What Gray Card?

[xkaes]

And out of debates that are not photographic.

 

[pentaxuser]

Photographers should keep their palms out of the sun.

Funnily enough, I have seen probably 1000s of people sunbathing over the course of my life and I can't recall seeing any doing it palms upwards. I can't think of many outdoor jobs either that causes hands to be in a palm up position for more than a second of so

I have seen some pretty bad examples of severe sunburn and tanning but never a sunburned palm

My conclusion: Palms tend not change much over the 4 seasons

pentaxuser

 

[wiltw]

Not so. Just put a Styrofoam cup over the lens, and point it to where the camera will be. Instant incident meter. Wins hands down -- I mean palms down.

A solution, perhaps, but one which has the problem of occupying space in your camera bag, and requires care to prevent squashing it!

We just happened to have some unused styrofoam 8oz cups on hand, so I did a test and compared to Shady 5.6 corollary of Sunny 16, unbroken white coastal cover

1. Minolta Autometer Vf hemisphere: ISO 200, 1/200 f/5.6 +0.4 (cloudy sky)
2. Canon 7D 70mm FL, styrofoam cup: ISO 200, 1/400 f/5.6 (cloudy sky)
3. Shady 5.6: ISO 200, 1/200 f/5.6

Later, when sky had partly cleared (broken clouds, visible blue sky in opening)

1. Minolta Autometer Vf hemisphere: ISO 200, 1/250 f/11 (partly cloudy sky)
2. Canon 7D 70mm FL, styrofoam cup: ISO 200, 1/400 f/11 (partly cloudy sky)
3. Partly cloudy 11: ISO 200, 1/200 f/11

I think I'll keep a styrofoam cup in mind if I happen to be close to a cafe or a fast food place with coffee, only I forgot my incident meter, and apply a +1EV understanding about the cup reading, just like my palm!

 

[Sirius Glass]

Funnily enough, I have seen probably 1000s of people sunbathing over the course of my life and I can't recall seeing any doing it palms upwards. I can't think of many outdoor jobs either that causes hands to be in a palm up position for more than a second of so

I have seen some pretty bad examples of severe sunburn and tanning but never a sunburned palm

My conclusion: Palms tend not change much over the 4 seasons

pentaxuser

Neither have I, but in this thread reality went out the door many posts ago.

 

[pentaxuser]

Styrofoam isn't biodegradable; palms are.

Drew, is that palms as in palm trees? If so then that's certainly true but I can't work out what the relevance of biodegradability has to our subject.

pentaxuser

 

[DREW WILEY]

Just a joke. One is not supposed to use and throw out non-biodegradable products. Alternatives to styrofoam are being sought. In this area, styrofoam cups have been banned at coffee shops.

And Sirius - nobody sunbathes here in coastal rim of the Bay Area. As Mark Twain quipped, The coldest winter I ever experienced was a summer in San Francisco. But I have absolutely no doubt one could find a great many exceptions to your "palms never tan" here too. Beautiful "strawberry blonde" girls I went to high school with are now wrinkled deep deep tan, hands n' all, including palms, because they spent every summer at high altitude on horseback. Your statistical sample of alleged proof is really quite small given the bigger picture. Any geneticist or dermatologist would probably look at you crosseyed.

 

[xkaes]

Just a joke. One is not supposed to use and throw out non-biodegradable products. Alternatives to styrofoam are being sought. In this area, styrofoam cups have been banned at coffee shops.

That's what I always thought too -- and the recycling plant here will not take Styrofoam. But I just got a new Dell printer a few days ago, and it was surrounded by Styrofoam in the box, of course. Each piece of Styrofoam was clearly imprinted with big #5 recycling triangles. And this is not some new Styrofoam -- I got the printer for $10 because it's 10 years old.

 

[xkaes]

I think I'll keep a styrofoam cup in mind if I happen to be close to a cafe or a fast food place with coffee, only I forgot my incident meter, and apply a +1EV understanding about the cup reading, just like my palm!

I'm glad to see some verifying, corroborating evidence. Thank you.

People should also know that if Styrofoam cups are hard to find in their area, there are other, more durable, alternatives. One half of a WHITE L'EGGs panyhose egg will work just as well, and you can also purchase EXPO-DISCs and similar accessories that attach/screw into the front of your lens. The only drawback is that these alternatives usually cost as much, or more, than a simple, used incident meter on EBAY -- and many (most?) of these meters can be switched into reflectance mode.

 

[pentaxuser]

Just a joke. One is not supposed to use and throw out non-biodegradable products. Alternatives to styrofoam are being sought. In this area, styrofoam cups have been banned at coffee shops.

Any geneticist or dermatologist would probably look at you crosseyed.

