Suitable location for a Darkroom

Darkness

For a darkroom, you need a room that can be perfectly darkened. Light must not be allowed to penetrate either through the windows or through any cracks in the door. Check this by sitting in the completely dark room for five minutes in bright outside light. If you still do not notice any glimmer of light, the room is sufficiently darkened. If light still penetrates through any cracks, a curtain made of dense black fabric will help.  

Water and Electricity

Ideally the laboratory is heatable, can maintain a constant temperature, and has both electricity and water. For black and white work, cold running water will suffice; for color work, you will definitely need warm water. If you have a mixer tap that allows you to control the temperature of the running water precisely and constantly, you have the best you can hope for.
Of course, with the water connection you need a basin. In a pinch, a small, simple sink will do, which will allow you to throw away solutions, drain the water. Much more practical is a sink, as used in kitchens a basin made of stainless steel with a worktop attached to the side.  

Ventilation

The laboratory should be well ventilated, esp. if you are working with color-chemistry. In some cases, you will be working at relatively high temperatures of up to 40° C with chemical baths that evaporate naturally. The air in your darkroom quickly becomes saturated with moisture. And this moisture condenses on everything in the lab.
Especially when the temperature drops after the work is finished and the air can no longer hold the humidity. This is not good for the equipment, chemicals or papers. Metals rust or corrode, and a milky deposit forms on glass surfaces. Electrical lines are also affected.
And everything that absorbs and releases moisture loses its utility value over time. This applies to the filters on the darkroom lamp as well as to chemical powder substances that are no longer shrink-wrapped in their original packaging.

Above all, however, photographic papers suffer, since their gelatin layer was specifically manufactured to readily absorb moisture – otherwise you could not process them without problems. Unfortunately, the paper also absorbs moisture from the air, releases it again and thus “ages” very quickly. The reproduction quality is negatively affected, and it can even happen that the paper stains.  Even if you can ventilate thoroughly, it is a good idea not to store large stocks of papers and chemicals in the laboratory itself.

A shelf that is normally tempered and dry somewhere in a dark corner of the home is much better for this.  In your lab, you will need at least two separate work areas: one for your enlarger, where you will do all the “dry” work from film spooling to cutting paper sizes; and a second for all the wet work of preparing chemicals, developing film and paper, experimenting, and finally, of course, drying the finished images.