Table of ContentsTable of ContentsWhat is a lumen, anyway?Different types of lumen measurementsThe problems with the standardsA huge focus of the AV world has been on brightness, and for good reason. Without an adequately bright image, especially in a room awash with ambient light, your displays picture will look washed out and seeing detail is difficult. With projectors, the amount of brightness it can produce will also determine how big of an image it can project.Brightness is also one half of contrast (the other being black level), which is the most important aspect of a picture because of the way our visual system developed to survive in the world. While the amount of brightness a TV or projector produces isnt a life or death situation (as much as we video reviewers think it might be), its important that we know what were getting from a product were looking to buy. Unfortunately, that isnt always the case.Recommended VideosLets take a look at what these specs actually are, and how to make sure youre getting the most out of them.RelatedDerek Malcolm / Digital TrendsYoull come across different terms as you read about brightness performance of displays both from reviews and manufacturer specs. Our goal as reviewers is to provide you, the reader, with an accurate representation of how a product performs in the real world as opposed to what the specs say. (Specs can be useful, but it doesnt mean theyre always entirely accurate.) So whats the difference between a lumen, a nit, a lux, and a foot lambert?Lumens (lm): The amount of visible light emitted by a source in all directions. Its used to measure the light output of projectors and bulbs. Since lumens are the measure of light from the source, they dont include screen reflectivity.Lux (lx): We sometimes see lux in relation to projector measurements. Its a measure of illuminance, or the amount of light that falls onto a surface. Specifically, one lux is one lumen per square meter.Nits (nt): Digital Trends readers are likely most familiar with nits as a unit of brightness measurement. We use this in the measurement of TVs and other panel displays (like monitors). Like lumens, nits is a representation of light emitted from a display, but from a single direction and not all directions. This is also sometimes referred to a cd/m2 (candelas per meter squared).Foot-lambert (ft-L): This isnt seen as much in the consumer space, but is another form of luminance measurement, like lumens and nits. Its used by the Society of Motion Picture and Television Engineers (SMPTE) to set brightness standards for theaters.When it comes to pure brightness capability of a projector, lumens is the important number.When you look at different lumen measurements that projector companies might use, not all are created equal. Theres ANSI lumens, ISO lumens, CVIA lumens, LED lumens, and just plain old lumens. So which ones are the best to pay attention to?Both ANSI lumens and ISO lumens are standardized through different organizations the American National Standards Institute (ANSI) and the International Standard for Organization (ISO). The specific ISO standard is ISO21118. There are claims of an ability to convert one to the other (an AWOL Vision blog post points to a 1 ANSI to 0.8 ISO comparison, while an Anker Nebula post uses 1 ANSI to 1.045 ISO), but there is no official conversion. In my experience, the two are very similar, and close to a 1:1.Phil Nickinson / Digital TrendsANSI has been the primary standard, although many companies and websites are switching over to the ISO standard. CVIA lumens are another standard created by the China Video Industry Association, but has not caught on worldwide yet.LED lumens are used specifically by LED projector manufacturers, but are not a standardized form of measurement. The reasoning behind those companies using the term is that the light from LEDs looks brighter to our eyes than measurement equipment. So the LED lumens number is the estimatedThe lumens landscape was the wild west for a long time and to some extent still is. Epson has spent time and money trying to fix this with lawsuits against companies that Epson claims are falsely advertising brightness output including Anker, AWOL Vision, JmGo. So now that we have standards everything is fine and totally accurate in the projector lumen world, right? Well, not exactly.Even with the standards, a projector can be considered within spec but still be up to 20% under the number that they publish. That means a 2,000 ANSI lumen projector could actually put out 1,600 lumens and be considered all well and good.Add to it that the lumens numbers posted by manufacturers are almost always with the projector in its brightest mode usually Vivid, or Dynamic, or something with a closely related synonym. The problem with these modes is that they arent generally color accurate, and often have a green tint to the picture. If you switch the picture mode into Movie or Cinema (which you absolutely should), you can expect a lower lumens output. Sometimes by as much as 50% of the published spec.Taking all of that into account, having the standardized forms of measurements are still incredibly useful and worthwhile to pay attention to. Companies are more accurately reporting what their projectors are capable of and reviewers are holding them to it. Finding third parties that have done scientific measurements is a great way to check what youre actually getting out of a projector instead of just believing what a manufacturer says. Just keep in mind that even then, what you get on your screen might not be whats listed on the box.Editors Recommendations

