Journey to build a new darkroom - Build log

I'm starting to get back into a number of projects and have been putting off building a proper darkroom since we bought our home in Dec 2019. Now is the time! I'm gonna try to document the build along the way and figured that it could be useful to others to see my process and how it comes together (planning on posting here and the LF forum). Experience has also shown that the community here is also always a great source of feedback and ideas. I'll plan to post here periodically with updates as I make progress. There are a million ways to build a darkroom and I'm doing this with a bit of a budget in mind and with minimal advanced carpentry/plumbing/electrical/etc skills. I'm also basing my build on my own needs (which I'm sure differ from many other people) so none of it is meant to be scripture but I hope it's useful to others who may want to build their own. I'll no doubt also have questions and would appreciate your insights and wisdom. If you have ideas along the way, please share. I won't be able to incorporate everything but I'm sure there will be great ideas I haven't thought of.

Here is my first video discussing the construction of the sink which is of medium size (I'm working with limited space so couldn't do full size) and is made of lumber from your common home improvement store. The internal dimensions of the sink is 60"x25 which lets me fit two 20x24 trays when needed and more when working at smaller sizes. The sink will be epoxy sealed using West Systems two-part epoxies which are my preference when needing to get a really high quality long lasting waterproof seal like I'll need in this case:

Youtube Video - https://youtu.be/3eGZprBwoEI

When you say West-System I assume you are considering using fiberglass cloth as well? If not try to add that to it, it will make a world of difference in not only how it will last, but how it will bind it all together. One of lowest weights will do and it will be easy to smooth it out. I'd actually use two layers, but that's me.

VTLD said:

When you say West-System I assume you are considering using fiberglass cloth as well? If not try to add that to it, it will make a world of difference in not only how it will last, but how it will bind it all together. One of lowest weights will do and it will be easy to smooth it out. I'd actually use two layers, but that's me.

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I have in the past but based on building a few of these over the years I came to find that I don't really need it. Yea, it definitely ads additional strength and more material separating the wood from the surface and realistically if you're making a sink that you need to last forever, adding fiberglass is the way to go. We're planning to add on to the house eventually at which point I'll build a larger totally purpose built darkroom so at that point I'll have to build another sink anyway. Based on past experiences, I have no doubt this sink will last until then without issue. I've built a few of these without using fiberglass and a couple are still being used 15 years later with no rot and no issues at old houses I've lived at in the past. I credit the success of those just with ample coatings (4-5) of epoxy with slow hardener and doing a good job with sanding between coats to ensure that each layer bonds really well to the previous. Planning on doing the same with this one.

Here is the Part 2 video.

I used West Systems epoxy as I mentioned and it worked perfectly. Four to five coats (105 epoxy + 206 Slow Hardener) yields a thick surface that has depth and looks like a glass sheet is sitting on the wood. The 206 Slow Hardener works great as a leveling epoxy which gives you a nearly perfectly smooth surface (if you don’t use a vacuum to purge all air from the mixed epoxy, which I didn’t, you may have some tiny air bubbles but those done impede getting a very acceptable surface). I did not use a fiberglass layer for the surfaces as I mentioned but I did use fiberglass thickener (West Systems 406 Colloidal Silica filler) to thicken the epoxy for filling the corners/seams. You need that so that the epoxy doesn’t run out of the seams. I talk a bit about that in the video.

Next up is plumbing the sink. I’m not running hard lines because I may need to shift the sink around a bit from time to time. My water outlet in the room is also 4 feet up the wall (outlet for the washing machine) so I’ll be building a utility sink drain pump to move water up and out from the drain. I’m working on a video now to show how I go about that.

Best of luck with your build. I'm about to dive into a darkroom build myself. I have a darkroom in my current house but we're moving and I need to build a new one in the new house. Interestingly, your layout will be very similar to mine as I plan to build mine in a spare bathroom. I'm going to gut the entire bathroom so there won't be any dual-use issues. The physical dimensions of my room appear similar to your laundry room so I am curious how you solve some of the workflow issues that may come up. My dry end will be similar to yours over the washer/dryer and the wet side along the long wall. This left-to-right flow seems to work well in my current darkroom as I'm right handed.

Home darkrooms are nice to have, but the building of one can get too involved for me - I've done it several times in my life and some years ago after my fifth or sixth attempt to put in a permanent one, I decided "no way!" - and went minimalist.

For me the best darkrooms are built so they can be easily dismantled. Few of us stay in one place, be it an apartment or a house, for a lifetime - it's best that the darkroom can be quickly taken down and moved on if need be.

In 2020 after our move from Tasmania to mainland Australia, I rebuilt mine in our spare bedroom with panels I made from old doors and an off-the-shelf budget price folding dark window shade I found by chance in a Reject Shop. The panels are painted a mid grey and they effectively isolate an area of about 8x8 feet into my work space, which suits my way of working.

