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MOPS
08-09-2009, 04:58 PM
Anybody know how to make an air baffle for a darkroom? I have just built a shed and intend to use it as a darkroom. Tim Rudman has details of how in one of his books but it is not detailed enough. Help please before I suffocate!:confused:

archphoto
08-09-2009, 05:48 PM
An air baffle is an opening where the air has to go around corners in order to enter a room.

For darkroom purposes it is painted flat black on the inside in order to avoid reflexions.

If you PM me your email adres I can send you some disigns.

Peter

mgb74
08-09-2009, 05:51 PM
Is the baffle intended to be placed within the cavity of a stud wall or as a vent pipe to the outside?

Mike Wilde
08-10-2009, 11:24 AM
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Make everywhere there is a round bracket painted black. It can be a section of pipe with elbows at the end. or a void space within a wall cavity.

Monophoto
08-10-2009, 11:44 AM
A light baffle is simply an opening through a box (which could be a wall cavity) that allows air flow but that prevents light from coming through.

The basic principle of a light baffle is that light (and we won't get into the hoary old argument of whether light is a ray or a particle) follows straight lines - except when it reflects or refracts. Light baffles don't involve glass, so we don't have to worry about refraction.

The sketch illustrates what the cross-section of a light baffle might look like. Note that it's simply a couple of barriers that keep the light entering one hole from passing straight through to the other hole. The interior of the baffle is painted flat black to prevent light from entering one hole and bouncing around the baffles to exit the second hole.

Francis in VT
08-10-2009, 12:19 PM
If the baffle is to be constructed in a stud wall the openings should be made to accept a standard size air filter. For example in a 16" stud wall you could use a 16" X 8" X 1" filter.
Go with what is readily available.

Francis in VT

pentaxuser
08-10-2009, 01:32 PM
Anybody know how to make an air baffle for a darkroom? I have just built a shed and intend to use it as a darkroom. Tim Rudman has details of how in one of his books but it is not detailed enough. Help please before I suffocate!:confused:

Are you referring to P13 of his Master Printing Course book? It looks fairly straightforward. The baffle has to be slightly bigger than the extractor vent on the outside wall of the shed. Essentially its a box with 6 sides. A top side and front side screwed together to form a right angle. A smaller bottom side and front side screwed together so the bottom front side fits inside the top front side. Finally two sides close the "box" completely.The more the two front side overlap the better the chance that light can't get round the corners. In fact as long as there's even a small gap air will get out. All sides need to be painted matt black and I'd seal the edges as well where each side screws to any other with a waterproof sealant.

At the college where I went on a darkroom course the same baffle arrangement was constructed in the passageway between the darkroom and the white light room and was big enough to allow the movement of one person at a time. If that worked and it did, the much great overlap in the T Rudman illustration will certainly prevent any light penetration.

If you use an extractor fan then you'll need a simple vent( in effect a square hole) in the door as well with similar baffles. If you suck air out then air has to get in to replace it.

pentaxuser

MOPS
08-10-2009, 04:35 PM
Thank you one and all, I get the idea, since I made the shed from scratch I should be able to make one of these! Pentaxuser, thank you for the detailed descriptions. Louie, thanks for the details.......MOPS

RalphLambrecht
08-10-2009, 04:59 PM
Anybody know how to make an air baffle for a darkroom? I have just built a shed and intend to use it as a darkroom. Tim Rudman has details of how in one of his books but it is not detailed enough. Help please before I suffocate!:confused:

This is how I made mine (shown in a cut-away).

MOPS
08-12-2009, 04:30 PM
Thanks for the picture of the baffle Ralph, I now have the thing in mind and will give it a go.....MOPS

monosnaps
08-13-2009, 03:57 PM
Lots of helpful advice there Brian to get you started.

OldBikerPete
08-14-2009, 08:04 PM
Others on this thread have outlined the general principles. May I suggest you get hold of an old louvre door or two and orient them on opposing sides of a stud wall so that a direct light ray cannot pass. Blackboard (chalkboard) paint is a good light absorber.