Print gray card

[truls]

Someone knows if it is possible to print out a gray card for light metering, and how?

[Stephen]

Not easily, the 18% grey card is actually a mid grey, 50% white, 50% black, geometrical half way between pure white and dead black.

The ANCI standard is actually to use a 14% type card, and incident meters are set to work with this standard, but 18% was adopted by Kodak, mainly by pressure from US photographer Ansel Adams, who widely set his exposure using Kodak made cards as reference.

However the 18% can be compensated for by the 1/2 stop anyway, and who works to this level of precision anyway?.

The main user is the commercial photographer who must ensure consistency, not accuracy as such, and any grey card would do, as long as it's the same one. by using the Kodak product it means that all other variables apart, the card is the consistent factor.

The best bet for a home produced card, would be to print a very, very, fine mosaic of squares of black on a white background, this must have near 50% mid reflection, but I suspect it will be too dark, and would need a careful series of test shots taken, with exposures verified by an incident meter.

Once the pattern is determined to work, then print several copies, and use them, but they might alter a bit with age, which the Kodak do not if kept clean.

However as said before they are a very scientific approach to exposure, and most meters and auto cameras do not need it to work fine, just alter the base ASA to compensate for general photography, to get the results you want. Most shutters etc., are not really accurate enough to use such fine precision, when added to film tolerances, plus processing variables of both the film and print...it all obscures the approach, which when it comes down to it is experience in getting it, right, or taking a series of graduated bracketed exposures for really important shots.!

Ansel Adams liked to get it right, as he worked in large format, taking a series would be expensive and the film bulky, but it is easy in 35mm.... or exceedingly easy in digital.

Stephen.

[mickeyobe]

truls,

This is probably not the accuracy you desire but these "grey cards" have served me well through the years and required no space in my camera bag and are available almost everywhere.

A blue sky 90 degrees from the sun.

Green grass.

A worn, not new, asphalt road.

Mickey

[truls]

Thanks, I will try the black square on white until the metering is right. Because of the snow I will need a grey card, not for precision, but more to get an idea of the light conditions. Maybe I will follow the ANCI standard 14% instead of 18% Kodak.

[Rachel]

truls. if you do a search on the web for DIY photographic grey (gray) cards you will find quite a lot of info on the subject and ways to do it with photoshop.

[truls]

I use Gimp, here is my (lousy) effort so forth:

1. Choose new image, click OK (640x480)
2. Fill the emty image with a gray grey color. Here is the setup:


I think I made some error here, the grey gray did not turn out properly. Which values to use in the Gimp screenshot? I am not very good at this. If this can make a howto for others that's also nice. A test of the exposure outside, a cloudy day:
Without grey card: 1/125 @f.5.6
With grey card: 1/250 @f.5.6

[Doug T.]

Hi Truls!

I've used the palm of my hand on several occasions, and that has worked for me.

Here's a website that you might find interesting:
diyphotography.net/

They have some great ideas for photography "on the cheap".
For example, they have wonderful directions for making matchbox pinhole cameras, or your own backdrop.
It's a good site

Doug

[jack]

truls,

This little tutorial on how to make a 18% grey card with Gimp seems easy enough. I would be a bit concerned about choosing the right type of paper or card stock to print on though as different paper surface can affect the reflectance characteristic and therefore the reading from a light meter.

Jack

[Stephen]

But the standards only apply if you make comparison to the ANCI standards, any gray will actually do, for your use as a standard for you.
The reason for the cards accuracy was that a shot taken using one was reproducible, an example was Ansel Adams , who used them , but he did not print hi own work, so relied on the accuracy he took the shots to, making them reproducible by others to his accurate exposure.

Accurate exposure is not improved by any equipment, meter, cards or system, it is only accurate when it is right for the purpose you intend. The meters only help stop wasted film, but the only really accurate way is to take a sequence of bracketed shots.

A card gives a good indication of the light falling on the scene to a meter, and assuming all things are working, then a camera will reproduce that grey in the final shot.

But there are simpler ways, just compensate for snow say, reset the meter, add exposure, it is just as consistent as using a card. Or more simply get a Weston meter with the invercone fitted, it works as well as a card or better.

Never fall for the trap of making exposure over complex, it isn't, but it is easy to get it completely wrong, but as long as you understand photography principles, use a meter and compensate for the conditions.

Stephen.

[truls]

jack: You are the man, thanks for the link, as I did not find it myself, it worked perfect!!

Tanks everybody else, I am not getting scientific, but I needed a way to meter a base exposure. No more to say, case closed.

[herron]

Here's a page from my main photo web site many have found helpful.

[truls]

Thanks Ron, but I live above the arctic circle, and from november to late januar we have no sun, beacuse of the polar area. A gray card will be most important.