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lordplavis · 1 year ago

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Please tell me about autochromes

Oh it's such an interesting process of creating colour photos with sososososo incredibly simple yet so clever and amazing means.

But to explain I need to go back to the beginnings of photography (no I don't have too but I like to nerd out) .

The first photographs were taken on glass or metal plates coated with light sensitive chemicals (you wouldn't belive how much I'm oversimplifying here). The problem was that these early plates were only sensitive to blue light which created really striking albeit not completely lifelike photos.

These plates were not really light sensitive (around iso 0,5-1,5) and to increase that sensitivetie people started making plates sensitive to more and more of the light spectrum.

Now we have the capability to store every colour but only as a general brightness of all colours of the light (oversimplified)

At some point then people realised that human vision works via red green and blue receptors and thought "hey what if we did that just with photographic plates"

And that's how the tri chrome colour process created the first colour immages.

These had some major problems though. Because you had to take three pictures with different coloured filters.

So you couldn't take photos of anything that moves. You also needed three photo plates per immage and In addition to that you could only really view the immages by projecting the three immages with red, green and blue light (or other processes too complicated to be practical) .

In comes the auto chrome process.

The auto chrome process takes basic black and white chemistry and makes a colour slide out of it.

By the magic of the potato!!!!

I'm not joking.

The technique uses ultra fine granules of red green and blue coloured potato starch deposited ontop of a black and white glass photo plate.

So if you take the photo each spot under a color particle only gets light from that colour.

(just like the colour mask ontop of a digital sensor)

That means every coloured dot stores the brightness information of that specific colour in that spot.

So if you then develop that plate as a positive immage you can hold that plate up to the light and the light gets coloured by the starch particles and the brightness of each colour sploch is determined by the black and white immage.

And by that technique you get a colour immage.

It's ofcourse not ideal because all that coloured starch takes a lot of the light away when taking and viewing photos.

But still it enabled people to take amazing colour photos.

For example...

These pictures of Christina O’Gorman taken by her father Mervyn O’Gorman are over a hundred years old.

They are not colourised. They were taken like this in 1913.

These immages made by basically using a rgb 'grid' glued to a simple black and white photo plate made incredible photos possible.

And that's why autochrom is just an amazing thing.

If you're interested in learning more details...

technology connections made a really interesting video about this technique where its probably explained way better than in my fascinated nerd rambling.

youtube

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xtruss · 8 months ago

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Photography: It’s Harder Than Ever To Identify A Manipulated Photo. Here’s Where To Start.

To Protect Yourself from Misinformation, Experts Suggest Analyzing Everything From How a Photograph is Lit to Where You’re Getting Your Information in the First Place.

— By Allie Yang | March 12, 2024

In one of the earliest examples of photo manipulation, the head of Abraham Lincoln is superimposed on the figure and background of an earlier print of John C. Calhoun. For almost a century, no one noticed the image was modified—until photojournalist Stefan Lorant noticed Lincoln's mole was on the wrong side of his face.Composite Print By William Pate-Courtesy Library of Congress

After months of speculation about Kate Middleton’s absence from public life, a digitally altered family photo released by Kensington Palace only fanned the flames as eagle-eyed observers identified details like a strange cuff and mismatched zipper.

Though the Princess of Wales later admitted to editing the photograph, experts say most times you should leave image verification to the pros.

The Original Print of the Engraving by A.H. Ritchie of John Calhoun, Circa 1852. With the help of modern reverse image search, it's easy to find information on past iterations of images like this one. Print By Alexander Hay Ritchie-Courtesy Library of Congress

“It's very easy to go way too far here and suddenly everything is suspicious,” says Hany Farid, a professor at University of California, Berkeley, who specializes in media forensics. “By eye, you’re not going to be able to figure out what's real with any reliability whatsoever.”

Meanwhile experts have special tools, including “digital forensic techniques and resources like geolocation, satellite imagery, and sensor data to make sure we—and our audience—can trust what we’re seeing,” says Christopher Looft, coordinating producer of the visual verification unit at ABC News. “Generative artificial intelligence is advancing at such a rate that the ‘tells’ we’d look for a year ago are probably out of date by now.”

