WhiBal Reference Card: Which Zones ?

[Ken Lee]

The WhiBal Reference Card is designed for getting correct color balance when shooting in color.

Does anyone know which Zones correspond to the 3 basic gray values on the card ? Apparently, the demand for WhiBal doesn't support a custom order of materials which are exactly 18% reflective.

Does anyone know of an 18% gray card that is weather-resistant and fade-proof ? That's really all I'm looking for.

[Helen Bach]

I couldn't find the reflectance info on their site. The section in the user manual that might have contained the data appears to be only the headings, with the text not yet added. Could you ask them?

Best,
Helen

[Michael Graves]

The Delta One is just what you're looking for. It is a neutral gray plastic card that is about 8" x 10" in size and ships in a ziplock bag.

[Ken Lee]

WhiBal has a forum, and on it, people have asked the inventor/proprietor to come out with a version in 18% grey. He reiterated what he states in his videos, over and over, that the device is meant for white balance only - not exposure calculation. He also suggests that to order a batch of optically neutral plastic in that shade, would be cost-prohibitive at this time, given his volume of business.

His approach is geared to the world of digital imaging, and I can respect the wisdom of that business decision. Perhaps he was unaware of the 18% reflectance issue when he embarked on his enterprise. It is, after all, a relic of 20th century technique.

Further Googling has led me to discussions that challenge the validity of the 18% number itself, with regards to light meters and Zone V. Apparently, 18% reflectivity is a printing standard, not used by light meter manufacturers. According to Meters Don't See 18% Gray, the real number is closer to 12%, but the wrong number has been in circulation for many decades.

Our esteemed Ansel may have gotten it "wrong" in this vein, but was somehow able to overcome the blunder.

[Ken Lee]

The Delta One is just what you're looking for. It is a neutral gray plastic card that is about 8" x 10" in size and ships in a ziplock bag.

Thanks Michael - I have looked online for it, but nobody mentions plastic.

[Kirk Gittings]

Thanks Michael - I have looked online for it, but nobody mentions plastic.

I have one but I bought it many years ago. I actually cut it into 1/4s put a square of velcro on it and stick it to whatever so it doesn't get lost. A 4x5 plastic grey card is much more handy and WASHABLE! They are also slightly darker than the Kodak cardboard ones. How much? I don't have one to compare.

[Kirk Gittings]

Further Googling has led me to discussions that challenge the validity of the 18% number itself, with regards to light meters and Zone V. Apparently, 18% reflectivity is a printing standard, not used by light meter manufacturers. According to Meters Don't See 18% Gray, the real number is closer to 12%, but the wrong number has been in circulation for many decades.

Interesting, in almost 40 years this is the first time I have heard this, but it may explain a "fudge" factor I have leaned anecdotally to apply with transparencies exposed from a grey card.

[Ken Lee]

So far, I have found 2 items which might be an improvement over the venerable Kodak cardboard design:

The Fotowand Standard Grey Card, "made of a semi flexible plastic which is very durable and waterproof"

The Alpine Innovations Spudz, "the most Convenient 18% Gray Micro-Fiber Cleaning Cloth, Extra Large, 10" x 10"

[Helen Bach]

In many cases all you need is a consistent target, not necessarily an 18% target. The way that AA uses the grey card in the Zone System to determine a film speed means that there is no 'mistake' in his use of it. The mistake is to make a general statement that meters are calibrated to it, or that an incident reading is equivalent to an 18% grey card reading.

Other practical film speed determination methods use the 18% card: The aim density method of speed determination correlates an exposure of an 18% grey card to an aim density of the negative.

One of the original grey cards for metering was the 'Neutrowe'. That had a reflectance of 14%.

If the makers of the WhiBal card are unable to publish a consistent reflectance value for each patch, then why not just measure one with a densitometer?

Best,
Helen

[Henry Ambrose]

snipped.....
The mistake is to make a general statement that meters are calibrated to it, or that an incident reading is equivalent to an 18% grey card reading.

How true!

Assuming you select and use a gray card, you will soon find that the reflective meter reading off that (or any) gray card is not precisely repeatable. Changing the reading or lighting angles changes the amount of light the card reflects. Your readings will not repeat precisely.

If you are calibrating a wet darkroom (for instance) system all that you need to do the job is a reference that remains stationary. If your gray card is 12 or 15 or 18% reflectance, as long as you use the same reflectance through your testing it will come out fine. So pick a card and use the same one always. Your card becomes part of your system.

If you look at a dozen gray cards in a dozen photographer's bags you'll likely see 12 different shades of gray. High precision in the reflectance of a gray card is not a requirement.

Good try, but you're not going to get the absolute answer to exposure you may be after.