We have only one bathroom, so using it wasn't an option for me. Instead I went for our spare bedroom (one of three), which is quite a large room which we now use for multiple purposes.

I use my home darkroom every week for most of 2020 but this year I find I've printed less, about two times a month. I like to process my films the same day I actually shoot the images, so I've planned my setup to be able to do these (with a Jobo) ready to operate whenever I want.

Saving space is important to us as my spare bedroom is also used for my home office, scanning and post processing and as a sleeping area for our cats. (It's no longer used as a guest bedroom, which gave me more flexibility in planning the darkroom layout.

My LPL 7700 enlarger (I have just about every accessory made for it) sits on a kitchen trolley which can be moved around. An old dining room cabinet I found on the side of the road is ideal for storing paper, bulk chemistry and the small odd bits everyone uses in the darkroom. Mixed chemicals (I'm somewhat neurotic about these), films and paper (the latter two well wrapped, of course) go in a small fridge in the room.

The two main panels separating the actual darkroom from the rest of the bedroom are standalone but also supported by an old wood table on the bedroom side, which also holds bits of equipment (spare photo easels, a paper trimmer, I use in my processing but don't want to have cluttering up the main table in the actual work space, plus a stereo unit - and my supply of red wine for the evening as I find I enjoy an occasional sip of cab-sav to keep my creative juices flowing, along with good FM music or a jazz CD.

Piping water into a darkroom will probably be the most expensive part of your 'build' if you decide to go that way. I decided not to as i
now use a Jobo unit for film processing anyway. A large dish tray I bought cheaply (again from the Reject Shop) holds my prints which I then wash in the kitchen with a Paterson washer (occasionally) or a Kodak tray siphon (usually). If I decide to use trays for print processing I have a three-tier unit designed for kitchen use, bought at a house wear shop in Melbourne.

Your videos are excellent and I admire the planning and effort you've put into this project, but at my age and with my more casual approach to such things in life, I have to say it wouldn't suit my way of working at all. But as the French say, "a chacun son gout".

We have different ways of working, and I find the above suits me well. I hope yours will be just as useful to you, and leads to to new creativity and productive endeavors.

Thanks for the videos. I started building a sink a couple of months ago and I have yet to apply the epoxy. I thought of using the same epoxy I used on my garage floor (Rust Oleum) and then apply their Premium Clear Coating for waterproofing per their recommendation. I think the West System epoxy (or similar) is a better option. Your sink looks great.

DMJ said:

Thanks for the videos. I started building a sink a couple of months ago and I have yet to apply the epoxy. I thought of using the same epoxy I used on my garage floor (Rust Oleum) and then apply their Premium Clear Coating for waterproofing per their recommendation. I think the West System epoxy (or similar) is a better option. Your sink looks great.

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There is no contest between West System and any non-yachting related "epoxy" compounds. West System has been around for a few decades now, and has taken the ocean beating for just as long. Get it with dosing pumps, so you can make as little or as much as you need for a single batch, without even thinking of mixing ratio.

Being in Southern California, please consider putting any and all film and print washers on optional (valves) closed-loop systems with recirculating pumps to save on water. That is what I have done and I live at the headwaters of where a large portion of your water historically comes from.

The other thing I have done is put PVC pool / spa diverter valves on both of my sinks to reclaim some of the grey water that contains trace amounts of chemistry other than fixer for use in flushing, watering of trees and shrubs. Being on a septic system, fixer is strictly disposed of via evaporation then paid landfill disposal as a solid.

I believe that grass roots level advances in both effluent reduction and especially water consumption in darkroom work will become more and more critical as water scarcity becomes a more harsh reality.

Other than that, good luck in your build and have fun!

Ai Print said:

Being in Southern California, please consider putting any and all film and print washers on optional (valves) closed-loop systems with recirculating pumps to save on water. That is what I have done and I live at the headwaters of where a large portion of your water historically comes from.

The other thing I have done is put PVC pool / spa diverter valves on both of my sinks to reclaim some of the grey water that contains trace amounts of chemistry other than fixer for use in flushing, watering of trees and shrubs. Being on a septic system, fixer is strictly disposed of via evaporation then paid landfill disposal as a solid.

I believe that grass roots level advances in both effluent reduction and especially water consumption in darkroom work will become more and more critical as water scarcity becomes a more harsh reality.

Other than that, good luck in your build and have fun!

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I've got a magnet drive pump on my archival print washer. Works great. Print washers use huge amounts of water.

