Continuity with Haze

[adamsteadi]

I haven’t seen this covered literally anywhere. When working with haze I feel as though the continuity of haze between shots/scenes should be a consideration. I’ve worked on a few features as a gaffer and a lot of commercials/films/spots as a Steadicam Op where we haven’t used it at all. Is there a way to utilize haze and try to keep a continuity of it within the same scene/take? What do you look for? What does Ridley Scott do? I don’t know how this could have been accomplished in the film days when there was no play back (maybe they weren’t as concerned with continuity then?, and maybe I shouldn’t be now? LOL).

Topic

[gabj3]

The ideology is a spot meter and an 18% grey card or a white card—anything with constant reflectance, not specular.

Set the card up; if you want to be diligent, take a reading…

Haze the room and stand XYZ meters away from the grey card (the XYZ number should be replicable and marked).

Take a reading; that value partly defines the haze density between you and the grey card. If all other variables stay the same (distance, light level, etc), a change in that reading would indicate a change in haze density.

Infinityvision.tv

[Stip]

I’m not sure what Ridley Scott uses but if you mean older films, chances are they used the oil based DF-50 hazer. It’s great but leaves nasty residue.

The finer the haze, the longer it hangs in the air, the easier continuation. The likes of Pea Soup Phantom Hazer and MDG Atmosphere produce ultra fine haze that leaves almost no residue.

But maybe you want to ‘see’ more of the haze. Common names like Antari, Martin/Jem, Look are more affordable and produce much bigger particles, but also continuity gets tricky – imo you’ll need a guy just to take care of the haze.

There’s also a different kind of solution to fix continuity: a fantastic software plugin called ‘Scatter’ by Video Village, reproducing physical accurate diffusion of various filters – among them the haze-emulation filter ‘Smoque’ by Tiffen. Scatter could be used to compensate continuity differences in shots within a scene.

[adamsteadi]

To further clarify spot metering for this…..

I would presume that no matter what angle the shot is coming from within the same lit scene, you would always go back to the exact same placement of gray card and the exact same marked spot for taking a reading; but where is the best placement for the grey card? I don’t think I would put the gray card in a direct shaft of light (highlight areas) or somewhere where we are too dark in the shadows either. Maybe it is better for a reading to be taken somewhere in the middle? Also when we go in for the close ups and overs and tweak the lighting, the grey card is going to likely be more or less exposed so theoretically the grey card will be giving a different reading.

I realize this is not an exact science as nothing is in lighting. Are we just trying to get it close enough?

As it is needed, I do see this taking up a bit of time on set.

Excellent break down of the different types of haze. Thank you for that. We want to try and get as much in camera as possible first, then using the haze-emulation afterwards to help with continuity sounds terrific.

[Roger Deakins]

I have worked with effects teams that use a densitometer. That is really accurate but I would still adjust the level by eye. The issue being smoke in a backlight looks heavier than in a side light!

[gabj3]

Lighting is an exact science if you want it to be.

Maxwell’s equations surrounding electromagnetism can be pretty thrilling!

However, you hit the nail on the head because we measure everything in photographic stops, which is double or half the energy. Errors are generally negligible; a third of a stop difference is generally more than acceptable. In the world of energy, that’s 30% of total power.

Because of various laws of electromagnetism, angle plays a factor. It’s typically referred to in cinematography as ‘Lamberts Cosine Law’ < – however, this can also be derived from Maxwell’s equations.

The more obtuse of an angle to the normal of the grey card, the more ‘light loss’ you have.

So, keep the angle normal. I recommend lighting your grey card with the same intensity as your key/shooting stop.

You can set it up anywhere in the room with the same haze density as the set. I.E., a corner of a set.

I’d recommend sacrificing a little light at a fixed distance from the grey card. When shooting, turn it off.

Keep everything identical; the only variation should be the haze density.

A plug-in to introduce haze is akin to a plug-in to introduce a filter or any other optical variation. It is inherently possible to do so, but it will never be truly accurate.

 

Infinityvision.tv

[Stip]

A plug-in to introduce haze is akin to a plug-in to introduce a filter or any other optical variation. It is inherently possible to do so, but it will never be truly accurate.

I encourage you to look into Scatter (Video Village). It is accurate in emulating filter diffusion to a point where it’s visually indistinguishable to the corresponding filter.

The haze emulation filter (Smoque / Tiffen) within Scatter is not meant to replace haze – of course it cannot – but to even out differences between shots should they occur, and it does a nice job of achieving this.

[adamsteadi]

Wow, holy smokes! Densitometer? Never even knew they existed. So many presumptions from me but I would think if the back light is heavier than the side light it is because we are seeing more directly into the depth of the haze in the scene than a sidelight would portray. Makes total sense.

[Author]

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