Building a Darkroom

Hello all. I have a couple of questions in regards to building my darkroom.

1. I have tried to make my enlarger stand stable. Into each leg (4x4 wood material), I have screwed a bolt with threads and an adjustable nut on the end, so I can individually adjust the height of each leg individually to compensate for an uneven basement floor.
This table weighs easily 60 lbs, and it's braced, cross-braced, glued and screwed together with 5" long screws. It has a shelf in the middle and the top is a 1" thick piece of furniture grade plywood. I can't get this sturdy enough where my enlarger sits still. What am I doing wrong? I am frustrated beyond belief.

2. I have a small window, which I plan on opening when I'm in the dark room, cover it with a piece of black painted plywood, in which there will be a little squirrel cage fan mounted with a light trap. Any good ideas on building a functioning light trap that will filter out possibly daylight?

3. General ventilation. It's in a basement, which means moisture is a major problem in the summer due to humidity levels upwards 80% or so. Mould can easily appear. Every surface, even the inside of the walls, has been painted with mould resistant primer after a thorough cleaning process. Should the draft be that the ventilation holes are at the floor and sucked up to the window for proper air flow? I was thinking of drilling holes in the two surrounding plaster walls. The walls are built from 2x4 material and there's drywall on each side. For the 'outside' I want to drill holes at the top, and on the 'inside' I want to drill holes on the bottom (inside of the walls are painted matte black). Does that make sense from a ventilation standpoint?

I know these questions are long, but any feedback would be greatly appreciated.

- Thom

huggyviking said:

Hello all. I have a couple of questions in regards to building my darkroom.

1. I have tried to make my enlarger stand stable. Into each leg (4x4 wood material), I have screwed a bolt with threads and an adjustable nut on the end, so I can individually adjust the height of each leg individually to compensate for an uneven basement floor.
This table weighs easily 60 lbs, and it's braced, cross-braced, glued and screwed together with 5" long screws. It has a shelf in the middle and the top is a 1" thick piece of furniture grade plywood. I can't get this sturdy enough where my enlarger sits still. What am I doing wrong? I am frustrated beyond belief.

Click to expand...

Screw it to the wall, or use thse "bullet powered" cement nails.

2. I have a small window, which I plan on opening when I'm in the dark room, cover it with a piece of black painted plywood, in which there will be a little squirrel cage fan mounted with a light trap. Any good ideas on building a functioning light trap that will filter out possibly daylight?

Click to expand...

PM Sent.

3. General ventilation. It's in a basement, which means moisture is a major problem in the summer due to humidity levels upwards 80% or so. Mould can easily appear. Every surface, even the inside of the walls, has been painted with mould resistant primer after a thorough cleaning process. Should the draft be that the ventilation holes are at the floor and sucked up to the window for proper air flow? I was thinking of drilling holes in the two surrounding plaster walls. The walls are built from 2x4 material and there's drywall on each side. For the 'outside' I want to drill holes at the top, and on the 'inside' I want to drill holes on the bottom (inside of the walls are painted matte black). Does that make sense from a ventilation standpoint?

Click to expand...

Ideally the air should be pulled from just above the backsplash on your sink, that way it does the best job of pulling the fumes away from you. Not such a simple engineering project in most rooms I'm afraid.

Bruce

Hello.

Just two thoughts:

First of all you say that your table is braced, cross braced etc. Is the unsturdiness you get a flexing of the top surface to the leg joints? The thing to remember with bracing is that triangles have inherent strength and resistant to movement whereas rectangles can easily move and become parallelograms without too much trouble. If by cross bracing you are refering to diagonal bracing then you have probably done all you can already.

With reference to the mould resistant primer, this will only protect the walls, the moisture will still be present. A good airflow will help this situation as you suggest but depending on where the moisture is coming from, you may need to vent the inside of the wall with drywall either side as well.

Sorry if any of this is obvious but it's better to have too much information than too little.

Steve.

Bruce,

you're very kind in helping me out. I'll have a hood over the sink, so that's not an issue. It's more a question of the general ventilation in the darkroom, so I don't get air trapped in there. For a while I was toying with the idea of putting in a heat recovery ventilator and keep it running all the time...

- Thomas

Steve,

you're right. Better with too much info... I agree with your statements on bracing. The braces are diagonally installed between side legs and the rear legs, so three sets of cross braces (they are vertical). Then there's a horisontal cross brace underneath the table top, to which it's attached. All cross braces are secured on either end, and then joint where they intersect.

Your idea about the ventilation is one that I agree with, and my solution is trying to accomplish that. Maybe I did a poor job in describing it...

Thanks for your help,

- Thom

Steve Smith said:

Hello.

