The darkroom generally consists of two sides or areas, the wet and the dry. The configurations of darkrooms vary greatly, but there are general similarities. Darkrooms are usually divided (if only in theory in really small ones) into two sides: dry and wet. The dry side is where the enlarger is, and the wet side is where the chemistry is. The following describes what kind of tools are found on each side. Before that, however, there are some overall considerations.
A darkroom should be positively ventilated. Air conditioning can serve to do this, but an exhaust fan is much better. The ideal solution is a hood over the sink where chemicals are being used. This will draw the fumes up and away. The ideal is to get a complete change of air about every three minutes. A fan (exhaust) and louver (intake) is a good route to take. Fixer and acidic stop bath are the main culprits here. Using a citrus-based stop bath, rather than an acetic one is also recommended.
A bright darkroom is a happy one. Either OC (amber) or red safelights should be used. The preference is really for red, as many materials require red, and it is also safe for materials that can be used under OC. Walls and ceilings need not be black, or even dark. If the only light is safe, then reflecting that light from walls, ceilings and counters does not matter. Light walls make for a brighter darkroom, and a more pleasant work area.
Power is mentioned here in one respect: outlets near water need to be of the GFCI type. This protects against electrical shock, and is code pretty much everywhere.
The Dry Side
As mentioned above, the main component of the dry side is the enlarger. Enlarger are sort of reverse cameras: instead of taking in light to capture an image, they project light to form an image. While not overly complicated, there is enough to be said that they deserve their own section.
Printing Frame, or Easel
A printing easel is used to hold the paper. These are usually fairly sturdy metal units, with either two or four movable blades. The blades lift up, and the paper is inserted into either the top left corner, or into a slot in the base, and the blades are then lowered, holding the paper flat. Also around are speed easels, which do not have blades. Instead, the paper is inserted in a kind of slot, with no borders. Easels are intended to simply hold the paper flat, but in the case of the four-bladed type, where all four blades can be adjusted, amy laso be used for cropping.
Two-bladed easel are particularly prone to ruination through mishandling. Lifting the blades by the blades and not the frame will lead to the blades being bent out of flatness and square, making the whole thing pretty useless.
A contact frame is also os use, more for, well, contact printing versus enlargements. The are wood or metal frames with a removable back, and a piece of glass hels in the front. Materials are place inside, and when closed up, the frame tightly presses the materials together, ensuring good contact. A piece of plain glass works well enough for printing contacts sheets and photograms.
A timer is used to control the enlarger. Most now are digital, but there are analog ones out there. They are plugged into the wall, and then the enlarger plugged into the timer. Enlarger timers will have two settings. Focus turns the enlarger on and leaves it on for focusing. Time (or run, or expose) turns the enlarger on for the time set. Most are repeatable. That is, you set the time once and it will reset to the same value. Most digital ones will be able to be set for full seconds, and/or tenth of seconds. Some may also control the safelight, although this is not really necessary.
A timer is also used for processing the paper. This one is usually analog, with probably the most typical being a model like the GraLab 300. A regular wall clock would work, just so you can see the second hand.
Polycontrast filters are used with polycontrast papers to manipulate contrast. These are either inserted into the lamp house, or, more commonly, used under the lens. They are numbered from 0 or 00 to 5, usually in half steps, and range in color from yellow (0 or 00) to magenta (5), and go from flat to contrasty respectively. Much more on the use of these will be found the sections on enlarging and contrast control. It should be noted that some care should be used when handling these filters. Wet hands can dissolve the gelatin coating containing the color, making them useless.
Also called grain focusers or grain enlagers, these look sort of like a microscope. They are placed on the easel, and magnify the image to where you can actually see the film grain come into focus.
Some other things are handy in the darkroom dry side. A paper cutter (or at least scissors) should be available to cut down paper for tests. Some prefer to use a paper safe rather than having to open and close boxes.
The Wet Side
The wet side setup varies as much as anything. What the configuration may be completely depends on a given situation. Below are somewhat general descriptions of tools and fixtures.
A darkroom does not require running water. Prints can be held in a try, and then taken out of the darkroom to a water source for washing. That being said, a darkroom with running water available is far more convenient and efficient than one without.
A darkroom sink is long, wide, and shallow. They come in plastic, fiberglass or stainless steel. They are not inexpensive. Like running water, a darkroom sink provides ideal working conditions. The goal is to be able to lay out all the chemistry you need in trays at one time. The sink holds these, keeps chemistry from getting everywhere, and allows for easy clean-up.
Processing trays are relatively shallow, and usually plastic. They are also fairly inexpensive. I prefer Paterson, as the trays are pretty rigid, but the type of plastic used is flexible enough to not crack easily (or at all). These trays seem to last forever, even with the kind of abuse they get in a student-occupied lab.
Trays should be at least a bit larger than the paper you are processing. So, an 8 x 10" tray is a little larger than 8 x 10". Some prefer to use the next size up. Using 8 x 10 trays for 8 x 10 paper works just fine. The trays are big enough, and deep enough to hold enough chemistry for an extended session.
Some kind of measuring device is required. One-liter plastic graduates are ideal in the darkroom. They are large enough (an 8 x 10" tray should have about a liter/quart of solution) and accurate enough. Smaller graduates are better for actually mixing chemistry, and are necessary for film processing.
Depending on the amount of use, chemistry can be stored in anything from liter brown bottles to five-gallon dispenser tanks. The school darkrooms I use make use of the latter. A two-gallon version, with a floating inside lid holds the developer, and five-gallon version for stop and fix.
Whatever the method used, make sure all storage bottles and containers are clearly marked with their contents.