Home Made/DIY ULF Vacuum Film Holder/Back - Seeking Advice

[Qeb]

Greetings Everyone!

I hope you are all happy and healthy right now!

So, what do you people think about vacuum backs for ULF/Mammoth cameras when using film or direct positives.

I've searched the internet and found some advice.
1. Some posts on vacuum easels for contact printing
2. I've seen the conversion of 4x5 / 8x10 film holders with small vacuum pumps with suggested pressure bleed off valves but also including that holes should be around 1/16 inch to 1/32 inch in diameter.
3. Saw mention about sticky tape but didn't find the details.

I'm hoping someone can give some advice on building a vacuum back from scratch or another way.
My Chamonix camera, the ground glass and film/plate back are separate and removable/interchangeable so I would need to build the hole back.
I can get help with this, but I don't know about the vacuum part.
For example, what size pump or multiple pumps would be needed (I never followed with a science degree in University - I took a fine art degree haha).

The project is to get into direct positive / paper negatives 16x20 inch or larger down the road when I can find get a studio/space for a darkroom (I moved a few years ago and gave all my darkroom equipment to my old high school photography program)

I'm right now assuming I will need someone sort of vacuum or other method to keep the paper negatives in place unless someone knows about that tape method (I don't think it's just taping down the perimeter of the paper).


Any thoughts/knowledge sharing would be much appreciated!
Thanks for reading!

Be safe out there everyone!

Cheers,
Kevin H.

[pvan93]

Try looking for an old Argyle copy camera. Or photos of one. The larger #23 had a 19x23 vertical back and a 5’ bellows on a fixed 6’ aluminum bed. No movements, but very mobile in a 6x12 cargo trailer kind of way.

Ok flame me. But 100-300 camera and a 1200-2000 trailer. The hard part is feeding the monster...

[pvan93]

Oh, and a $5 #1 Doppler for a portrait lens.

[Duolab123]

My buddy has a 16 x 20 process camera. A baby. Vacuum backs that swing in and out are a joy to use. I had an opportunity to get a back off a huge process camera, film was 36x48 inches, the back was bigger than that. I think the back weighed 2-300 lbs.
You should be able to find a piece of material somewhere. All that stuff was scrapped. These had a control that allowed you to adjust how much of the back received suction. It adjusted to smaller film sizes. Roberson made beautiful high end cameras, all extinct.

[Drew Wiley]

Since this involves a Chamonix camera, a degree of portability is no doubt in mind, which would rule out a graphics style back weighing even more than the camera itself! Let's start with the vacuum draw device. A simple handheld cordless vacuum cleaner has plenty of suction. You just attach it with a short length of vinyl hose. The battery will have to be frequently recharged or a spare needed. If you have a typical two sheet filmholder, you sacrifice one side for sake of the vacuum chamber. You drill an intelligent X and perimeter pattern of 1/16" inch holes through the central septum. Then on the backside, with the darkslide removed, you need to glue in little shims the thickness of the air chamber to prevent the septum from deflecting when the vac is on. Then you drill a hole on toward the non-insertion end big enough for a little tail or two brass miniature tubing to accept the small vinyl hose. Then the rear darkslide is glued back in with black silicone caulk to make it air tight. The front half of the film holder remains normal.

[Qeb]

Hey, Thanks so much for the thoughtful replies everyone!

Thanks for the idea to use a handheld cordless vacuum cleaner! Great idea!
Thanks also for the other instructions!

May I ask you Drew, how big of a film/paper do you think a hand held cordless vacuum cleaner can hold in place?

Do you think the film/paper needs to be vacuumed as soon as you put the paper in the film holder/back or only when you expose?
I guess it depends if the film/paper holder has those retaining lips at 3 sides (think of a standard 4x5 film holder)... hmm.

Thanks again everyone!
Take care and be safe
Cheers!

[Drew Wiley]

Well, in the lab I have a 30x40 inch vac easel for thick polyester papers that does weigh several hundred pounds, and a little handheld battery vac (a decent Makita one) easily holds the paper flat. To save battery life, I more often use a very small plug-in vac instead; but in that case, I actually have to bleed off surplus suction! And yes, as long as the edge or perimeter is retained, you apply the vac just prior to exposure. But you want to design the hole pattern carefully, with the extraction tube going internally to the center first.

[Qeb]

Wonderful,

Thanks so much Drew Wiley!

I've saved your posts and will try this in the, hopefully, near future!

Be well everyone!
Cheers

[Jeff T]

Hi Kevin,

I have a 8x10 vacuum film holder. It appears to be a very good DIY job, however, I have not a chance to use it.

Jeff Tran

[Greg]

Have seen rather little battery powered vacuums that remove air from storage backs used for holding clothing in suitcases when one is traveling. Most powered by USB, which of course is of no use in the field, but there are battery powered ones out there. Seems like they would work great for a vacuum film back in the field. They are not all that powerful, but then I don't think a vacuum film holder really requires a super strong vacuum to work.