Drew, I always try to avoid cross-eyed dermatologists who look at you as if you are nuts if you ask the wrong question of them

pentaxuser

 

[Nicholas Lindan]

...well, according to multiple test readings I have done on different days, the f/16 Rule of Thumb is a really fat thumb...
Finding a post I made years ago,

"at N38 degrees latitude, 1pm, in my back yard, with the incident light meter hemisphere held horizontal (aimed 'at the lens')...​

ISO 100, 1/100 f/16.0, and moving full circle the meter deviated to +0.1EV and -1.9EV"​

Kodak says for their "Sunny 16" rule that the sun is behind you and the picture is taken between 10am and 4pm.

Now that says 'boring' to me much more than any bisectioinal horizon in a competing interminable thread.

 

[wiltw]

Kodak says for their "Sunny 16" rule that the sun is behind you and the picture is taken between 10am and 4pm.

Now that says 'boring' to me much more than any bisectioinal horizon in a competing interminable thread.

As bad, or worse, than 'boring' is that your subject is squinting uncomfortably into the sun as you take the shot!

 

[Thomas71]

Might be worth reading the book "Fifty shades of gray"... better than take the measure of palm of the hand before and after a summer holiday...

 

[jeffreyg]

I decided to check my Home Depot paint chip theory. I tested a never used gray card, two acrylic gray cards, a Munsell gray scale and several of the paint chips. All were in a windowless room with 5500k lighting and placed on a small easel so they would be at the same angle. I used two different Pentax digital spot meters focused through the spot circle and used the same battery in each. All read the same or within less than one half a stop. The paint chip reading the same as Munsell and acrylic cards was the Behr Ancestral ppu24-05 but several others were very close less than a half stop. Since use Delta 400 no problem.
Not a scientific study but it was easy and the poster who was looking for the cheapest solution this might work since the samples are free.

 

[jeffreyg]

Since I use…. Sorry for the omission

 

[wiltw]

I decided to check my Home Depot paint chip theory. I tested a never used gray card, two acrylic gray cards, a Munsell gray scale and several of the paint chips. All were in a windowless room with 5500k lighting and placed on a small easel so they would be at the same angle. I used two different Pentax digital spot meters focused through the spot circle and used the same battery in each. All read the same or within less than one half a stop. The paint chip reading the same as Munsell and acrylic cards was the Behr Ancestral ppu24-05 but several others were very close less than a half stop. Since use Delta 400 no problem.
Not a scientific study but it was easy and the poster who was looking for the cheapest solution this might work since the samples are free.

The other part of the question 'which gray card' has to consider White Balance standard, so that folks shooting with the 'true gray card surrogate' card know if it yeilds proper neutral rendition in color photos.

I suggest that all the gray cards which you included in your density variation test be also submitted to a White Balance test. This can be readily accomplished

1. by photographing all with a digital camera set to a Daylight color balance,
2. then using the postprocessing software's Eye Dropper selection tool on the gray card in the photo to set 'neutral', and
3. then read the Kelvin temperature which was chosen to render that gray card to be 'neutral' in the photo

...different values resulting in postprocessing values which differ from the set WB value of the camera would indicate deviation from 'neutral'.
This can be done with a single photo in which all the cards are gathered and photographed.

 

[jeffreyg]

I use black and white film Delta 120 400iso and HP5 4x5 both at box speed and process with D76 or PMK pyro or occasionally Ilfotec. The light meters have the zone scales and the readings all came out to zone 7 or just past less than half a stop towards zone 6 This has worked well for me for some 50 years. When I rarely use color film I use an incident meter and don’t process myself if digital mostly family snapshots I let the camera do the setting either aperture or shutter speed depending on the situation I’m not sure filming all the gray cards together will work since they are different sizes and putting them on a background might influence the setting. I don’t have a macro lens so that part of the test might not be accurate Maybe someone reading these posts will try what you suggested.

 

[wiltw]

I use black and white film Delta 120 400iso and HP5 4x5 both at box speed and process with D76 or PMK pyro or occasionally Ilfotec. The light meters have the zone scales and the readings all came out to zone 7 or just past less than half a stop towards zone 6 This has worked well for me for some 50 years. When I rarely use color film I use an incident meter and don’t process myself if digital mostly family snapshots I let the camera do the setting either aperture or shutter speed depending on the situation I’m not sure filming all the gray cards together will work since they are different sizes and putting them on a background might influence the setting. I don’t have a macro lens so that part of the test might not be accurate Maybe someone reading these posts will try what you suggested.

I would be happy to do the test, for the benefit of the Photrio community, as it can be informative to all about how much (or little) they can depend upon impromptu 18% gray card surrogates for use with Color Balance accuracy. I used to use gray card as control, to have my color print maker achieve proper balance when I was doing product photography with film and the client was picky about color reproduction, for photos reproduced in catalogs.
I would simply arrange the multiple gray samples you have, side by side and take one photo of all, with Daylight balance setting on camera, and use Lightroom balance the image multiple times and note the selected Color Balance value when sampling each of the swatches in the photo.
Send me PM and I can send you my address for mailing your gray swatches, and I can return them all to you if you wish...only if you have any interest.

