Color Science and Teaware Photography

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karma
Posts: 160
Joined: Fri Feb 28, 2020 2:14 pm
Location: Texas

Sun Mar 29, 2020 11:27 pm

Or why you can’t trust pictures even if they’re ‘honest’

So in my time shopping for a first yixing, I’ve realized that at least some of the advice I’ve received has been faulty — even though I know little about yixing pottery. Frequently, as the title suggests, people who I trust very much have mentioned that the color of a pot indicated something — usually negative — about the clay a teapot is made from. Because I know very little about yixing pots, and they know a great deal more than me, I believe them and defer to them.

However, I know a great deal about digital photography, color science, photoshop due to my experience as a colorist for movies and commercials, and I’ve also done product photography and videography for some tea shops. You’ve probably never seen my work and there are plenty of people know much more than me, but what I know is enough to help people in this hobby maybe be a little less wrong on some things. I don’t think I know enough to know if this write up will actually help those of you who know a lot about yixing pots.

A Brief Summary of How You See Color

Our eyes use two main kinds of cells — called photoreceptors — to process light: rods and cones. You have a lot more rods than cones, and out of the 125 million photoreceptors in your eyes only 5 million are cones. Rods can’t see color but they do see light and shadow; cones see color, but only one color each — red, green, or blue.

Each of these cones responds to a different wavelength of light and your brain interprets all the combinations of these receptors as the countless colors you see. These 3 different, specific wavelengths of light also correlate to different energy levels of light. A photon that punches so hard triggers your red receptors, then your green, then your blue, etc.

However, while the photons hitting your retina have some amount of absolute ‘color’ your brain doesn’t just report what you see. Have you ever noticed how light bulbs in your house, in the subway or office, and the sun are all different colors? Go check — I bet you can find all different sorts of colors — they’re all “white” but all a little tinted. When you’re in colored light, unless it’s particularly egregious, your brain does a pretty good job of normalizing it so it all looks above board. Kind of like how you don’t see your nose.

Cameras on the other hand aren’t as smart as we are...

How Cameras See Color

Cameras work almost exactly the same way. Both digital and color film cameras both have analogs to photoreceptors (pixels or grain) that look for red green and blue light, record it, and allow us to view the image later.

However, cameras can’t just look for light and display it back — they have to process it in a way that looks like human sight. Camera sensors aren’t perfect replicas of the human eye, and some look for slightly different wavelengths of light to call “green” or don’t respond as brightly to the color red as they would (it’s the lowest energy after all!), etc. and every sensor has its own problems. Also, cameras try to compensate for how the human eye sees different “white” lights with something called white balance, which is the camera analog to your eye getting used to the light and seeing the “true” colors.

Ultimately, the camera processes the data it receives as 1s and 0s and keeps it like that until you want to look at it. However, because our brains mostly see light and shadow, your camera actually throws out a lot of that color data - compressing otherwise enormous files into something it can better work with and display for you, which brings us to...

How Screens Show Color

Believe it or not screens aren’t perfect.

They’re made up of millions of red green and blue pixels just like your camera sensor, but just like your camera the pixels aren’t 100% the same across all screens. Some red pixels are a little more red than they should be, etc. Screens are also backlit, which means they have a light behind them making the pixels shine at your face. Of course those backlights are different colors. To make matters worse, screens have a tendency to drift and backlights have a tendency to change from one bulb to the next. MacBooks are famous for drifting blue over time.

Companies pay people way smarter than me to design software which tries to compensate for these differences and “manage” colors. It also does things like interpret just how bright a certain value is, based on how bright the screen CAN go, how bright it is, and any other impacting factors. At my job our software even compensates for light spill within the room to try to make it as true as possible.

I’m sure by now you can see where this is heading but, essentially: the light entering through the lens (which, by the way, can also change the color! Ugh!), to the camera sensor, being processed into an image, displayed on a screen, and processed again by your eye... there’s a lot to make color change. Prints are even worse, and this is a best case scenario where we aren’t looking at image hosting sites, ISP side compression algorithms, or NightShift settings, etc.

By now I know what you’re all saying:

What Does This Matter and Why Do I Care?

Honestly I’m not sure it really does. I’m kinda new.

