Ventilation for closet darkroom

Hello everyone!

I got back into film photography and I absolutely love it. One of my favourite past time was to go to the dark room, spend a few hours and do some printing. Because of the digital age, there aren't any places really in my town where I can do that so I decided to convert my empty and never used walk-in closet into my very own darkroom. It wouldn't be anything fancy, just the bare minimum so an enlarger and the chemicals. I would use it maybe once per week for a few hours, just as a past time. it is a pretty small closet (185 feet cubed) and has no windows so one thing that has me worried is the potential health risks with the chemicals.

If I do ventilate the room the way it's been suggested online, I'd have to attach a fan above my wet side and have a 25 feet long duct going along the side of my bedroom all the way to the nearest window. It wouldn't be the prettiest thing as I'd have an ugly grey duct running through my room so I'd like to find an alternative. I have a few options;

1- Since I wouldn't use it often, I'm wondering if I could simply forget about ventilation and let the room breathe when it's not in use? Some people believe that chemicals aren't harmful and as dangerous as regular household cleaning supplies while others say that they can cause nervous system damage. I'm not sure which is the case which is why I'm hesitating with that option.

2- If that solution doesn't work, could I just have the air from the darkroom get sucked out into my larger bedroom where the "bad air" would get diluted and the home ventilation system can take care of it? that would eliminate the need for the duct to go through my room and out the window but I'm unsure if it would really work or if it is safe.

3- Last option would be to use an air purifier instead of a ventilation system that could filter out the chemicals while I'm using the room. that would be ideal since no extra work would be needed and be much neater but again I'm not sure if it safe

If anyone has some darkroom experience or has built one themselves, please let me know what the best option is. Any tips or suggestions are appreciated.

Thank you for your help!

If you use Citric acid stop bath and low odor fixer, (Ilfostop, Ilford rapid fixer) you might not be bothered. No Selenium toner in there without leaving the door open.

The biggest offenders are Acetic acid stop and the regular Kodak F-5 powdered fixer. Those will not kill you but are miserable to work with. Most developers don't smell much.

Welcome to Photrio.
What processes are you planning to do?
If you are planning to develop and print black and white film, then the most commonly used chemicals aren't particularly problematic. You need air flow, but you would need air flow even if you weren't using chemicals in your closet.

MattKing said:

Welcome to Photrio.
What processes are you planning to do?
If you are planning to develop and print black and white film, then the most commonly used chemicals aren't particularly problematic. You need air flow, but you would need air flow even if you weren't using chemicals in your closet.

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Yes I would just print black and while. I would only scan my colour negatives

As for airflow, I will probably have a small lightproof fan that allows air from the outside to get an and one for the inside air to get out as long as the inside air isn't damaging to my bedroom

mshchem said:

If you use Citric acid stop bath and low odor fixer, (Ilfostop, Ilford rapid fixer) you might not be bothered. No Selenium toner in there without leaving the door open.

The biggest offenders are Acetic acid stop and the regular Kodak F-5 powdered fixer. Those will not kill you but are miserable to work with. Most developers don't smell much.

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I would be using the ones you mentioned and I wouldn't use a toner either

do you think that an air purifier would be necessary at all?

I convert my bathroom for darkroom use, so that means I do have the benefit of a bathroom ventilation fan, but even if I didn't all I would really need to do is open the door regularly.
The inside air won't damage your bedroom. If you share your premises, others may not like the faint odour, but maybe they'll be fine with it. The fumes from standard darkroom chemicals aren't really of much concern. Acetic acid based stop baths are a bit strong, but the others aren't really a problem.
I do prefer to mix up the chemicals in a bigger room, with an open window, but that is because that is where I have the best light and easily adjusted water temperature.
Colour chemicals are of more concern, but there are solutions for them as well.
Of greater concern is:
1) chemical spills - don't spill chemicals on furniture or carpets - it can be extremely hard to clean and, if allowed to dry, the dust from things like fixer isn't particularly good for you;
2) extensive chemical to skin contact. There are people out there (myself included, although not so much now) who have been putting their hands into darkroom chemicals for decades and have shown no ill effects, but allergy like sensitivity is a real possibility, and contact dermatitis is something you want to avoid. Gloves and/or tongs are recommended.

AndreSaulnier said:

I would be using the ones you mentioned and I wouldn't use a toner either

do you think that an air purifier would be necessary at all?

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The air purifier depends on how it works. If there is a activated carbon component that will remove odor. Might be useful to keep in the bedroom?

