Darkroom ventilation?

kr236rk · Sep 24, 2022

Hi,

Hey, there are new filmstocks!

I still have a darkroom-blind bathroom, but no ventilation.

So I just have to put in some DIY ventilation fans, to get my darkroom up & running again

- to take advantage of the new filmstocks!

Who would have thought that 'wet' processing was on the come-back?

Any ideas for ventilation would be very welcome - thank you!

KR

snusmumriken · Sep 24, 2022

I didn't want a fan pumping dust and pollen into my darkroom, so I bought two 4-inch fans with filters from RS-components and installed them as inward and outward flow. 4-inch ducts are easily found. Made light baffles to fit over them out of plywood, attached with magnets to allow filters to be changed. Works perfectly. I can take photos if you are interested.

AgX · Sep 24, 2022

What sort of filters do you use?

Is your inward flow coming from the true outside or from the rest of the appartment/house?
Speaking of pollen, it likely is the former, what means having cold air flowing-in in the winter.

snusmumriken · Sep 24, 2022

AgX said:
What sort of filters do you use?

Is your inward flow coming from the true outside or from the rest of the appartment/house?
Speaking of pollen, it likely is the former, what means having cold air flowing-in in the winter.

Yes, ventilating from/to outside. In practice, I don't need the fans running during printing sessions. I tend to put them on when I take a break. Yes, they do cool the room a little, but I have a room heater (electric oil-filled convection heater).

I think these were the fans and filters I used. Or something very similar. There are so many varieties you have to study the specs closely to match your needs.
https://uk.rs-online.com/web/p/axial-fans/1018052
https://uk.rs-online.com/web/p/fan-filters/0221342

AgX · Sep 24, 2022

And what openings to the outer world did you use/make in your DIY approach? Long time a round cutout in a window pane was used. This was rather cheap to make and to redo if necessary. In times of thermopane windows this approach has gone. Remains a insert into the slit of a partially opened window. Or a core drilling through a wall (european walls from bricks).
Any more approaches?

snusmumriken · Sep 24, 2022

AgX said:
And what openings to the outer world did you use/make in your DIY approach? Long time a round cutout in a window pane was used. This was rather cheap to make and to redo if necessary. In times of thermopane windows this approach has gone. Remains a insert into the slit of a partially opened window. Or a core drilling through a wall (european walls from bricks).
Any more approaches?

I used a 4-in (10cm) plastic pipe, but telescopic ducts in the same size can be found at builders' suppliers. My darkroom is a free-standing insulated wooden shed, so cutting holes in the wall was relatively easy. For masonry/brickwork, core-cutters suited to this size of duct are widely available - I have used one to install more conventional bathroom extractor fans, for instance.

AgX · Sep 24, 2022

Over here a great lot of people live in a rented appartment, core-drilling thus is not the first idea they get, and likely will not be possible.

Let's see wha the OP thinks of cutting holes.

kr236rk · Sep 24, 2022

snusmumriken said:
I didn't want a fan pumping dust and pollen into my darkroom, so I bought two 4-inch fans with filters from RS-components and installed them as inward and outward flow. 4-inch ducts are easily found. Made light baffles to fit over them out of plywood, attached with magnets to allow filters to be changed. Works perfectly. I can take photos if you are interested.

Filters sounds like a good idea, thank you

kr236rk · Sep 24, 2022

AgX said:
Over here a great lot of people live in a rented appartment, core-drilling thus is not the first idea they get, and likely will not be possible.

Let's see wha the OP thinks of cutting holes.

Can't be done - this is why it's taken me so long to set up a 2nd bathroom darkroom. The property is filled cavity-walling, no niches, nothing.

I plan to suspend a deep insect net baffle over the top-light / vent window, such that I can open the vent at night, & allow the passage of air.

However, there would be no through-flow, so I will need twin fans at the vent, pointing in opposite directions, one drawing air out, the other drawing air in.

Inside the window is a double blackout screen - 2 screen-blinds on rollers - there's just room to fiddle some piping in around the screen housing, it won't be easy, but it's possible.

I have used this room for processing in the past, but with chemicals in containers, so limited chemicals in the air. But if I get to the stage of using trays again, I will need ventilation of some description.

Property not designed for darkroom photography; there are zero extractor fans, so plenty of room for condensation. The builders did not create spaces anywhere for extra ventilation either. Place is pretty much sealed. Still, I must work with what I have.