C-130 Nav said:

Best of luck with your build. I'm about to dive into a darkroom build myself. I have a darkroom in my current house but we're moving and I need to build a new one in the new house. Interestingly, your layout will be very similar to mine as I plan to build mine in a spare bathroom. I'm going to gut the entire bathroom so there won't be any dual-use issues. The physical dimensions of my room appear similar to your laundry room so I am curious how you solve some of the workflow issues that may come up. My dry end will be similar to yours over the washer/dryer and the wet side along the long wall. This left-to-right flow seems to work well in my current darkroom as I'm right handed.

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Yea, I'm definitely working it out as I go and having to be a bit creative. I've always had large darkrooms and this isn't optimal but it's the only space that I can use until we build onto the house at some later date. I'm also ok with modifying my methods here and there to make the space work so hopefully it all works out. Good luck with your build and definitely share some of your experiences putting it together along the way.

VTLD said:

There is no contest between West System and any non-yachting related "epoxy" compounds. West System has been around for a few decades now, and has taken the ocean beating for just as long. Get it with dosing pumps, so you can make as little or as much as you need for a single batch, without even thinking of mixing ratio.

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Yea, I've just found their products to be superior to just about anything else. And yep, the pumps are the way to go. Best idea since I've seen implemented in a system like this. Makes everything so much easier!

Ai Print said:

Being in Southern California, please consider putting any and all film and print washers on optional (valves) closed-loop systems with recirculating pumps to save on water. That is what I have done and I live at the headwaters of where a large portion of your water historically comes from.

The other thing I have done is put PVC pool / spa diverter valves on both of my sinks to reclaim some of the grey water that contains trace amounts of chemistry other than fixer for use in flushing, watering of trees and shrubs. Being on a septic system, fixer is strictly disposed of via evaporation then paid landfill disposal as a solid.

I believe that grass roots level advances in both effluent reduction and especially water consumption in darkroom work will become more and more critical as water scarcity becomes a more harsh reality.

Other than that, good luck in your build and have fun!

Click to expand...

Great points on water consumption. I am in a drought-prone location so I'm definitely planning to install some things to reduce water waste and to reclaim some of the water for use elsewhere. We just recently purchased the home so I have all kinds of water collection projects planned. Some of that will eventually be folded into future darkroom plans especially when it comes to print washers etc.

Here is a short video discussing my plans for sink ventilation.

Here is another update with videos. I had a chance this morning to upload a couple of videos that I've been putting together to talk about the blower I've chosen to use for the ventilation system. I've gone with the Dayton 1TDU2 which is 1202 CFM and has good reviews. I originally picked a much smaller blower (based on misunderstanding some data) and had to upgrade when I discovered the problem.

This video discuses my plan for how I'll set up the blower with ventilation cones to reduce the intake to 4-inch standard drying tube size, and then further to 2-inch and to sink for optimal suction. Reducing the intake also provides air flow restriction which helps to ensure that the blower motor doesn't free spin and burn out.

And this video is a step-by-step guide for how to wire the Dayton 1TDU2 blower to a power cord for 120 voltage (it's also possible to wire it for 220). I also show a moment where the blower surprised me and I almost lost some fingertips. Safety first!

Fragomeni said:

Here is another update with videos. I had a chance this morning to upload a couple of videos that I've been putting together to talk about the blower I've chosen to use for the ventilation system. I've gone with the Dayton 1TDU2 which is 1202 CFM and has good reviews. I originally picked a much smaller blower (based on misunderstanding some data) and had to upgrade when I discovered the problem.

This video discuses my plan for how I'll set up the blower with ventilation cones to reduce the intake to 4-inch standard drying tube size, and then further to 2-inch and to sink for optimal suction. Reducing the intake also provides air flow restriction which helps to ensure that the blower motor doesn't free spin and burn out.

And this video is a step-by-step guide for how to wire the Dayton 1TDU2 blower to a power cord for 120 voltage (it's also possible to wire it for 220). I also show a moment where the blower surprised me and I almost lost some fingertips. Safety first!

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Set up ventilation to create negative pressure in the darkroom. Let dust get going on a trajectory towards outlet.

VTLD said:

Set up ventilation to create negative pressure in the darkroom. Let dust get going on a trajectory towards outlet.

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I think you mean positive pressure (ie the darkroom is at a higher pressure than outside), so that any dust etc in the darkroom is forced out through the ventilation. Negative pressure will draw in air and dust from the outside.

Mark77 said:

I think you mean positive pressure (ie the darkroom is at a higher pressure than outside), so that any dust etc in the darkroom is forced out through the ventilation. Negative pressure will draw in air and dust from the outside.

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No, I meant negative. Positive accelerates dust movement around space, negative draws it out, it's a fundamental difference, not the same thing.

VTLD said:

No, I meant negative. Positive accelerates dust movement around space, negative draws it out, it's a fundamental difference, not the same thing.

