How do I tell whether a fault is the camera or the lab?

Look at the edges of the film where the frame numbers and manufacturer markings are printed. If those edge markings are present and sharp but your images are blank or ruined, the problem happened in the camera. If even the edge printing is missing or damaged, it was a film-handling or processing error.

How can I be sure the film is actually advancing?

As you wind on the first few frames, watch the rewind knob or crank: it should rotate as the film pulls off the cassette. If it stays still, the leader has slipped out of the take-up spool and nothing is being exposed. Reload the film and confirm the knob turns before you carry on shooting.

Common Film Photography Mistakes and How to Fix Them

Every film shooter ruins a roll or two learning the ropes. Here are the classic mistakes, what causes them, and exactly how to stop them happening again.

Shooting film means occasionally getting a roll back that is blank, streaked or strangely doubled, and every one of those failures has a clear cause. The good news is that film mistakes are almost always mechanical and repeatable, which means once you understand what happened you can stop it happening again. Here are the classics, grouped by how they look when your scans come back.

Blank roll: nothing recorded at all

A completely clear roll with no images is the most disheartening result, and it usually means the film never advanced. On a manual-load camera the film leader can slip out of the take-up spool, so the rewind knob does not turn as you wind on. Always check that the rewind knob rotates when you advance the first couple of frames; if it does not, the film is not moving and you should reload. A blank roll can also mean the shutter never fired, or, in the darkroom, that the film was accidentally fixed before development. If the roll is clear but the frame edges show printing and numbers, the fault is in the camera; if even the edge markings are missing, it was a processing error.

Light leaks: streaks and coloured fog

Light leaks show up as red, orange or white streaks and blooms, often in the same place on every frame. The usual culprit is perished light seals — the foam around the film door on older cameras crumbles with age and lets light in. Replacing the door seals with new foam is a cheap, straightforward fix. Leaks can also come from loading or unloading in bright sun, so change film in shade or turn your back to the light, and remember that the first and last frames of any roll are the most exposed to stray light.

Double exposures: two pictures on one frame

Unplanned double exposures happen when the film is exposed twice without advancing. On cameras that require a separate wind action this usually means the film was not wound on, or a roll was accidentally run through the camera twice. If you like the effect you can do it deliberately, but to avoid it, get into the habit of winding on immediately after each shot. Some cameras also double up frames if the rewind button is knocked mid-roll, letting the film slip.

Fogging: overall haze and lost contrast

Fogging is a milky veil across the film that flattens contrast and can add colour. Common causes are expired or heat-damaged film, film left in a hot car, exposure to airport X-rays at high dose, or opening the camera back before the film was fully rewound. Store film cool, keep it out of the sun, and always confirm the roll is fully rewound before opening the back.

Loading errors and how to load correctly

Many failures trace back to the moment of loading, so build a reliable routine:

Seat the leader firmly into the take-up spool slot and make sure a tooth of the sprocket engages the perforations.
Close the back and advance one frame, watching the rewind knob turn to confirm the film is caught.
Take up the slack by gently turning the rewind knob until you feel light tension before advancing to frame one.
When finished, rewind fully and only then open the back. If you feel the tension suddenly release during rewind, the leader has pulled free and it is safe to open.

Thin, underexposed negatives and wrong ISO

Negatives that look pale and empty, with muddy, grainy shadows once scanned, are usually underexposed. The most common cause is the ISO being set wrong on a manual camera — the meter is told the film is faster than it is, so it gives too little exposure. Always set the ISO to match the film you loaded, and if in doubt with negative film, err toward slightly more exposure, since colour and black-and-white negatives tolerate overexposure far better than underexposure. A dead or drifting light meter causes the same result, so check your meter against a known-good reference now and then.

Scratches and drying marks

Fine parallel scratches running the length of the film usually come from grit in the felt light-trap of the cassette or on a squeegee, or from dragging the film across a dirty surface. Handle film by the edges, keep cassettes clean, and never wipe a wet negative with anything abrasive. Drying marks — pale spots and streaks that appear only after the film dries — come from hard water drying unevenly on the emulsion. A few drops of wetting agent in the final rinse and hanging the film in still, dust-free air to dry solves both the spotting and much of the dust problem in one step.

Building good habits

Almost every mistake in this list is prevented by a small number of consistent habits: confirm the film is advancing, set the correct ISO, load and unload in shade, wind on after every shot, and rewind fully before opening the back. Keep the camera's light seals fresh and handle film by its edges. None of these takes real effort once they are routine, and together they turn film from a lottery into a dependable craft where the rare failure is a puzzle you can actually solve.

If you get a puzzling roll back and cannot work out what went wrong, bring the negatives and the camera to Boston Camera and we will help you diagnose the cause so your next roll comes back clean.