White Balance....white, gray, and black WB cards.

[table1349]

Simple, it's called experience.

It was a rhetorical question, to highlight the fact that the answer is not "plastic cards"

Where I come from it's called taking just to hear yourself talk, or in this context, it's typing just to see what you typed.

 

[WayneF]

>An 18% tone is dark.

I think you are confused. 18% has nothing to do with dark or light. 18% refers to the percentage of photons that reflect off of the surface. Whether that surface is light or dark is entirely then based on how many photons there are hitting the surface, and the reflectances of other objects in the scene.

Was that to me? You've never seen an 18% card? I would have guessed you had, but yes, they are in fact dark. 18%.

18% has nothing to do with any other objects in the room. The 18% card is assumed to reflect 18% of the light that hits *IT".

An 18% reflectance surface in a room full of 2% reflectance surfaces would be bright white.
An 18% reflectance surface in a room full of 90% refelctance surfaces would be dark black.
An 18% reflectance surface in a lush grassy field (around 20% reflectance) would be almost perfectly neutral gray.

I guess you are saying something like that the moon's surface albedo reflects only 12%, yet the full moon looks bright in the black sky. Interesting, but of course, this has nothing to do with the WB subject. Why these tangents?

Presumably, 18% was chosen due to some ancient guess or research or who knows that suggested that the average reflectance of "typical" scenes in the world (or perhaps the central anchor point of our eye adjustments for "typical scenes") is around 18%. However, I've never seen any data or actual scientific reasoning behind this, so in reality it's mostly just an arbitrary number that is neither dark nor light nor right or wrong particularly. Just a number.

But it's "supposed to be" about 50th percentile reflectance compared to... some sort of average of something.

That is a long story, about that the human eye is not linear, believed to perceive it as middle gray (the brain does many things to fool us). The 18% card actually started trying to calibrate printing press ink to half tone screens before photography. But for photography, Ansel Adams felt sure his Zone V was 18% in the 1930s, matching our brains perception, etc, etc. But of course, relative to average scenes, today our meters are 12.5%. Some people (confusing digital with analog) even try to calibrate light meters to an 18% card, but gamma in the histogram is all that puts 18% up near center - it is not a large error, but of course, camera auto exposure tries to puts any value near the center. But again, none of this has nothing to do with the subject of WB. That subject is WHITE Balance. Gray can work, but white is the way I would bet.

 

[Gavjenks]

Have you ever seen someone using a proofing booth? Holding an image of the product next to the product to make sure the colors match? It's likely you haven't.

The fact that I haven't is precisely why that system makes zero sense. Your customers are not using or buying your products inside of proofing booths. They are buying them in stores with variable lighting and context, and using them in wildly varying environments that look absolutely nothing like a proofing booth...

If I'm going to get upset about my skis, it will be because they don't match the tones in the ad when they are on the SLOPES, not because of how they look in a proofing booth that I've never set foot in and will never look at the skis in...
If I'm going to be upset about my curtains, it will be because they don't fit in my LIVING ROOM like I thought they would, not a proofing booth that I've never seen.

Aren't you glad the art directors and photographers took the time to ensure the products were accurately represented so that when they showed up at your house you got exactly what you were expecting?

No I'm not glad, because this has pretty much never happened in my life.
My shoes never look remotely as white as they do in ads
My packaged food never looks remotely as vibrant as it does in ads
Most of the furniture I have looks significantly darker than I thought it would when I bought it, because my landlord has super bright walls and won't let me paint.
My cellphones aren't as shiny
etc.
etc.

Hell, forget catalogs! It doesn't even work out when I'm looking at the most highly potentially controllable product in the world, with my own two eyeballs, in a store in person: paint. When I go to the hardware store to pick out paint, generally I STILL have to bring the swatches home with me and hold them up in that environment to see if they match anything. What chance do products in a catalog stand, if paint can't even be controlled in person? None. All you can ever do is ensure relative accuracy between your own catalog's products.

I guess you are saying something like that the moon's surface albedo reflects only 12%, yet the full moon looks bright in the black sky. Interesting, but of course, this has nothing to do with the WB subject. Why these tangents?

I didn't say it did have to do with WB.