That said, if you’re worried about being misled by misinformation, these are some tips that experts say you can start using today.

What’s The Source?

Your first line of defense is questioning where a photograph comes from. Something posted by an individual, a business, or a political entity might be altered to make them look good, promote a product, or otherwise benefit them.

But what about trusted news outlets, which are businesses too? Farid says you can still rely on those with a history of objective coverage. “They're incentivized to get it right,” he says. When photo agencies had to notify customers to stop distributing the Kensington photo, it was “bad for business” as it hurts their credibility, Farid says.

“Ninety nine point nine percent of the time they get it right,” Farid says of trusted news organizations. “You may take issue with any perceived political bias, but these are serious people doing a serious job.” He adds that the standards these outlets must meet for publishing a photograph are far and above those of any an individual or commercial entity, if they have standards at all.

Beware of Hot Topics

Political fakes also run rampant, particularly in election years. There’s satire, Farid says, which is protected as political commentary—then there are robocalls using a presidential candidate’s voice, which could be illegal. It’s a fine line.

Conflicts are another charged topic. “In the fog of war, it's very hard to figure out what's going on. Emotions are running spectacularly high. And so infusing that with disinformation, fake images, makes things very messy,” Farid says. “Within days, we see fake images, fake audio, fake video, and then the real thing is being claimed as fake.”

Think About Lighting

One of the ways you can tell the Kensington photo wasn’t manipulated by AI is that “the lighting on their faces is consistent,” Farid says. It’s a detail that Mark Thiessen, a National Geographic staff photographer, is constantly thinking about.

He was able to answer which cheetah photo was generated by AI—a riddle that stumped many on our staff and our readers—thanks to decades of experience in lighting and photography.

Thiessen notes that while the two real photos had realistic lighting—one ambiently lit by the sun slightly to the right of the cheetah, the other captured with head-on flash—the AI cheetah had an unnatural, strong blue highlight in one eye. Blue isn’t necessarily a strange highlight color, especially outdoors when the eyes reflect the sky, but without any other blue hue in the picture, he says this was a dead giveaway.

“The photographer who taught me lighting back in college told me to look at every image and figure out how it’s lit—every movie scene, magazine shoots, commercials,” Thiessen says. “You can figure out how things are lit generally when looking at the eye—it’s reflective and round, it’s like a mirror of the lighting setup.”

Fact Check Yourself

If you see a photograph that’s giving you pause, Farid suggests searching to see if any research or articles have been published about it, or if other outlets like Snopes or FactCheck.org have investigated it. If you’re only seeing the image on community forums like Reddit, 4chan, and Twitter “you should probably just ignore it.”

“Many so-called ‘fakes’ aren’t necessarily fabrications, they’re just old images misleadingly passed off as new,” Looft says. “Reverse image search is an easy way to tell whether an image already exists. There are many options but TinEye has a great reverse search, and some other tools for those looking to go a little deeper.”

The Bigger Picture

The distinction between “photojournalist” and “photographer” has always been an important one, Thiessen says. For photojournalists, the content of the photo cannot be changed.

There’s a difference between standard editing practices—such as adjusting contrast levels from a raw file—and manipulation. Instead of shooting an object suspended by a fishing line and editing out the fishing line later, he says, “we’d figure out how to shoot it without a fishing line.”

When it comes to marketing or commercial use, however, those rules can be bent to allow editing in post-production. And as the line between promotional and editorial journalism in imagery becomes blurrier than ever, Thiessen says the delineation of photojournalism is critical.

Rather than relying on a handout from the royal family, or a brand, or anyone else that has their own interests, it’s all the more important to have photojournalists we can trust not to manipulate photos. Even better, he says, is to have several independent journalists attending the same event so they can check each other.

“If we erode trust in the very institutions, the media and academics and the scientists and the government, we are in a lot of trouble as a society,” Farid adds. “Because when that happens, the very mechanisms that we have to talk about a global health crisis, global climate change, elections, integrity, are gone.”