If the entrance to the closet is dark enough at night with the lights off, you could leave the door open.

Otherwise, I'd go for option 3. Get a carbon filter and matching fan from a hydroponic store and duct tape them together. Can be hung from the ceiling using rope ratchets. Overkill for your purpose but the filter should last many years. I'm thinking of setting one up mainly for dust removal.

I don't have any issue at the time when working with photo chemistry in a smaller space, but I do notice that I'm prone to mildly annoying headaches the evening after. Good air flow seems sensible, and I'm exploring the idea of building a 'darkroom box' that I can set up on my deck and just stick my hands inside to work with.

If you have hollow core doors, then they are relatively easy to split open to convert to a light trap vent. (suggest taking the BACK side off, not the front side facing outside the closet, so that if you do happen to screw up and break something you can at least hide it behind a closed door.)

With the back side off, clean up the core, and install baffles of suitable material, such as cut lengths of 1x1 planed down as needed or even just folded card stock "I-beams", so that the air takes a snaking path back and forth. (Just remember to make sure you double check internal spacing so you don't accidentally leave a light gap when you glue the panel back on.) Spray paint black, and install a tasteful looking grill or louver on the front as needed.

Split it into two zones to handle in and out, and install a fan to get the air moving. Would suggest avoid putting an intake that gets too low to the ground to avoid kicking up dust. Maybe add covers so you can close the vents off completely to keep the door itself from gathering dust inside between uses.

Add weather stripping to seal the gaps as needed, and save needing to deal with drywall dust from putting a vent through a wall.

Also adds a layer of protection against someone accidentally switching the bedroom/hall/whatever lights on while still getting good air exchange in the space.

I temporarily convert my bathroom and one bedroom into a darkroom. The bathroom has an exhaust fan for ventilation and I use that room for chemical in trays for prints. The bedroom has the enlarger and print dryer and does not require ventilation. I use a darkroom bag https://www.freestylephoto.biz/25001-Photoflex-Changing-Room to load film into daylight tanks and I develop the film in the kitchen in light where I can open a window.

I think solution # 2 would be adequate. If you are in a single-storey house you could vent into the attic.

Visit a HVAC shop or hardware store nearby and investigate some flexible ducting and a duct fan that can be temporarily routed out a nearby window. You might have to build a light trap for the unit, which is a simple box with duct connectors on each end and an "S" baffle painted black on the interior to avoid light ingress. You could get so fancy as to put a duct register boot on the flexible duct and make an evacuation scoop near your trays or work area to draw out the fumes. Just be sure you have an ingress for fresh air that is light-tight...

I've used a walk in closet and a pantry similar in size. Never had any problem so option #2 is what I've used but if you want to be on the safe side
use the air cleaner.

John51 said:

If the entrance to the closet is dark enough at night with the lights off, you could leave the door open.

Otherwise, I'd go for option 3. Get a carbon filter and matching fan from a hydroponic store and duct tape them together. Can be hung from the ceiling using rope ratchets. Overkill for your purpose but the filter should last many years. I'm thinking of setting one up mainly for dust removal.

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i will probably use a blackout curtain because the door has a lot of light leak and it would be easier to run fans through

would a regular air purifier be enough for my purpose? something that i can easily plug in an outlet that has an HEPA and activated carbon filter like this unit https://www.amazon.ca/gp/product/B071D58ZY5/

im trying to keep my expenses down and the setup as simple as i can

One thing to take into consideration is where the fresh air will be coming in and where the old air will be vented out. Avoid, if possible, having the fumes from the trays rising up past your head on their way out. That could be worse than no ventilation. It would be much better if your head was in the pathway of the fresh air coming in.

I have no ventilation where I tray develop 11x14 film. I am using a water stop and I keep the fixer tray covered unless I have film in it (and can even keep it covered while agitating the fix). I can vent the room after every negative to prevent a build-up of fumes.

John Koehrer said:

I've used a walk in closet and a pantry similar in size. Never had any problem so option #2 is what I've used but if you want to be on the safe side
use the air cleaner.

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when you did that did you also have a fan to flow fresh air in?

Vaughn said:

One thing to take into consideration is where the fresh air will be coming in and where the old air will be vented out. Avoid, if possible, having the fumes from the trays rising up past your head on their way out. That could be worse than no ventilation. It would be much better if your head was in the pathway of the fresh air coming in.