I'm talking about tonality, and for tonality, yes, the moon thing is a great example of what I am talking about. If you used a set of control cards to shoot a photo of the moon, and then put it in a magazine according to those standards, it would not look anything like the moon actually looks. Which is nothing but a more dramatic example of any other product that is used anywhere other than inside of photography studios or proofing booths.

 

[TreeofLifeStairs]

My cellphones aren't as shiny etc. etc.

I guess you don't have an iPhone.

 

[Scatterbrained]

Have you ever seen someone using a proofing booth? Holding an image of the product next to the product to make sure the colors match? It's likely you haven't.

The fact that I haven't is precisely why that system makes zero sense. Your customers are not using or buying your products inside of proofing booths. They are buying them in stores with variable lighting and context, and using them in wildly varying environments that look absolutely nothing like a proofing booth...

If I'm going to get upset about my skis, it will be because they don't match the tones in the ad when they are on the SLOPES, not because of how they look in a proofing booth that I've never set foot in and will never look at the skis in...
If I'm going to be upset about my curtains, it will be because they don't fit in my LIVING ROOM like I thought they would, not a proofing booth that I've never seen.

Aren't you glad the art directors and photographers took the time to ensure the products were accurately represented so that when they showed up at your house you got exactly what you were expecting?

No I'm not glad, because this has pretty much never happened in my life.
My shoes never look remotely as white as they do in ads
My packaged food never looks remotely as vibrant as it does in ads
Most of the furniture I have looks significantly darker than I thought it would when I bought it, because my landlord has super bright walls and won't let me paint.
My cellphones aren't as shiny
etc.
etc.

Hell, forget catalogs! It doesn't even work out when I'm looking at the most highly potentially controllable product in the world, with my own two eyeballs, in a store in person: paint. When I go to the hardware store to pick out paint, generally I STILL have to bring the swatches home with me and hold them up in that environment to see if they match anything. What chance do products in a catalog stand, if paint can't even be controlled in person? None. All you can ever do is ensure relative accuracy between your own catalog's products.

I guess you are saying something like that the moon's surface albedo reflects only 12%, yet the full moon looks bright in the black sky. Interesting, but of course, this has nothing to do with the WB subject. Why these tangents?

I didn't say it did have to do with WB.

I'm talking about tonality, and for tonality, yes, the moon thing is a great example of what I am talking about. If you used a set of control cards to shoot a photo of the moon, and then put it in a magazine according to those standards, it would not look anything like the moon actually looks. Which is nothing but a more dramatic example of any other product that is used anywhere other than inside of photography studios or proofing booths.

Do you only view a catalog in a store? Normally you view them at home, in your own lighting. The point is to have as accurate a representation as possible. It's like the old grapevine analogy where you say something at one end to see what is said at the end. If you don't care about accuracy on the front end, by the time it gets into the hands of a potential consumer in their home there's no telling what it will look like.

Let's use your paint swatch example. Does the swatch match your wall after using the same paint on the wall? How would you feel if it was several shades off because someone cared as little about accuracy as you do? If someone thought, "it's pointless to make this swatch an accurate representation of the paint because who knows what the customers house will look like. . . . " then you take the swatch home, compare it, buy the paint, only to have the paint be several shades off. But I guess it doesn't matter does it?

 

[AlanKlein]

People who use ETTR apparently have the same misunderstanding as people who overexpose their negative film. They do what they do to get more details in the shadows. The problem that I have seen with film is that colors shift even if you can use an overexposed negative for a final print.

I usually bracket my landscape shots. Often I can use all three to get an acceptable print, especially with film like Portra that has a wide range of exposure. But wh en I compare colors, there are differences among all three bracketed shots. Color and saturation shifts as the exposure changes. They are not the same among any of the three photos. For landscape shooting, it probably doesn't matter much because it's close enough so when you look at just one of them, it seems perfectly acceptable. However, if you shoot clothing or art, missing the exposure is going to get you photos whose colors will be unacceptable to manufacturers of the product and artists of their paintings. If you order a red shirt from a product catalog, and the one you receive is maroon, you're not going to be happy and will return it.

 

[Gavjenks]

Let's use your paint swatch example. Does the swatch match your wall after using the same paint on the wall? How would you feel if it was several shades off because someone cared as little about accuracy as you do?