Thanks

kr236rk · Sep 24, 2022

snusmumriken said:
I used a 4-in (10cm) plastic pipe, but telescopic ducts in the same size can be found at builders' suppliers. My darkroom is a free-standing insulated wooden shed, so cutting holes in the wall was relatively easy. For masonry/brickwork, core-cutters suited to this size of duct are widely available - I have used one to install more conventional bathroom extractor fans, for instance.

Thanks - no - I will not be cutting holes in cavity walls. I considered builders, but that's a can of worms I'd rather not open. I used to live in the city but am now in the countryside, we have billions of ants, biting spiders, clouds of mosquitoes - I have sealed off most points that these critters have got in by, in the past; it's a battle with ants every summer, I am winning.

The ants would simply love me to cut holes in the walls - their ambition is to colonise the cavity walling, but not on my watch!

Thanks again!

Sirius Glass · Sep 24, 2022

Having ventilation in the darkroom is important. How you solve that issue is up to you.

kr236rk · Sep 24, 2022

AgX said:
And what openings to the outer world did you use/make in your DIY approach? Long time a round cutout in a window pane was used. This was rather cheap to make and to redo if necessary. In times of thermopane windows this approach has gone. Remains a insert into the slit of a partially opened window. Or a core drilling through a wall (european walls from bricks).
Any more approaches?

Thought of that too - but it's sealed double glazing, an entirely new window pane unit would have to be found - the property is 40+ years old, I doubt if the window fittings still exist in exactly the same format as what is here now - I would love ducts in windows, but I've never seen that in double glazing?

kr236rk · Sep 24, 2022

Sirius Glass said:
Having ventilation in the darkroom is important. How you solve that issue is up to you.

I've always had some form of ventilation in the darkroom.

wiltw · Sep 24, 2022

If you have a sash window (slides open) you can create a custom sized unit to fit within the opening...

Foam around the 4 sides of the insert, along with a bezel which is larger than the opening of the window, help to provide a barrier to light entry. In the illustration, the circle represents an exhaust fan, and the colored parallelogram represents a rigigdsided filter...and the back size of the box (exterior surface) also has openings for air (be sure to separate the box so that air from exhaust fan does not mix with intake air coming in thru the filter side). Cord with in-line switch from fan plugs into AC wall outlet for power. Designed appropriately the interior of the box provides a maze which permits airflow without light having a straight line path into the room. This could be made from wood, or even 1/4 light-blocking acrylic plastic.

More problematic are windows that extend inward/outward when they are open. I have no generalized solution for such windows....case by case solution is necessary.

As for the fan being exhaust or pushing air into the room, the advantage of pushing filtered air into the room is that the room itself has some positive pressure so that dust is not pulled into the room when a door is opened.

When I was an apartment dweller, I had space in one room for enlarging, and transported exposed paper in Jobo tanks to the Jobo processor, which was set on a custom sized table in the bathtub...the bathroom fan took care of ventillation and I did not worry about dust.

Pieter12 · Sep 24, 2022

I have limited venting in my garage darkroom. There is an exhaust fan over the bench I use for preparing chemicals and I leave the large garage door open. For film processing, all except loading is done in daylight, so the door is open then, too. I use a vertical slot processor for prints so there is limited chemistry contact with the air. I have yet to experience any strong odors or adverse effects.

AgX · Sep 24, 2022

wiltw said:
If you have a sash window (slides open) you can create a custom sized unit to fit within the opening...

I considered such for european windows, where it becomes a more difficult task, as it needs to be a wedge shaped insert, which in addition must keep the wing of the window closed and thus cannot just be pushed into the window frame.

RalphLambrecht · Sep 24, 2022

kr236rk said:
Hi,

Hey, there are new filmstocks!

I still have a darkroom-blind bathroom, but no ventilation.

So I just have to put in some DIY ventilation fans, to get my darkroom up & running again

- to take advantage of the new filmstocks!

Who would have thought that 'wet' processing was on the come-back?

Any ideas for ventilation would be very welcome - thank you!

KR

here is my setup

tomatojoe · Sep 24, 2022

kr236rk said:
Hi,

Hey, there are new filmstocks!

I still have a darkroom-blind bathroom, but no ventilation.

So I just have to put in some DIY ventilation fans, to get my darkroom up & running again

- to take advantage of the new filmstocks!

Who would have thought that 'wet' processing was on the come-back?

Any ideas for ventilation would be very welcome - thank you!

