Darkroom frame

[joachimboegedal]

Hello!

Do anyone know of darkroom frames bigger than 60x70 cm? I need a frame around a meter i length and around 75cm wide, i can't seem to find any in that size.

Of course i can use loose parts to flatten the paper like magnets but when you have a margin of 1cm on each site, loose parts are a pain to work with. Otherwise i will try to build one myself.

[Tracy Storer]

Do you mean an enlarging easel? I have seen 4-blade easels as large as 30"x40"

[Drew Wiley]

There are plenty of used large vacuum easels out there, especially from old process cameras rather than simply enlargers. The graphics type tend to be way
better made, but also relatively heavy. Finding something with built-on masking blades larger than 20x24 inch image area will be difficult. I have always made
my own large vac easels. But there are distinct tricks to doing it well. So you might want to research what a well made easel from some graphics source like
Olec-Stoesser actually looks like. Sometimes you can get beautiful equipment downright free left over from big print shops if they still have it in storage.

[joachimboegedal]

Yes sorry, I mean easels. I can't find anything bigger than 20"x24

Drew - sounds good, I will look into that.

[MrFujicaman]

My copy of Petersen's Photographic's "Photo Equipment You Can Make" has plans for a vacuum easel. I'd be happy to copy the pages and scan them and email it to you.

[Tin Can]

Woodworkers make huge vacuum tables for vacuum forming with bags. 5x10 feet is common.

They have many designs up to ship sizes. Search for vacuum molding. They often use shop vacs.

Vacuum 'pressure' is always adjustable.

[Drew Wiley]

Woodworking vac rigs aren't intended for anywhere near the degree of accuracy (platen flatness) needed in photographic enlargement. And shop vacs have far
too much vac draw for a decent vac easel. In fact, I don't even recommend them for wood sanding because they aren't variable power, hold the sander too tight, and make a dusty mess. We use the more snooty term"dust extractors" here, and one pays accordingly. "Shop Vacs" are for cleaning your truck, and should never be anywhere near a darkroom unless you've got the hose running through the wall the unit outside. And common permeable substrates like pegboard are voodoo for a dkrm vac easel. I've seen the impression of the oversize dimple holes in finished prints, due to a slight shadow effect. You only need a few lines of 1/16" or 1mm holes properly arranged (again, look at true graphics easels). There is also the need of correct internal struts to keep the top flat when vac is applied, plus an internal arrangement that pulls the paper flat in correct sequence. This is especially important with certain types of big paper or film, which might actually be wrinkled if the application of vac is willy-nilly. The vac pump should be rotary, not peristaltic with a piston or diaphragm. These are abundant or can simply be improvised. Sorry to contradict you, Randy... but this is my field. Even serious woodworkers have given up on cheapo shop vacs. That's more a rough new construction item, and now illegal on older homes nationwide when paint dust is involved. Fine dust goes right through them, no matter what kind of
alleged filter is fitted on them. They aren't properly sealed. But vac easels are so easy to operate that one could simply hook up a little rechargeable handheld
vac to them, and do the job fine. You'd just have to recharge the batteries frequently, and dedicate the unit to keep dust out of it.

[Tin Can]

Of course refinement in anything is key.

Sometimes we need to start with basic concepts.

Many are discouraged by 'experts' always yelling IMPOSSIBLE!

[Drew Wiley]

The whole point of even using a vac easel is to obtain focus precision. Otherwise, for big prints, one could simply use a magnetic perimeter strip like mural printers
do. Many of us have seen those cute old Pop photo style articles equivalent to Popular Mechanics giving you an illustrated diagram on how to make your own nuclear submarine with spare washing machine parts. I even have a minor collection of those kinds of nostalgic articles, but also know they're basically nonsense.
Most people outright forget that when vac is applied, the whole top is going to flex inward, or that your paper can actually get dimpled too, if the holes are too big.
That's why I think it's best to take a more direct approach, look at pictures and diagrams of serious gear on appropriate websites or catalogs, and ask why they
chose to do things that way.

[Tin Can]

Of course.

I like people to understand concept before refinement.

Many of the vacuum forming tables are very well designed and of course deal with different parameters.

Drew, you are big on description but I don't recall any images to aid in understanding your techniques and equipment.

A picture is often worth 1000 words.