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could an air purifier take care of the fumes? then I could circulate fresh air from the bedroom using a set of fans

Treat the air purifyier as the intake of clean air coming into the room. If your head is above the trays, and the fumes rise up past your face before they go thru the purifyier, then the purifier will keep the fumes from building up, but you will still be breathing in the fumes directly.

And that is if a air purifyier can actually handle the job efficiently and the cost effectively.

edited to add -- dang I need to read other replies first! I could have just wrote, 'ditto that". I do not know the capacities of air cleaners.

I work in a darkroom that is a converted bedroom. I only do B&W printing now but have done RA4 colour. In warmer weather when the room is not in use as a darkroom I open the window but this is to try and cool the place rather than ventilation. As others have said, the chemicals are in my opinion, relatively harmless. At the end of a printing session it makes sense to drain the trays and either dump the chemicals or decant back into containers. My converted darkroom when not in use, has a door that's left open and it is next to our bedroom. What fumes there are, are vented into the upstairs landing/ our bedroom and I have yet to notice any fume/smell influx into our bedroom. However I need to add I use a Nova slot processor which has very small air exposure compared to trays

If you have the money and can obtain a Nova slot processor then I would get one. It saves space and the chemicals can be stored in it permanently so has a large convenience factor but if you cannot obtain a Nova or lack the money then use trays and see how you feel after a session of say 2-3 hours.

If you feel OK then that's fine. If you "suffer" the next day then you may have to consider either a Nova, ventilation/filter or shorter sessions but the good news is that unless you belong to a very small percentage of the population that may be seriously adversely affected by developer, stop and/or fixer I do not think your health will suffer even if you do not like the smells.

pentaxuser

Vaughn said:

I can vent the room after every negative to prevent a build-up of fumes.

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Where do you vent to? do you simply open a door to let the air go to a different room?

if that is the case then I believe that this would be my best option since I will be using the same chemical setup as you

pentaxuser said:

I work in a darkroom that is a converted bedroom. I only do B&W printing now but have done RA4 colour. In warmer weather when the room is not in use as a darkroom I open the window but this is to try and cool the place rather than ventilation. As others have said, the chemicals are in my opinion, relatively harmless. At the end of a printing session it makes sense to drain the trays and either dump the chemicals or decant back into containers. My converted darkroom when not in use, has a door that's left open and it is next to our bedroom. What fumes there are, are vented into the upstairs landing/ our bedroom and I have yet to notice any fume/smell influx into our bedroom. However I need to add I use a Nova slot processor which has very small air exposure compared to trays

If you have the money and can obtain a Nova slot processor then I would get one. It saves space and the chemicals can be stored in it permanently so has a large convenience factor but if you cannot obtain a Nova or lack the money then use trays and see how you feel after a session of say 2-3 hours.

If you feel OK then that's fine. If you "suffer" the next day then you may have to consider either a Nova, ventilation/filter or shorter sessions but the good news is that unless you belong to a very small percentage of the population that may be seriously adversely affected by developer, stop and/or fixer I do not think your health will suffer even if you do not like the smells.

pentaxuser

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unfortunately, the Nova system is too expensive. i am trying to keep my cost below 250$ and all the equipment from BH photography store already cost me 100$

I do have previous experience in a darkroom and would spend hours at a time there but never did I feel light headed from the chemicals. if you say that airing out the air to the larger room will be enough then i think i will just go with that option

Like as not, if you suffer from headaches the next day it isn't the fumes from the chemicals that cause the problem, but rather spending several hours in a warm and humid and stuffy small room without ventilation.
The oxygen you breathe and use up and the carbon dioxide you exhale are probably the biggest culprits.

MattKing said:

Like as not, if you suffer from headaches the next day it isn't the fumes from the chemicals that cause the problem, but rather spending several hours in a warm and humid and stuffy small room without ventilation.
The oxygen you breathe and use up and the carbon dioxide you exhale are probably the biggest culprits.

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fair point. I believe that I will mostly focus on having good air circulation and not worry too much about the chemicals. might get a purifier just to be extra safe

A purifier may be designed to be most effective with a particular set of air contaminants. It might be difficult to find one that is matched to the mostly inorganic (IIRC) fumes from a black and white darkroom printing session.

MattKing said:

A purifier may be designed to be most effective with a particular set of air contaminants. It might be difficult to find one that is matched to the mostly inorganic (IIRC) fumes from a black and white darkroom printing session.

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from what I'm reading online, an activated carbon filter should do the job. also as others mentioned, the chemicals aren't too dangerous so this would really just be to be extra cautious