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Agree to disagree. As this article points out, both options have pluses and minuses. https://lensnotes.com/darkroom/ventilation/. Given some of the chemicals used in darkroom processing, I prefer that the ambient pressure removes this air and replaces it with fresh from outdoors.

Mark77 said:

Agree to disagree. As this article points out, both options have pluses and minuses. https://lensnotes.com/darkroom/ventilation/. Given some of the chemicals used in darkroom processing, I prefer that the ambient pressure removes this air and replaces it with fresh from outdoors.

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I'm not going to read an article on a principle I've been directly involved with. Negative pressure in a space creates completely different air flow pattern to one forced in by positive pressure. This is an exhaust fan drawing air out and inlet allowing air in (in larger spaces and higher fume creation both, supply and exhaust fan are usually needed). For typical small darkroom space, all is needed is variable intake filtered louver and an exhaust fan (preferably variable speed too). Both variables make it easy to make proper adjustments to get the right pattern.

One needs to see dust movement in both set ups to see the difference, which is difficult to picture without that visual. But possible to simulate in a dark space with proper lighting and dust introduced as fans are running in different mode. But I did not bring it up to argue it over. Whoever wants to give it a try, it's their choice.

I think there is a chance that the two of you are actually describing the same set-up, but applying the negative pressure and positive pressure labels in very slightly different ways.
You want the ventilation to be set up so it sucks out air from the darkroom.

We don't need to have a debate on the semantics of negative and positive pressure. The article Mark linked is a good one and describes them both well. Both have pros and cons and both achieve similar effective ends when implemented properly in an otherwise sealed room. Anyone installing something like this just needs to decide which route they want to go. In my case, I'm using a negative pressure setup (just using that term based on how I understand it's used) wherein I have my blower exhausting air from the room and I'll have a light tight louvered filtered vent which will allow air to be pulled into the room from outside via the negative pressure created by the blower sucking air out of the room. That's the type of system I've used before and it works well for me so I've planned around that.

On that note, can anyone recommend a good louver vent with a space for a filter? I've been looking at this Doran louver vent from B&H but I don't think it's filtered. I can build a filter box for it if necessary but would ideally prefer a system already set up with one. Recommendations would be appreciated if anyone has any.

Here is a video update on the sink-level ventilation and why I changed my plans away from the pipe with the holes running the length of the sink. I finished setting up the ventilation blower and hooked it up to the sink ventilation that I was planning to use but found that even with a 1202 CFM blower, the pipe with holes running the length of the sink wasn't effective at removing fumes/vapor (I did a smoke test using incense). I ended up deciding to remove the pipe and switch to a movable point-source solution with a mini hood which works much better and achieves the goal of moving air (and fumes) across the surface of the sink to the blower without allowing it to travel up to face level. The video discusses my tests and the change of plans as well as shows the difference in effectiveness between the two methods.

Here’s a quick pic of the water filtration system set up and running like a charm. I’ll post a video with progress updates soon showing how it all works. I have hot and cold water running through their own dedicated filters. I used KleenWater filters which are well reviewed. They make various purpose build home water filtration systems including a filter specifically for hot water which is key. I’ve seen in a lot of people’s setups folks running hot and cold water through standard whole home water filters but most of those filters are designed for filtering cold water up to a low max temp coming straight off your main water line. Running hot water through those filters will prematurely degrade the filter insert and the casing materials and seals risk rupture because they’re not designed for higher temps. The KleenWater hot water filter is made of a stronger composite material designed to withstand higher water temps coming out of a hot water heater and they use dedicated filters also designed for higher temps.

I have both filters coming off of splitters attached to the hot and cold water sources for our washing machine. Dedicated lines run to each with valves on both the input and output sides of the filters as safety shut-offs. Each then runs to the faucet at the sink.

I’ve not set myself up to have to instal another set for the main house because my wife wasn’t as amused as I was that the darkroom has the highest quality water in the whole house

I have a portable sink and have used bottom epoxy paint for the sink. It works just fine and I just sand and repaint every few years...not complicated at all

Peter Schrager said:

I have a portable sink and have used bottom epoxy paint for the sink. It works just fine and I just sand and repaint every few years...not complicated at all

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Epoxy paint can work great if you’re cool with dealing with sanding and repainting over the long term. Not at all too much of a task for most folks. I’m lazy though and like to just do a job once and be done with it. Epoxy resin is the go to for that. As long as it’s kept clean and you’re not using heavy corrosives frequently, a triple or quadruple coated sink like this will last decades without needing any refinishing. That’s why it’s my go-to. The coating process is probably a little more work compared to just painting but that’s out of the way once it’s done. Fair trade in my book.

It's taken me a little while to make a video updating showing how the finished darkroom came together. I'll be making little updates to the setup along the way as needed but overall it's done and came out great. Here is a quick video tour of the finished space.