#Photography #Documentry Photography #Photography Techniques #Innovation #Information Technology& Telecommunications #Immaging Technology #Manipulated Photos #Harder to Identify #Misinformation #Experts’ Suggestion #Analysis #Source #Hot Topics #Facts Checks

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vehrec · 3 years ago

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The whole company town thing keeps coming back again and again, because every time you call someone a ‘Visionary’ and a ‘Great Man of Business’ they get delusions about their ability to fix society. Pullman Illinois, where workers couldn’t own their houses, and the Boss controlled the library’s books, and there were no town meetings of any kind. Oh, and in response to an economic downturn, he cut the wages, but left rent the same. Fordlandia, that’s another good one, Henry Ford trying to build a titanic rubber plantation in the middle of the Amazon rainforest, and building it in the immage of the american midwest. Probably had mandatory squaredancing, when he wasn’t forcing people to eat in his cafeteria. And Epcot, or rather, EPCOT, the Experimental Prototype City Of Tommorow. Walt Disney wanted to build a city, a real city. Urban center, factories, suburbs, the whole shebang. A city without visible trucks, strongly seperated car and pedestrian areas, the houses all the very latest technology. But uh, nobody would be allowed to vote to change anything without permission. Because, in the end, the Company Town isn’t only about making money, it’s also a statement of control. It’s an opportunity for the cooperate stiffs to tell you how to live your life. And trust me, the evidence of history says they don’t want it any more messy than your worklife.

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aqozatechnology · 2 years ago

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Why Corrosion Monitoring In Data Centres Is Important?

Corrosion monitoring plays a very important and vital role for any electronic equipment throughout its lifetime. It is essential to understand the working environment of the data center or a critical control room so as to implement a monitoring and control solution that suits its requirements. New changes made in manufacturing due to regulation have made electronics more sensitive to corrosion than ever.

In this article, we will see why and how corrosion monitoring is implemented for data centers and control rooms, and its importance.

Why corrosion monitoring?

It is important for the equipment to operate in a safe environment for optimal functioning and a long service life. Electronics present in a dynamic environment mean that the severity of contaminants present can vary from time to time. A single opening and closing of a door can introduce contaminants that can ultimately lead to equipment failures. The major reason for corrosion monitoring is to monitor the contaminants inside and to classify the severity of the working condition. By doing this we can take necessary measures to prevent corrosion.

Corrosion monitoring will classify the region into G1, G2, G3, and GX based on severity ranging from mild to severe respectively. Once the class is identified, we can select an appropriate corrosion control technique. Corrosion monitoring can be further used to check the efficient performance of the corrosion control unit, that is, if a corrosion control unit is equipped and functioning then the corrosion monitor should be indicating a corrosion-free environment.

How is corrosion monitoring done?

Corrosion monitoring is done by measuring the reactivity of sensor metals in the working environment. It gives us a brief picture, how much reactivity the sensor metals showf proper corrosion management is absent.

The majority of metals used for sensors are copper, silver, and gold. And based on the reactivity of these metals we can find the class, severity, and conclusions as shown below;

Class

Severity

Copper reactivity(Å)

Silver reactivity(Å)

Comments

Mild

<300

<200

Corrosion is not a factor in determining equipment reliability

Moderate

<1000

Corrosion effects are measurable and corrosion may not be a factor, Enig and ImmAg PCB surface finish failures

Harsh

<2000

High probability the corrosive attack will occur. OSP and ImSn PCB surface finish failures

Severe

>2000

Only specially designed and packaged equipment to survive

The metals can be used as a passive coupon sensor where they are exposed to a minimum of 30 days and then taken to a lab for analysis, or as an active sensor that gives real-time information on corrosivity. The sensors might work on different techniques to measure reactivity. Please refer to the article- what are the best corrosion monitoring techniquesto know more about it.

At AQOZA technologies we offer both passive and active corrosion monitoring units to choose from based on your requirement. Being a specialist vendor in gas phase filtration and monitoring, AQOZA offers optimum performing corrosion control units to various industries. Get in touch with us to know more!!!

#corrosion monitoring units #corrosion control units

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