KR

hi kr236rk

ventilation is good. there are only 3 solutions.
ceiling fan and exhaust outside,
window fan and exhaust outside
door fan and exhaust inside
window fan seems like an easy option.

AgX · Sep 24, 2022

Tomatojoe, you only have it about one flow, but for any ventilation flow you need a contrary flow. Thus a flow to the outside needs a flow to the inside.

Either achieved by two ducts to the outside, they even may share one hole, or one duct to the outside, the other, for the inflow, to the inner of the house. But then there must be enough leakage at the windows our outside doors too, which in elder houses will be a much lesser issue, than in a modern house having passed a leakage test.

Maris · Sep 24, 2022

For my third and best darkroom I insisted on no ventilation but air conditioning instead. The climate here in Noosa, Australia is sub-tropical and the darkroom can be too hot to work in for half the year. An extractor fan would pull expensive conditioned air out faster than the 2.5kw air-con can temper the fresh stuff coming in. Net result is electricity consumed but temperature control lost.

I've no direct experience of this but the cold climate answer to a comfortable darkroom is a reverse cycle air conditioner in heating mode. This is the most energy efficient way to heat a room. Again an air extraction system can defeat the heater and the room goes cold.

What about the fumes? By far the worst smell in my B&W darkroom was acetic acid stop bath so I've eliminated it; won't have it in the place. I use Fotospeed SB50 Odorless stop bath but there are other brands. That's one problem solved.

What about fixer? Acid fixer tends to give off sulfur dioxide, phew. Alkaline fixer tends to give off ammonia, phew. I use Fotospeed FX30 Odorless fixer which is strongly buffered to neutral: no SO2, no NH3.
Another problem solved.

The developers I use, mainly Dektol and Xtol, have negligible smell and the volatile they emit is water vapour; not a problem.

When I'm not running the air-con and I want a change of air in the darkroom I just open the door and go out for a walk. Works well, costs nothing.

gone · Sep 24, 2022

I've never had to vent one, probably because I've always printed in bedrooms or kitchens. Those are big spaces, and the chemistry smells are very faint in a big space.

halfaman · Sep 25, 2022

After COVID-19 going down there are a lot of air purifiers in the second hand market. I bought a Rowenta PU4020 with HEPA+carbon active+cold catalyst fillters for 80€, including a spare of each filter. It is portable requiring no installation and for rooms up to 60m2, my darkroom has 22m2.

AgX · Sep 25, 2022

Maris had it about substituting irritating fumes. A way to reduce fumes is slit- instead of tray-processing, grossly reducing the air-contact area of baths.

kr236rk · Sep 25, 2022

wiltw said:
If you have a sash window (slides open) you can create a custom sized unit to fit within the opening...

Foam around the 4 sides of the insert, along with a bezel which is larger than the opening of the window, help to provide a barrier to light entry. In the illustration, the circle represents an exhaust fan, and the colored parallelogram represents a rigigdsided filter...and the back size of the box (exterior surface) also has openings for air (be sure to separate the box so that air from exhaust fan does not mix with intake air coming in thru the filter side). Cord with in-line switch from fan plugs into AC wall outlet for power. Designed appropriately the interior of the box provides a maze which permits airflow without light having a straight line path into the room. This could be made from wood, or even 1/4 light-blocking acrylic plastic.

More problematic are windows that extend inward/outward when they are open. I have no generalized solution for such windows....case by case solution is necessary.

As for the fan being exhaust or pushing air into the room, the advantage of pushing filtered air into the room is that the room itself has some positive pressure so that dust is not pulled into the room when a door is opened.

When I was an apartment dweller, I had space in one room for enlarging, and transported exposed paper in Jobo tanks to the Jobo processor, which was set on a custom sized table in the bathtub...the bathroom fan took care of ventillation and I did not worry about dust.

kr236rk · Sep 25, 2022

Many thanks for this.

Here is the story so far - in pictures.

Here's the rough plan plus actual vent window, you will see that it has a deep recess, that is going to be very useful, because the fan unit will rest on it.

Secondly the light-proof blinds already in position plus light-trap guttering. The huge challenge here will be to coax piping into the guttering to facilitate air taken in, and extracted from the darkroom. It will be literally a tight fit, but I think I can do it.

Darkroom ventilation?

kr236rk

snusmumriken

AgX

snusmumriken

AgX

snusmumriken

AgX

kr236rk

kr236rk

kr236rk

Sirius Glass

kr236rk

kr236rk

wiltw

Pieter12

AgX

RalphLambrecht

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