Feiertag Loc: British Columbia, Canada

I know that Kodak came up with this idea/method but why not 0%? You shoot white subjects, you have to keep the gray factor in mind. Why not design a camera that gives you the option, that meters at 0%, not 18% gray?

burkphoto Loc: High Point, NC

https://www.google.com/search?source=hp&ei=Fd-NWunlNeq0ggexyq7YDA&q=history+of+18%25+gray+card&oq=history+of+18%25+gray+card&gs_l=psy-ab.3..33i22i29i30k1l10.608.7962.0.9530.25.24.0.0.0.0.140.2003.20j4.24.0....0...1.1.64.psy-ab..1.24.2001.0..0j35i39k1j0i131k1j0i20i264k1j0i131i20i264k1.0.FLvvCamT5wE

Knock yourself out reading all the answers. Lots of debate out there. 12%? 18%? Meh... I'll leave the whys to the scientists.

What the hell. All I know is, if you set a camera on Natural or Neutral Picture Style, and make an auto exposure of nothing but a gray card, then translate that readout of ISO, f/stop, and shutter speed into actual FULL manual camera settings, THEN do a white balance off the same gray card, you will get VERY accurate color rendition of your subject. It might not be perfect, and it might not be what you want in a raw file, but it is a great starting point for straight-out-of-camera JPEGs recorded under controlled lighting conditions.

14kphotog Loc: Marietta, Ohio

Sounds like a straight on answer( burkphoto.)

r.grossner Loc: Rockford IL & Sarasota FL

I have used the palm of my hand in a pinch.

Feiertag Loc: British Columbia, Canada

Thank you for the post. It appears that it was setup for B&W shots. When I shoot white objects in the colour format I want whites to be white, not gray. Maybe there needs to be a change? It fails in the colour format, for me. I always have to compensate for the 18% factor. I still don't get it!

HarryBinNC Loc: Blue Ridge Mtns, No.Carolina, USA

The 18% grey card was a valuable tool back in the film era, and can still be useful with digital. Auto exposure systems in cameras (and light meters) are easily fooled when you are shooting something that doesn't have a mixture of brightness values that conform to the "average" scene that the meters are calibrated for. The classic examples are shooting a polar bear on the snowfield on a sunny day or the black cat in a coal bin (or vice-versa). Those are the extremes, but there are also a lot of more complex scenes that will trick the metering system and/or the photographer. When you recognize one of those tricky situations or you don't have time to experiment , you can meter on the gray card, which guarantees your exposure will be at least in the ballpark. Of course, with digital, you can chimp and adjust until you get it right - if the subject waits around for that. Your 0% (or 100%) meter wouldn't give you what you need - the actual luminance value of the light falling on the subject. That is the beauty of the gray card - it takes the subject's variablility out of the equation and tells you how much light there really is.

burkphoto Loc: High Point, NC

It is all about displaying textured whites (threads in a white shirt, for example) in photo prints. Photo paper (conventional Kodak silver-halide wet process technology) only reflects about 90% of the light falling on it. The top and bottom 5% of tones are not really visible to most people. So... the idea is to force everything into a value range of about 12 to 242 (and for some other papers, around 18 to 236)! That means 1/3 stop underexposure of a JPEG to preserve highlights, and Neutral or Natural Picture Style to pull in the shadows.

If you photograph a gray card, the correct reading for middle gray is around 124, 124, 124 RGB in an sRGB JPEG, give or take a few points. Adjusting exposure with a typical dSLR set as I described earlier will give you clean, textured whites, visible on photo paper. It will give you detail in the shadows that would plug up if you printed the full range. And there is still a little bit of overhead in the highlights that you can "dial out" in post production.

Now, if you're only viewing images on a computer monitor, that is an entirely different story! You may want an additional 1/3 stop of exposure, and the Standard Picture Style instead of Neutral/Natural. Good monitors, properly calibrated and profiled, can display tones from 0-255. Exposure compensation dials are your friends... HOWEVER, ETTR leaves little or no latitude for highlight recovery from a JPEG.

If you are recording raw images, no problem... Do what you would do for a SOOC JPEG, then open up a stop, or even a little more (EBTR). Back in the office or home, adjust blacks, whites, shadows, highlights, and exposure in post-production. Ignore the overexposed mess in the preview JPEG...

blackest Loc: Ireland

The world is mostly mid gray on average , but sometimes its not.

For whiter whites you can do 2 things.

Incident light reading should place tones correctly
Or meter off something mid gray or the back of your hand at a pinch.

You probably have an exposure lock button use it hold the reading you got from the gray card or back of your hand and shoot your white subject it should be white.

Your white is gray only because the camera assumes we are in a gray world.

Bill_de Loc: US

With all the photography you do, very nicely, you never thought to research this?

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HOT Texas Loc: From the Heart of Texas

White reflects light, That can cause getting the balance wrong, also if you shoot at a flat surface it can reflect different lighting at different angles, adding 18% gray helps this problem.

https://www.youtube.com/watch?v=cOYtgWqn-7U

rgrenaderphoto Loc: Hollywood, CA

Grey is a neutral color, white is not.

Watch JP Morgan's video:

https://www.youtube.com/watch?v=Ho_C2ZvOzJk&t=220s

Feiertag Loc: British Columbia, Canada

Thank you for your comment, Bill. I knew the 18% factor and compensat for it. I am just curious as to why this has to be the case?

Bill_de Loc: US

I figured that with the quality of your pictures you probably know more than many of us here.

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blackest Loc: Ireland

This page is useful
https://en.wikipedia.org/wiki/Middle_gray

It also has a handy patch to adjust your monitor , my screen was way too bright.

Feiertag Loc: British Columbia, Canada

Thank you for the compliment, Bill. I learn something, every time I push the shutter. When I screw up, I check as to why? I then try not to repeat the blaring error. Cheers!

Harold