What does a Black Pro-Mist filter do? The glow, explained

What does a Black Pro-Mist filter do? It's a diffusion filter that makes the brightest parts of a picture glow softly into their surroundings, and it lowers the overall contrast a touch. Tiffen, which makes it, says it does that while keeping detail, which is what separates it from an old-fashioned soft-focus filter.

The look is suddenly everywhere. This autumn alone, Fujifilm announced an Instax film with the glow built into the emulsion, added a Soft Glow filter to its X half camera, and the iPhone 18 Pro gained a Glow texture. Here's what the effect actually is, and how to get a convincing version on a phone.

What a Black Pro-Mist filter does

Tiffen's own product pages describe four things the filter does:

• Tames the highlights. It reduces the value of the highlights while slightly lowering the overall contrast.
• Softens skin. Tiffen says it's especially good at smoothing wrinkles and blemishes, which is why it's popular for portraits and beauty work.
• Keeps detail. Unlike a traditional diffusion or soft-focus filter, the Pro-Mist range causes little loss of detail across the image.
• Spares the shadows. Compared with Tiffen's regular Pro-Mist, the Black version lowers contrast with less lightening of the shadows, for a more delicate effect.

That last point is the whole reason the "black" version exists. Regular mist filters can wash blacks out to grey. Black Pro-Mist keeps the dark parts dark and puts the glow where the light is.

Which strength to choose

Black Pro-Mist comes in densities written as fractions. Higher numbers mean a stronger effect.

Grade	What Tiffen says it does
1/8	The mildest grade
1/4	More contrast and highlight reduction than 1/8, less than 1/2
1/2	Stronger again
1 and up	More contrast and highlight reduction again

Tiffen describes 1/4 as still allowing a "soft, pastel-like quality of light", and its range goes well beyond 1/2: its UK site lists the Warm Black Pro-Mist up to grade 3. For everyday photos, start low. Strong mist looks great in a music video and odd on a birthday cake.

Bloom, halation and diffusion: the naming mess

Tiffen's UK listing describes the filter's spill as a kind of halation. That's a looser use of the word than film photographers mean. In film photography, halation means something specific: a red-orange halo caused by light bouncing back through the film itself, as we explain in what halation is.

What a diffusion filter makes is closer to what photographers call bloom: a softer glow where bright areas spill into their surroundings, caused by light scattering in the filter. The quick tell:

• Diffusion glow mostly takes the colour of the light. A white lamp glows white, a warm lamp glows warm, though Tiffen notes a warmer spill at heavier grades.
• Halation leans red-orange and hugs the edge of the brightest highlights.

Real night scenes on film can have both. A digital look that confuses them is usually the giveaway.

The diffusion look is suddenly everywhere

The glow has moved from filters into film, cameras and apps:

• Instax SQUARE Soft Haze. Announced by Fujifilm on 27 October alongside the instax SQUARE 2 camera, this square-format film gets soft light effects and warm colour tones from a newly developed emulsion. The camera reaches Japan on 13 November. (If you're choosing a format, here's how Instax and Polaroid compare.)
• Fujifilm X half Soft Glow. Firmware 2.00, released on 30 September, adds a Soft Glow filter that softens tone in the highlights to enhance the glow.
• iPhone 18 Pro Glow texture. Photographic Styles on iPhone 18 Pro models offer Soft Skin, Glow and Film textures, plus a Grain control.
• Snapseed Bloom. Google's free editor includes a Bloom tool for a soft diffusion around light sources, alongside a Halation tool, and it now has a free film camera too.
• MARS. This iPhone black and white app is built around a Glow control, which its maker describes as how much the light overflows. It's part of the black and white film look it's chasing.

Filter or software on a phone?

You have two routes on a phone.

A real filter. Clip-on and magnetic mist filters are made for phones. Tilta, for example, sells a magnetic Black Mist filter for iPhone in 1/4 and 1/2 strengths. The glow is optical, so you see it live and it reacts to real light. The catch: phone HDR pulls bright highlights down to save detail, which can tone down the very glow you paid for. We explain that in why phone photos look overprocessed.

Software. A glow effect in an app or the camera itself is free and adjustable. It's only as good as its model of light, though. Use this checklist to judge one:

1. The glow scales with brightness. A bare bulb should glow far more than a lit window, and mid-tones shouldn't glow at all.
2. The shadows stay dark. If the whole frame goes milky, it's a contrast slider, not a mist.
3. Detail survives underneath. The glow should sit around edges, not blur them.
4. The colour follows the light. A uniform orange halo on everything is halation done badly, not diffusion.
5. It's gentle in daylight. Like the filter, the effect is easiest to see at night or against bright backlight.

Where trycheese fits

trycheese's film looks are tuned like film stocks, with colour, grain, red halation and a soft highlight roll-off baked in at the shutter. If you like the pastel end of the mist look, Brie, our soft, low-contrast look, is the closest in mood. There's no live filter preview, so you see the result a beat after you shoot.

trycheese isn't out yet. It's coming to iPhone and Android together, free at launch. In the meantime, try any glow effect on a streetlamp at night. Two seconds of looking will tell you whether it's mist or a sticker.