[Drew Wiley]

Yeah... no contest there. Other than my wife's cell phone and her underwater Nikon, we don't have any digital cameras around to quickly post this or that; nor do I have much time to do that kind of thing right now. Still have a day job, where I obviously get minor breaks to post this n' that, and then maybe onto remodeling chores in the evening, which at the moment involve both the lab and our house. I am making excuses, but perfectly reasonable excuses for someone in their mid-60's who can't seem to burn the candle at both ends anymore! Toward the tail end of the former project, once I have my new dream copystand setup (the old Bencher rig just went to the scrap heap), then I'll look into updating web and posting options with some kind of DLSR suitable for quality work. Got bigger fish to fry in the meantime. But in terms of vac easels, formal mfg websites like Olec-Stoesser are readily accessed under the relevant description, and all one has to do in terms of used equipment in search vac easels under Industrial gear on places like EBay, rather than under the Camera section.

[Jim Jones]

The whole point of even using a vac easel is to obtain focus precision. . . .

For me the whole point of making a vac easel was for borderless prints. The holes were much smaller than those in pegboard. Internal bracing made the easel as sturdy as some commercial bladed easels and insured far more flatness than needed for enlarging. A retired Rex-Air household vacuum provided plenty of suction. All of my photography is personal or pro bono. There are no clients to foot the bill for luxuries.

[John Layton]

I made a very serviceable easel from a piece of 2x4ft melamine board - cut this to 2x3ft, then routed shallow rabbets into strips of 3/4 square stock and spray painted these flat black - then screwed these strips to the melamine. 21x30 inch paper (cut from a 42 inch wide roll) slides nicely into the tracks, and the paper stays plenty flat given the reasonable DOF present at the paper plane. My next goal is to make a 30x40 inch version of this to go with my DIY horizontal enlarger.

Keep in mind that the most critical aspect affecting integrity of focus are the congruence of negative plane with overall easel plane. While DOF at the negative plane is extremely small, the DOF at the focussed image plane is a wee bit more generous, given a lens aperture of "medium" value (such as f/11 to f/16 for my 180mm with 5x7 negs)... enough to allow for a small amount of curvature along the paper borders, and an equally small amount in the center - as is the general profile of papers held within a non-vacuum easel. On the other hand, if I were consistently needing to use my maximum aperture or close to this, as in working with very dense negatives or wanting to speed things up for any reason, then yes, a vacuum easel would make sense.

[Drew Wiley]

Thick melamine coated MDF is a good low-cost option provided it is coated on both surfaces, and that you fully seal any shallow air channels you've routed in the
back, as well as the board edges, to prevent warpage. Then you obviously need to have a secondary backing to cover the channels and further stiffen the whole
device. If you use a second sheet of 3/4-inch melamine board, you'll end up with a very rigid and agreeably solid and heavy easel 1-1/2 inches thick. The trick to
gluing melamine back to back is either fresh Roo Glue or fresh Gorilla Glue, very tightly clamped overnight. Remember, Gorilla Glue is humidity activated, and
spreads laterally, so you don't want it to spread to the point of filling your air channels. Finding black melamine MDF can be a bit tricky, but specialized plywood dealers often carry it.

[Jim Jones]

For a lighter and cheaper easel, two layers of thin plywood, hardboard, or MDF can be separated by a grid of internal bracing. This eliminates the need for routing. My vacuum easel was lost decades ago in a darkroom fire, but as I recall it was made of 1/8 tempered hardboard with a smooth hard surface. The grid stood about an inch tall. This construction (flat surfaces bonded to an internal web) is rigid somewhat like a T-beam, and much lighter than solid construction. It also works for enlarger bases if the web is properly laid out. The small holes were spaced 1/2 inch for any size print if the area outside the print was masked.

[Tin Can]

Here's a video of something similar. (https://www.youtube.com/watch?v=fOrkvPF0pro) I like how the demo shows how simple a vacuum table can be, how small and cheap the vacuum can be and how to use the same vacuum to suck and clamp the whole thing while glueing with Elmers.

A photography table would as, Drew describes, use very small holes and low vacuum, which can be adjusted with simple bleed off port.

The big rectangles can be cut at Home Depot, which I almost always do, mine cuts for free. And the slot wood could be bought in the trim wood department which is already dimensionally exact. Cut to length, glue, vacuum clamp, drill holes. Make a bleed from PVC water valves. One stop shopping, almost no home sawing. Use a sheet of kitchen counter top laminate for the top and anybody can drill all those holes by hand.

[Richard Wasserman]

I want the CNC router!

I would think a properly designed torsion box ala Jim Jones above would be a very good way to go. It would be lightweight and very strong and rigid.

My Home Depot refuses to cut Melamine because they don't want to be responsible for chipping. I solved that problem and many others with a Festool Track Saw—what a gem it is...