Just two thoughts:

First of all you say that your table is braced, cross braced etc. Is the unsturdiness you get a flexing of the top surface to the leg joints? The thing to remember with bracing is that triangles have inherent strength and resistant to movement whereas rectangles can easily move and become parallelograms without too much trouble. If by cross bracing you are refering to diagonal bracing then you have probably done all you can already.

With reference to the mould resistant primer, this will only protect the walls, the moisture will still be present. A good airflow will help this situation as you suggest but depending on where the moisture is coming from, you may need to vent the inside of the wall with drywall either side as well.

Sorry if any of this is obvious but it's better to have too much information than too little.

Steve.

Click to expand...

huggyviking said:

I can't get this sturdy enough where my enlarger sits still. What am I doing wrong? I am frustrated beyond belief.

Click to expand...

After you bolt the table to the floor, do yourself a favor and get a wall-mount bracing kit for your enlarger (what make and model?). This will anchor the top of the column to the wall. In my history it is the tall, unstable column that "resonates" vibrations from people walking upstairs. Attaching this to the wall will make it structurally part of the wall.

I have an LPL 4550 XLG and I anchored the bottom into an enlarger table and then got the LPL anchor kit. The top of the column comes off and you install an "L" piece of metal that then screws into a stud.

Also, you should think about giving your table more surface area conecting the table to the floor. Instead of 4 contact points, connect the legs together with 4 pieces of wood that are drilled into the floor and connect each. Does this make sense? Leveling those pieces is critical.

Also, remember that for an exhaust to function, you need a source of fresh intake air. Doran makes (still?) a light-tight baffle that I installed in my wall by the entrance. Try to put this diagonally across from the vent so that air is pulled through the length of the room and exits above the sink so it takes the chemical smell with it.

--Jeffrey

1. Sounds like you are following the "brick outhouse" approach to building your enlarging table. My experience is that bracing and cross bracing are fine, but the best way to stiffen the table is to bolt it to the wall.

2. Light rays travel in straight lines, so a light trap needs corners that light can't go around. One way is to build a box with the inlet and outlet on opposite sides, but also at opposite ends of their respective sides. If the box is big enough, and the interior is painted black, that may be an adequate llght trap. You can add a measure of protection by installing baffles inside the box - two baffles each the full width of the box and slightly more than half the depth, with one attached to each face of the box (so that they overlap) create a maze-like path for air flow that light can't get through.

3. The best ventillation is positive pressure - where the ventillator fan blows air into the darkroom. If you have a fan that blow air out, it will pull air in through both the intended ventillation ports as well as any other nook and cranny that it can find, pulling dust along with it. Positive pressure ventillation, with a filter over the fan, is the best way to control dust and is the only way to assure that you control where the inlet air is coming from. Then, to address the humitidy problem, the best solution would be to arrange to have the inlet port on the first floor of the house so that you are not pulling in the damp air in the basement.

No need for a special bracing kit. Go to the hardware store buy two eye bolts, two eye hooks and two turnbuckles. Screw the eye hooks into the floor joists overhead and slightly behind the enlarger. Drill a couple of holes in the top of the enlarger carriage top brace for the eye bolts and hook them together with the turn buckles. Then bolt the table to the wall and the enlarger base to the table. You are now bulletproof. Until a fully loaded dump truck drives by.

A wall mounted vent fan with a dryer vent flap on the outside should take care of airflow. Home Depot will have a bunch set up for testing. Buy the more expensive one that's quiet. My set up is lightproof and so quiet I keep leaving it on by mistake.

A dehumidifer will take care of the excess humidity. The down side is it will add a little heat. I turn mine off in the morning if I'm going to work in the darkroom. Buy the model that allows you to set the percentage of humidity. This can be a big help if you Pt/Pd print. It also keeps it from running to much.

I rebuilt my darkroom of twenty years two years ago. Best extra was a Bose CD radio.

Would this be a turnbuckle?
http://www.acehardware.com/product/...buckle&parentPage=search&searchId=17123064301

photobum said:

No need for a special bracing kit. Go to the hardware store buy two eye bolts, two eye hooks and two turnbuckles. Screw the eye hooks into the floor joists overhead and slightly behind the enlarger. Drill a couple of holes in the top of the enlarger carriage top brace for the eye bolts and hook them together with the turn buckles. Then bolt the table to the wall and the enlarger base to the table. You are now bulletproof. Until a fully loaded dump truck drives by.

A wall mounted vent fan with a dryer vent flap on the outside should take care of airflow. Home Depot will have a bunch set up for testing. Buy the more expensive one that's quiet. My set up is lightproof and so quiet I keep leaving it on by mistake.

A dehumidifer will take care of the excess humidity. The down side is it will add a little heat. I turn mine off in the morning if I'm going to work in the darkroom. Buy the model that allows you to set the percentage of humidity. This can be a big help if you Pt/Pd print. It also keeps it from running to much.

