48" with a flat sided vessel and you are at the tipping point, at 60" you are well out of the back-yard mechanic realm.

djhopscotch said:
You need about as much support and a above ground pool for the depth of tank, those do not have structural steel surrounding them..

Above ground pools are steel and they do have structural steel surrounding them. They are also round. If the vessel is round then the wall stress is tensile - you can fill a plastic bag up with water and it will sit there with no support. Now put that same bag inside a skinny cerial box and fill it up to the same height and you suddenly have a round box. Fill a round inflatable wading pool with 2 feet of water an there is no problem - try and push the sides in to make it square and you suddenly have a heck of a problem. Imagine a 48" wading pool and think about holding the sides flat...

If you look at 48" oval above ground pools you will notice the steel structure is butressed at the sides and the construction is quite a bit heavier. They usually have a deck around them - the purpose of the deck is to hide the reinforcement around the top.

The mess when a big above ground pool or aquarium gives way is impressive - and they all give way. Industrial tanks are designed _not_ to give way. To put it in photography terms: A Canon Rebel and a Nikon F6 do pretty much the same thing: one's for having fun and the other is for earning a living.

Nicholas Lindan · Jan 11, 2008

richard ide said:
I would suggest you talk to your fabricator concerning using polycarbonate instead of acrylic

The better choices would be polypropylene and polyethelene.

The cheapest construction would be a buttressed steel tank with a thin vinyl liner. Gee, does sound a bit like an above ground pool, but use 16 or 18 ga for the walls. Put the water goes-intas and outas at the top. Drain with a pump. Use a wooden drop-in frame with slots for holding loose septums - if it is a washer the inner compartments can leak a little bit of water from one to the other.

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