Middle Grey 18%

[Barney]

Is 18% middle grey the middle of the film latitude? (B&W)

 

[Ian Grant]

Yes it's Zone V, it's used for calibration of all types, films, digital, colour & B&W.

Amazon 12"x12" £9.99 or another 30cm x30cm £19.93, seems metric ones are more expensive, despite being the same size

Ian

 

[thedistrictline]

As i understand it’s the middle for reflected print media

Camera meters etc are calibrated off a luminance middle value of 12.9% ish

Theres so much literature on it but it sometimes feels like the old apsc aperture battles back in the day

 

[hunnymonster]

Amazon 12"x12" £9.99 or another 30cm x30cm £19.93, seems metric ones are more expensive, despite being the same size

Ian

Possibly smaller - 12 inches is 30.48cm - I wonder how close to 12" the merchandise actually is?

 

[sk66]

Is 18% middle grey the middle of the film latitude? (B&W)

Not really... the film's latitude is whatever it is, and the middle of that is wherever you place it.

18% can be used to set the middle of the film's latitude as 18% in a print during development. Metering an 18% card when set at an appropriate angle will result in the correct exposure for a "light subject" (meters are calibrated to ~ 12%). And if the subject isn't a "light subject" the metered reading needs adjusted appropriately.

Kodak Grey Card R27 Brochure

 

[StephenM]

I'm going to show my ignorance, but 18% grey is a reflected reading, surely, and film density is measured by transmission. Isn't this comparing apples and beachballs?

You can expose to render a grey card completely white, completely blown highlights, or Black, just film base and fog. There's no connection to the film latitude.

 

[sk66]

I'm going to show my ignorance, but 18% grey is a reflected reading, surely, and film density is measured by transmission. Isn't this comparing apples and beachballs?

From the brochure:

• Density. You can also use the image
of the gray card as a neutral reference
of mid-tone gray to evaluate density,
either visually or with a densitometer,
in black-and-white and color negatives,
transparencies, and prints. Many Kodak
publications provide aim-point densities
for normal exposure for the KODAK Gray
Card photographed on Kodak color
negative films.