One of the most common darkroom setup mistakes I see beginners make is skipping the safelight test. You spend hours setting up trays, chemicals, and your enlarger, but that one tiny light leak or an incorrectly placed safelight can fog your paper before you even start developing. And you won’t notice until you pull a print out of the developer and see a flat, muddy mess. That’s why a simple safelight test should be the first thing you do when you turn off the room lights.
What is a safelight test and why does it matter?
A safelight test is basically a quick experiment to see if your darkroom light is truly safe for your photo paper. Even though safelights are designed to emit a wavelength that doesn’t expose most black-and-white papers, they can still cause fogging over time, especially if the bulb is too bright, the filter is old, or the light is too close.
Without this test, you might waste paper, chemicals, and hours of work. A fogged print looks washed out, with no true blacks or clean whites. It’s one of those darkroom mistakes that feels like a puzzle until you realize it was the light all along.
How to perform the coin test for safelight fogging
The coin test is the standard way to check your safelight. It takes maybe ten minutes and costs nothing. Here’s how to do it:
- Grab a piece of your photo paper (an RC or fiber paper you plan to use) and place it on your work surface under the safelight, exactly where you would normally put your paper while handling it.
- Lay a coin, key, or any small opaque object on the paper. A quarter works well.
- Turn off the room lights. Keep only your safelight on, just like during printing.
- Wait 5 to 10 minutes. Do not move the coin. Stay still or leave the room.
- After the time is up, remove the coin and develop the paper normally (developer, stop, fixer, wash).
- Look at the developed sheet. If you see a faint white outline of the coin (meaning the area under it remained white while the rest fogged slightly gray), your safelight is causing fogging.
If the paper comes out completely white and even, your safelight is safe for that exposure time. If you see the coin ghost, you need to fix something before you ruin prints.
Common darkroom setup mistakes that ruin your safelight test
Even a careful test can trick you if you overlook a few basics. I’ve made these mistakes myself, so I’ll save you the hassle.
- Using the wrong bulb. Many red or amber bulbs sold as “party bulbs” are not true safelights. Use only bulbs designed for darkroom safelight fixtures, or proper LED safelights meant for photo paper.
- Placing the safelight too close. A general rule is at least 4 to 5 feet from your working area. The closer the light, the higher the risk of fogging, even with a good filter.
- Old or cracked safelight filters. Over time, filters fade or get tiny cracks that let through white light. Replace them if you suspect aging.
- Light leaks from your darkroom door. Strip lighting around the door frame or a gap under the door can let in white light. The coin test won’t catch that unless you place paper near the leak.
These darkroom setup mistakes are easy to fix once you know they exist. The coin test is your early warning system.
How to fix a failing safelight and prevent fogging
If your test shows a ghost coin, don’t panic. Start by moving the safelight farther away. Sometimes a few extra feet is all it takes. If the fogging persists, try a lower wattage bulb. A 15-watt incandescent bulb is typical for a small darkroom. For LED safelights, check the manufacturer’s recommended distance.
You can also swap the safelight filter or replace the whole unit. I personally use a red LED strip mounted under a shelf at around 5 feet, and I test it once a month. Another option: put a shield or a louvered cover on your safelight so the light doesn’t shine directly on your paper. Angle it toward the ceiling or a wall.
And here is a pro tip I learned the hard way: do the coin test again after any change, and also test with a longer time, like 15 minutes. Some papers are more sensitive than others. Ilford Multigrade, for instance, is fairly forgiving, but some graded papers fog fast.
Other darkroom printing mistakes that mimic safelight problems
Sometimes you see fogged prints and blame the safelight, but the real culprit is something else. One common issue is using expired paper. Old paper often has a base fog that looks similar to safelight fogging. Another is developer contamination. If your developer is oxidized or too warm, it can cause a chemical fog that shows up as an overall gray tone.
Also, check your enlarger for light leaks. A cracked negative carrier or a loose lens board can let stray light hit the paper during exposure. The coin test only tests your safelight, not the whole room. To catch other darkroom mistakes, run a blank exposure test: make an exposure with no negative in the carrier (lens capped) and develop it. If you get any density, you have a light leak somewhere besides the safelight.
Keep your chemicals fresh, your thermometer accurate, and your paper stored in a light-tight box. And test your safelight every few months because bulbs can drift in output, and filters can degrade without you noticing.
Film photography darkroom setup tips for beginners
If you are new to darkroom printing, start simple. You do not need a big, expensive setup. A bathroom or closet works fine as long as you can make it completely dark. Use the safelight test as your first step after taping up windows and sealing door edges with blackout cloth or foam tape.
Organize your trays in a logical order: developer, stop bath, fixer, and a water wash. Keep your safelight positioned so you can see the trays without casting shadows. I like to put mine above the developer tray because that is where you watch the image appear, but it can be anywhere that passes the coin test.
One more tip: put a small sheet of white cardboard under your paper in the developer tray. That makes it easier to see the image appear, especially in dim safelight. And always handle undeveloped paper with clean, dry hands. Oily fingerprints can cause spots that look like fogging.
Why the safelight test saves you money and frustration
Paper is not cheap. Neither are chemicals. One fogged 8×10 sheet might cost 50 cents or more, and if you run a whole printing session with a bad safelight, you can waste a whole box. Worse, you spend hours adjusting exposure times and contrast filters, only to find every print looks flat and disappointing.
A ten-minute coin test can prevent that. It is the smallest, easiest routine in the darkroom, and it gives you peace of mind. I do a quick test every time I change a bulb or move my darkroom setup. It takes almost no effort and has saved me from plenty of ruined prints over the years.
So before you pull that first test strip, grab a coin and a sheet of paper. Make the test a habit. Your prints will have cleaner whites, deeper blacks, and you will know for sure that your safelight is doing its job.
Next time you set up for a printing session, give the coin test a quick run. It takes five minutes and costs nothing but a sheet of paper. Trust me, your future prints will thank you. Happy printing.
#darkroomsetup #safelighttest #darkroommistakes #filmphotography #darkroomprinting
Leave a Comment