 

[jeffreyg]

Wilt. If you are near a Home Depot or a paint shop you can find them. The one that matched the best was Behr Ancestral ppu24-05. My guess is that other brands have similar swatches and may even have or will make sample bottles if that’s of interest.

 

[wiltw]

Wilt. If you are near a Home Depot or a paint shop you can find them. The one that matched the best was Behr Ancestral ppu24-05. My guess is that other brands have similar swatches and may even have or will make sample bottles if that’s of interest.

I have no idea what your criteria of choice for your test samples...for example why there was 0.5EV deviation from 18% gray card reading. I though a parallel test of same gray card selection, but used for Color Balance, would be valuable insight.
Perhaps if you simply list which samples (color number on card, brand paint) I could select same ones.

 

[jeffreyg]

I have no idea what your criteria of choice for your test samples...for example why there was 0.5EV deviation from 18% gray card reading. I though a parallel test of same gray card selection, but used for Color Balance, would be valuable insight.
Perhaps if you simply list which samples (color number on card, brand paint) I could select same ones.

I have no idea what your criteria of choice for your test samples...for example why there was 0.5EV deviation from 18% gray card reading. I though a parallel test of same gray card selection, but used for Color Balance, would be valuable insight.
Perhaps if you simply list which samples (color number on card, brand paint) I could select same ones.

I happened to be in Home Depot and selected twelve swatches that looked like they would be close to my existing gray cards. All were Behr Dynasty Marquee line: dawn gray, imperial gray, dawn, gray, imperial gray, antique tin, ocean swell, euro gray, lengandry gray, and the Ancestral ppi-24-05. I was just doing this out of curiosity to see if any matched the gray cards I have been using for years I thought reading with spot meters under constant illumination at the same angle would be interesting and see if my light meters agreed with each other. And since the original post was looking for a cheap gray card it might be an answer. You might want to do it more scientifically and give us all a better answer

 

[wiltw]

Thanks for the list of color names. I certainly can find thost Behr Dynasty Marquee names at my local Home Depot!

 

[Alan Edward Klein]

I happened to be in Home Depot and selected twelve swatches that looked like they would be close to my existing gray cards. All were Behr Dynasty Marquee line: dawn gray, imperial gray, dawn, gray, imperial gray, antique tin, ocean swell, euro gray, lengandry gray, and the Ancestral ppi-24-05. I was just doing this out of curiosity to see if any matched the gray cards I have been using for years I thought reading with spot meters under constant illumination at the same angle would be interesting and see if my light meters agreed with each other. And since the original post was looking for a cheap gray card it might be an answer. You might want to do it more scientifically and give us all a better answer

I bet the grays are all close except for when you shift the angle of illumination.

 

[DREW WILEY]

Jeffrey - the Pentax meter reads within a third stop. Combining that with up to half a stop off in your experiment, and it's a deal killer with color film, some b&w applications too. The Munsell system was never intended for this; and neither Behr paint or its chips are considered high-end. Even the best printed chips from professional brands have variations from printing to printing. Sure, you can substitute these kinds of things for casual purposes; but I wouldn't want to rely on them for any kind of fussy film work. ... And matching paint chips to gray cards on hand, which perhaps had even poorer quality control, might have faded, and vary one to another ...???

You get what you pay for : paint chips are free; serious gray references are not. I still have a variety of paint chip collections stored away from my architectural color consultation days, both domestic and Euro. In their highest quality printings, Benjamin Moore had full-page sized sheets of each color in a set big thick three-ring binders, with color sheet large enough to be an actual gray card, but available only to architects and other color professionals. They actually had three different levels of color chip printed quality, with the free store variety being the least, of course. But still, I'd never use any of them for a critical film test, but only the MacBeth chart, which is specifically designed for that kind of purpose.

 

[pentaxuser]

Yes, life is truly hard, Drew

pentaxuser

 

[Stephen Benskin]

I've noticed a repeating theme running through many threads here. How can one achieve accurate results when not following recommended methods. What follows is an endless discussion on how to MacGyver it. My response is generally why not just get the right equipment and use it correctly.

If you are concerned about accuracy, get a quality reference target and pay for it. Why compromise, wonder, and waste time wondering about it? Spend that energy using it for what it's meant for.

As we wonder about the subtle differences of paint chips, very little space has been given to two factors that are important even with a high quality gray card. Lambert's cosine law (Cosine law of Illuminance), which according to Wikipedia states, "the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle θ between the observer's line of sight and the surface normal; I = I0 cos θ." And the directions Kodak includes with their gray card"

This alone is a 1/2 stop question that no one seems to care about. The statement is saying if an 18% gray card is properly metered, the correct exposure for a normal scene is 1/2 stop more than what the meter indicates. Maybe the topic is just not as interesting as discussing the amount of melanin.