I have agreed all along and repeated in every post that it is worthwhile to match your own products relatively to one another.

Do you only view a catalog in a store? Normally you view them at home, in your own lighting

Okay, yes, for catalogs in print, lighting in particular on the item itself has a single solution: the ink having the same reflectance as the actual material = correct. However,

1) The same cannot be accomplished with monitors, since people do not have calibrated monitors. It has the same optimum solution as ink, but is not possible to achieve or even to maximize, since nobody seems to know what the average consumer actual monitor settings are. I made a thread asking about this awhile back, in fact (the issue of trying to determine actual average monitor profiles of real consumers and citizens in general), and nobody seemed to care or have any idea of any research on that.

2) Even if you can accomplish it, like with the catalogs, you still have an issue of contextual reflectances. E.g., if your catalog shows a walnut table next to a fairly dark orange wall, and my wall is white. The exact luminance on the page in the portion where the table is printed may very well match the luminance coming off the table in my living room, but it will still not look the same in situ as I expect it, because we accoutn for surroundings in complicated, nonlinear ways. Similarly, I have to bring paint swatches home in order to hold them in their surrounding furniture and drapes and carpet and blah blah to see how it fits context. Not so much because of the light.

You could do something like have a closeup of the product that bleeds right off the edge of the catalog. Or I could fold the page so it goes through the product, and hold it up to the area in the room where I want to put it. But I've never seen anybody print like that, or anybody do that (except fruit of the loom or land's end types of things where admittedly they do put the various color options bled out to the edge of the page usually. It is a rare exception, and I doubt most people use it in the aforementioned way.)

For a concrete example, my shoes don't look as white, even if we pretend my monitor is perfect for a moment, because you mightshow them on weird dark black glass tables, for example, that I don't walk on, thus making them appear whiter by contrast:
http://www.afew-store.com/bilder/produkte/gross/Nike-Rosherun-Canvas-Schwarz_b2.jpg

In the above case, advertisers are promably doing this on purpose. To highlight whatever they want to hawk the most about their product. But even if you aren't intending to, you still have to choose ONE context for an image. Which do you choose?
Put the shoes on black? They oversell their whiteness.
Put the shoes on white? They undersell their whiteness.
And nobody's gonna put them on sexy sexy gray... (and even if you do, you're still overselling to some who have white floors and underselling to others who have dark floors)

 

[DSRay]

The point is he's asking more than one question and your response is a very limited one. In addition to talking about white balance you need to address the purpose of the white and black cards and not just say you don't know why you would use them. You tech people are great at minutia but suck at real answers.

 

[bronzeo]

Using a histogram seems useless to me when shooting artworks.... When shooting other outdoor shots, portraits, etc, you usually have some common "look" that you are trying to achieve. Because artworks have such a wide variety of high to low contrast, high to low color key and sometimes many variables on one canvas, I am forced to correct as much as I can at the studio level and then do all other corrections by eye, for which I have trained myself pretty well. Prior to publishing via inkjet I have spent many hours press-side at the printers making color volume calls... I suppose a histogram is similar to the use of a densitrometer used in printing, which I did better work eyeing the prints..... That said watching a histogram might help with my other shots, and would love to learn more about it.

 

[Gavjenks]

The value of a histogram is minor in the field, IMO. It serves two purposes:
1) Making sure you didn't clip or aren't effectively so close that you may as well be clipping. This is necessary no matter what methods you're using. Clipped data is useless data, regardless of your method of choosing exposure.
2) Making sure there isn't a huge swath of the histo that is being unused, in which case you probably want to re-evaluate lighting or exposure (ETTR is one example, but even if you're not doing that, dramatic empty areas are still informative. This one I would also say is almost universally useful, although apparently it is somewhat controversial (because even if you want a dark photo, capturing it at a full exposure gives you that option + more options on top of it later on), as somebody in this thread claimed that pulling down exposures later introduced some alleged issues.

And [3, if following that other guy's advice:] aligning control values like from cards to certain parts of the histo would be another use for it, if you have been convinced you want to do that.



But trying to do things like judging the subtle shape of the histo is not terribly useful in the field, because as you point out, there isn't really any "correct" shape, and it's difficult to just judge artistic qualities of a photo from a histogram by eye.