I rebuilt my darkroom of twenty years two years ago. Best extra was a Bose CD radio.

Click to expand...

huggyviking said:

Would this be a turnbuckle?
http://www.acehardware.com/product/index.jsp?productId=1288106&cp=&origkw=buckle&kw=buckle&parentPage=search&searchId=17123064301

Click to expand...

No.

Try: http://en.wikipedia.org/wiki/Turnbuckle

If you would like a (digi) pic of how I did mine - send me a PM with your email address.

Cheers, David

Dear Thom,

Seriously consider a dehumidifier. Our darkroom is in an old (?200-year-old) wine cellar built into the side of a hill, and dehumidifying is all but essential.

Cheers,

Roger (www.rogerandfrances.com, where there is a picture of our current darkroom, and a couple of previous ones, in the free 'our darkrooms' module in The Photo School).

"Our darkroom is in an old (?200-year-old) wine cellar......"

Now that's handy!

BTW: The church photo looks much smoother. Of course, it could have been my monitor.<g>

Neal Wydra

Neal said:

BTW: The church photo looks much smoother. Of course, it could have been my monitor.<g>

Neal Wydra

Click to expand...

Or my scanning...

Cheers,

R.

Huggy, The link David gave you is what you want. I have used the eye bolt, turn buckle system on a Omega DII and now my Durst 138s. What's nice is because of the adjustable tension you can really keep the enlarger in alinement.

I wonder about your bolts for adjusting the height of your table. I did one that way and it was unsteady, so I just built up underneath the legs with blocks tolevel the whole thing. It was/is very solid.

By the way, how do you test for vibration?

Put my hand on the enlarger to test for vibration. I think I narrowed the problem down to the top sheet of 1" plywood not being sturdy enough. I will use the buckle and hooks method plus bolt it to the wall, after I put another layer of plywood on there.
The bolts are not really an issue. I made a stereo rack like this six years ago, and it holds almost 200 lbs of equipment without moving even a bit (it also has to be extremely sturdy due to the use of a turntable rather than CD player). In fact, it drains vibration to the floor.

Thanks everybody for helping out!

- Thom

huggyviking said:

Bruce,

you're very kind in helping me out. I'll have a hood over the sink, so that's not an issue. It's more a question of the general ventilation in the darkroom, so I don't get air trapped in there. For a while I was toying with the idea of putting in a heat recovery ventilator and keep it running all the time...

- Thomas

Click to expand...

My darkroom is also in a basement, although it is a bit better with regard to water vapour penetration in the summer. I am in southern canada, and my house is about 30 years old. I have renovated the basement and now the exterior walls of the whole basement are insulated and vapour barriered off. The concrete floor is painted/sealed throughout the basement to minimize moisture penetration, and also reduce the number of cavities for dust to settle into. There is a door at the top of the stairs that we keep closed in the summer. The central air conditioning system looks after most high moisture control in the whole house (all ducts supply duct in the basement get closed during A/C season or it gets quite cold down there), and a separate stand alone dehumidifier is set to come on and keep the basement humidity at below 60%RH when it isn't hot enough outside for the A/C system to be running to do the job.

I have ventilated my darkroom with a heat recovery ventilator as part of the system. The air intake to the darkroom is down low, on the dry side. It traverses a joist space to the outside inlet high on the wall in the hall outside the darkroom. The cavity of that joist space is painted flat black, and there is a cut down furnace filter media piece set behind the inlet grille to cut back on more dust. The high inlet in the hall is there on the principle that most dust settles, and this hall sees little traffic anyways.

The darkroom exhaust is located on the end of the sink, just above the lip, next to where the fixer trays sit when I am doing B&W. The exhaust from this darkroom vent feeds directly into the stale air intake of the HRV.

The door to the darkroom is a pocket door, with swipe gaskets around it, and it sits into a pocket constructed from millwork molding trimmed in swipe gasket like on sliding glass doors, to encourage air to use the inlet filter, not to come in around the door. The pocket door in addition to allowing a narrow hallway, also minimizes the amount of dust that gets stirred up when it is opened.

The sliding door, it pocket, and a step over sill pocket also form the light trap to allow work in the darkroom while the adjacent rec room has all the lights on. This light seal is hard to achieve with a conventional swing opening door, I have learned from past darkroom efforts at different places I have lived.

The fresh air output of the HRV is routed into the cold air return on the household heating system. In the summer the HRV doesn't run at all unless I am in the darkroom. I turn it on when I get into the darkroom, which in the summer is really not all that often. Summer is when mostly I shoot images to work up over the winter, and in the wet spring and fall times

The walls of my darkroom are painted drywall, and the ceiling is 2x2 white painted drop in tiles on a tbar grid. Behind the drop in tiles the bottom of the floor joists have a layer of plastic stapled over them to reduce the amount of microcrud that drops when people walk over the floor upstairs. I could not bring myself to drywall seal up the basement ceiling over the darkroom- to many changes are likely to occur that will need to get in there in the 30+ years that I continue to plan living in this house, since the electrical panel is in the laundry room adjacent to the dark room.

