What is 18% gray in cinematography?

its about Gray card.
What is 18% gray in cinematography?
18% gray card is used when using a reflective light meter to get a good light reading. When shooting film, we usually use a studio incident light meter, so no gray card is necessary.





If you buy a Kodak 18%/white card, they include a full explanation now to use the card.





The 18% gray card is also use when shooting still photography, so most photographer will know how to use the gray card as well
What is 18% gray in cinematography?
meters in mainly every camera out there use whats called reflective metering to find an exposure. reflective metering measures the light reflecting off the subject, so in order to get an average reading of the scene, the meter ALWAYS shoots for 18% grey, which is precisely between black and white. its works great when there are both whites and blacks in the scene, but in a scene of all white or all black, problems occur.





so the grey card allows your camera to read the scene as an incident meter would, in that it measure light falling on a subject, over light reflected.





so if you shot an image in the snow, the meter would underexpose in trying to make the white become grey, and if you were shooting a black cat, it would overexpose it to become grey.





you take an exposure reading of the grey card by itself in the same light as your subject, and you get an accurate exposure.





i still use them in rare circumstances, but im sure were in the minority in that department.