Here's a video of something similar. (https://www.youtube.com/watch?v=fOrkvPF0pro) I like how the demo shows how simple a vacuum table can be, how small and cheap the vacuum can be and how to use the same vacuum to suck and clamp the whole thing while glueing with Elmers.

A photography table would as, Drew describes, use very small holes and low vacuum, which can be adjusted with simple bleed off port.

The big rectangles can be cut at Home Depot, which I almost always do, mine cuts for free. And the slot wood could be bought in the trim wood department which is already dimensionally exact. Cut to length, glue, vacuum clamp, drill holes. Make a bleed from PVC water valves. One stop shopping, almost no home sawing. Use a sheet of kitchen counter top laminate for the top and anybody can drill all those holes by hand.

[Tin Can]

A cheap ready made torsion box is a hollow interior door, also at HD.

Then make a shallow network of woodstrips for the vacumn routing.

A 36" X 72" door would be quick, cheap. Heck I already have that same little vacuum from the video and I think building on a hollow door may be my ticket. I'll use the store's tools to check flatness on 'my' door.

I already use one of those hollow doors as a dry table on top of one of my sinks when I need more dry space. It's supported on 3 sides and doesn't bend. Lightweight for quick change. Also free.

[Drew Wiley]

Please... no more mention of those damn track saws. I'm outright exhuasted just trying to get those things in here as fast as I sell them. And I actually stock more items than the entire catalog itself. Anyone want a job? I want to retire. But heck, just remember to use a true melamine blade. What NOT to do: don't use pegboard for your easel. I already mentioned that. Way too many too big holes. Maybe you'll get lucky and find an air hockey metal table at the dump. I got lucky and was given a machined steel pin-registered precision easel from a 22ft long process camera, then added the masking blades. But it weighs a couple hundred pounds. However, I've made several lightweight big vac easels. 1/4" thick polycarbonate sheet is nice to work with - another rail saw no-brainer. What is HD, Randy? Isn't that where people go for sandbox and doghouse lumber?

[Tin Can]

Yep, Home Despot, land of crap.

I am not Suzy homemaker and would prefer to live in a tent, but have to settle for a cement cave, at least this old factory has very thick walls. My friends at aptly named BulletProof Film share the building.

Tonight I am fooling with a Graflarger, just about as far as one can get from perfection.

Pictures later, if I can figure out where to put small format enlarging...

[Richard Wasserman]

Drew, I thought you might appreciate the saw reference. I'll do you a favor and not mention the router and dust collector...

[Tin Can]

What next, lawn mowers?

[Richard Wasserman]

Don't get me started...


What next, lawn mowers?

[Tin Can]

Don't get me started...

At least I have no grass man. That's a pun or double entendre.

:)

[Drew Wiley]

I've got sixty grand of Festool sitting in the next room that hasn't been put away yet, more across the street, two more trucks in transit, and am still doing paperwork for more. Then there's Fein, Metabo, Bosch. I call my office, "Little Germany". I'm worn out. Of course, true to the Euro theme, I'll be packing the Norma tomorrow, albeit with only one German lens (a G-Claron) - the rest will be Fuji's. Don't tell anyone!

[denverjims]

Sorry to come in with such a low tech solution. I had found a box of paper once which was fine except had some stiff curl from being dried out in our low humidity climate. Rather than trying to build/buy v. easel, I found that some double sided artist tape applied to my Saunders base worked well. Thin, held paper flat & did not put residue on paper. After done w/ that paper, easily removed.

[Drew Wiley]

Holding edges down can be accomplished simply by the adjustable masking blades on easels which have them. If you paper still has too much curl, a bit of removable masking tape applied to the blades and frame (not paper itself) is a suitable solution. But this does not hold the entire piece of paper flat. And it can
still buckle during exposure. A good vac easel with solve both problems.

[denverjims]

Drew, you are right and I did not think to add that the Saunders has blades for the periphery. Those and the 'badge' magnets on the blades seem to do the job around the edge.

My problem was the center of the 16x20 paper w/ the curl. Since I store my paper face down with a flat weight on it and have outfitted my paper safe as a humidor as well, I have been lucky enough not to have much low humidity curl on fresh paper. If I did, I'd definitely think v.easel as you suggest.

As it was, with the problem only being with that one paper batch I did not want to go to the trouble & expense of v. easel when the tacky (not sticky) double sided artist tape seemed to do the trick.

[Drew Wiley]

You can actually turn the Saunders Pro easels into vac easels if you seal up the back and slots, and add the necessary holes and vac port. Not perfect, but good
enough for most purposes. Or cannibalize the just the masking blade assembly for something more seriously fabricated. I have done both, plus totally home-made
rigs.