The reason that I took the negative pressure route is that I also store and mix from scratch my b&w and colour chemistry in and over my sink.

When I mix dry chemicals I put a board over the sink right beside the exhaust vent. There is a switch that I have wired and placed next to the exhaust vent to force the HRV into high speed mode. I turn it on when the dry chemicals are being weighed out, and dumped into the mixing bucket that goes onto the magnetic stirrer. The scale goes next to the exhaust, so that any fines stirred up as mixing spoons of chemicals are poured onto weighing paper on the scale go zoom out the exhaust before they can find their way onto every odd surface within the room itself.

Semi annually I open the HRV, and gingerly remove its inlet screens and core. I place them into a garbage bag and take them outside, and rinse them with the hose to clean them. All the while I wear rubber gloves and a mouth and nose particulate screen. I vacuum the drip tray with our central vac hose. The power unit for this vaccuum is in the garage, so there is no vaccuum exhaust to recirculate inside the house. I change and launder my clothes separately immediately after doing this work, since some of the developing agents for colour work are nasty.

I know that storing and mixing chems in the darkroom is against conventional wisdom, but I have small kids, and they know not to go into the room unless I invite them in. In fact it is usually locked.

Hope some of this can guide you with HRV options.

huggyviking said:

I have tried to make my enlarger stand stable.

Click to expand...

Why a stand? Why not set the enlarger on a counter?
Attach a platform, upon which the enlarger will rest, to the
wall. If possible use three right angle steel or aluminum joiners.
The attachment area of the shelf underside should be
strengthened with a narrow full width section of
board. Counter sink the attachment bolts
for a clear board area.

Attach legs at a near front location in the same manner
used to attach to the wall. Repeat all the preceding
using a shelf created by joining wall and legs. Think
upside down for the shelf or shelves if you'd like
more than one.

Buy best quality FLAT board for top and shelves and
furniture or finish grade hardwood 1x4s for the two
legs. Dan

Mike Wilde said:

The darkroom exhaust is located on the end of the sink, just above the lip, next to where the fixer trays sit when I am doing B&W. The exhaust from this darkroom vent feeds directly into the stale air intake of the HRV.

Click to expand...

In addition to all the good ideas already mentioned in this thread, I also work with an 'air sheet' flowing over my trays. Without an air sheet your ventillation system is not as effective as it could be.

refer to this post (there was a url link here which no longer exists) for more information

regards
Peter

dancqu said:

Why a stand? Why not set the enlarger on a counter?
Attach a platform, upon which the enlarger will rest, to the
wall. If possible use three right angle steel or aluminum joiners.
The attachment area of the shelf underside should be
strengthened with a narrow full width section of
board. Counter sink the attachment bolts
for a clear board area.

Attach legs at a near front location in the same manner
used to attach to the wall. Repeat all the preceding using
a shelf or shelves created by joining wall and legs.

Buy best quality FLAT board for top and shelves and
furniture or finish grade hardwood 1x4s for the two
legs. Dan

Click to expand...

Correction second paragraph: The right angle
metal attachments at the wall MAY be up or down.

Additional comments: If the wall is of some masonry or
of uneven construction an interface may be a good idea;
metal channel or solid, strong, straight , 1x4s. Attach with
lag screws or bolts. Shim those horizontals for plumb and
straight. Each shelf will need the same treatment for top
to bottom precise construction. Of course at least one
shelf is needed. I recommend that level be established
independent of floor or ceiling.

If you luck out all that's needed is top and shelving, two
legs, and attachment hardware. Dan

dancqu said:

Correction second paragraph: The right angle
metal attachments at the wall MAY be up or down.

Additional comments: If the wall is of some masonry or
of uneven construction an interface may be a good idea;
metal channel or solid, strong, straight , 1x4s. Attach with
lag screws or bolts. Shim those horizontals for plumb and
straight. Each shelf will need the same treatment for top
to bottom precise construction. Of course at least one
shelf is needed. I recommend that level be established
independent of floor or ceiling.

If you luck out all that's needed is top and shelving, two
legs, and attachment hardware. Dan

Click to expand...

Here's a simplification although likely more expensive.
At the wall use a single length of right angle steel or
aluminum for top and each shelf. Shim as suggested
in my previous post.

With large heavy enlargers I'd suggest 3/4 inch solid
core plywood; marine if possible. Shelves can be
of lighter weight. Dan