However, in the west, it seems like when it comes to sharing knowledge of yixing and the different clays and what’s “fake”, a lot of it comes back to photo records and scanned books. Comparing your pot to pictures of other peoples pots confirmed to be real, looking at photos/close ups of real clay in books or on sites like mudandleaves, and sharing pictures of pots you’ve bought with your betters who tell you what they think. All of these do a great service to the community, and this definitely isn’t some sort of “call out” post.

You can probably tell whether something is hongni or Zini or duanni. You can look at the texture of a clay to get a good idea of what a clay actually is — but unless it’s a close up (and not digitally zoomed in on) I wouldn’t trust the color of it. You can look for the other types of dating, like shape or style or craftsmanship. There’s a lot that people can tell from images.

However, when we look at subtle things like color to determine whether a pot is low fired or high fired, the age or type of Zini, if a clay is dyed, the difference between Zhuni and hongni, or even, on some more subtle cases, if color variation indicates NZWH — I think it’s super important to be mindful of how impossible this is to judge online. The image you are seeing goes through a dozen different tweaks and alterations to the color and contrast of the image. I bet I could photograph a high fired pot and a low fired pot to look pretty similar, and with the right lighting I could hide that a pot was NZWH from you if it doesn’t have brush strokes etc. — these are all little things that could happen accidentally, just based on what camera you choose to shoot with.

I don’t know if the community already knows all of this — I know people say you can’t really judge a lot about a pot from a picture. But I figured it was a good idea to give a basic resource for understanding what photographs are good at showing us and what we should be more cautious of.

Isolation cabin fever made this post way longer and more technical than it needed to be. TLDR: don’t trust the colors of photos, trust the shapes in them.
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Bok
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Mon Mar 30, 2020 12:11 am

Very nice write up! I encounter these things as well in my daily job, plus more the print side of it. It’s very treacherous to judge by pictures.

But- if you’ve seen enough images and the real thing and account for all the above said, one can still pretty good conclusion in many cases. Not to a fault, but enough for a basic conclusion.
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Bok
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Mon Mar 30, 2020 1:02 am

Sometimes it also helps if one can compare images from the same source, but of different pots to determine what corrections int tone one has to account for.
karma
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Mon Mar 30, 2020 1:13 am

Bok wrote:
Mon Mar 30, 2020 1:02 am
Sometimes it also helps if one can compare images from the same source, but of different pots to determine what corrections int tone one has to account for.
While that can certainly help, enough vendors use cell phones or have varying setups (Chen, Jay, Emmett...) that any sort of comparison is largely theoretical. Unless you're using a prosumer camera with a light setup (or get lucky with the outside sky), even between photos of the same pot you're going to get the sort of color variations that could determine high vs low fired or modern vs vintage clays. I think you experienced this on a post recently.
Noonie
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Location: Ontario, Canada

Mon Mar 30, 2020 1:33 pm

@karma - thanks for posting this, it was very interesting.

I really liked your ending though "Isolation cabin fever made this post way longer and more technical than it needed to be. TLDR: don’t trust the colors of photos, trust the shapes in them." For one, completely agree with isolation fever and spending more time on things we may have otherwise skimmed over; though not always a bad thing. And trusting the shapes, good advice!

A couple of times in my life I was pretty big into photography, I would take 100's (back when film) to 1000's of shots on a vacation, going out of my (our) way to see sights that I thought would make good photos. I've since moved away from that line of thinking and now I intentionally avoid photographing something that catches my eye, as I prefer to use all of the time available while the light is just right, to take that mental and sensory image. That said, it is still fun catching something cool in a photo and being able to inspire someone to 'get out there' and see it for themselves. Sometimes easier said with a picture than an explanation.
karma
Posts: 160
Joined: Fri Feb 28, 2020 2:14 pm
Location: Texas

Mon Mar 30, 2020 6:10 pm

@Noonie

In my experience, except for utility, photographs are best used as a thing unto themselves like a painting or a sculpture. When I was an active shooter I’d spend 20 minutes to an hour (once or twice, even days) on just one shot. I agree: thinking a photo will preserve the moment often leads to the moment slipping by and you wondering where it went.
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