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See you on the dark side of the moon Beyond RGB: A new image file format efficiently stores invisible light data New Spectral JPEG XL compression reduces file sizes, making spectral imaging more practical. Benj Edwards Mar 28, 2025 6:11 pm | 1 Credit: MirageC via Getty Images Credit: MirageC via Getty Images Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreImagine working with special cameras that capture light your eyes can't even seeultraviolet rays that cause sunburn, infrared heat signatures that reveal hidden writing, or specific wavelengths that plants use for photosynthesis. Or perhaps using a special camera designed to distinguish the subtle visible differences that make paint colors appear just right under specific lighting. Scientists and engineers do this every day, and they're drowning in the resulting data.A new compression format called Spectral JPEG XL might finally solve this growing problem in scientific visualization and computer graphics. Researchers Alban Fichet and Christoph Peters of Intel Corporation detailed the format in a recent paper published in the Journal of Computer Graphics Techniques (JCGT). It tackles a serious bottleneck for industries working with these specialized images. These spectral files can contain 30, 100, or more data points per pixel, causing file sizes to balloon into multi-gigabyte territorymaking them unwieldy to store and analyze.When we think of digital images, we typically imagine files that store just three colors: red, green, and blue (RGB). This works well for everyday photos, but capturing the true color and behavior of light requires much more detail. Spectral images aim for this higher fidelity by recording light's intensity not just in broad RGB categories, but across dozens or even hundreds of narrow, specific wavelength bands. This detailed information primarily spans the visible spectrum and often extends into near-infrared and near-ultraviolet regions crucial for simulating how materials interact with light accurately. Figure 1 from the paper, showing relative compression ratings for a spectral image. Credit: Intel Unlike standard RGB images with their three channels, these files store information across numerous channels, each representing the intensity of light within a very specific, narrow band of wavelengths. The paper discusses working with spectral images containing 31 distinct channels and even shows examples with as many as 81 spectral bands.These channels often need to capture a much wider range of brightness values than typical photos. To handle this, spectral images frequently use high-precision formats like 16-bit or 32-bit floating-point numbers for each channel, enabling High Dynamic Range (HDR) data capture. This is a far cry from standard 8-bit images and is key for accurately representing things like the intense brightness of light sources alongside darker scene elements.Exploring a world beyond RGBWhy would anyone need this level of wavelength detail in an image? There are many reasons. Car manufacturers want to predict exactly how paint will look under different lighting. Scientists use spectral imaging to identify materials by their unique light signatures. And rendering specialists need it to accurately simulate real-world optical effects like dispersion (rainbows from prisms, for example) and fluorescence.For instance, past Ars Technica coverage has highlighted how astronomers analyzed spectral emission lines from a gamma-ray burst to identify chemicals in the explosion, how physicists reconstructed original colors in pioneering 19th century photographs, and how multispectral imaging revealed hidden, centuries-old text and annotations on medieval manuscripts like the Voynich Manuscript, sometimes even uncovering the identities of past readers or scribes through faint surface etchings. Medieval scholar Lisa Fagin Davis examined multispectral images of 10 pages from the Voynich manuscript. Credit: Lisa Fagin Davis The current standard format for storing this kind of data, OpenEXR, wasn't designed with these massive spectral requirements in mind. Even with built-in lossless compression methods like ZIP, the files remain unwieldy for practical work as these methods struggle with the large number of spectral channels.Spectral JPEG XL utilizes a technique used with human-visible images, a math trick called a discrete cosine transform (DCT), to make these massive files smaller. Instead of storing the exact light intensity at every single wavelength (which creates huge files), it transforms this information into a different form.Think of it like this: When you look at a rainbow's color transition, you don't need to record every possible wavelength to understand what you see. The DCT works by converting these smooth wavelength patterns into a set of wave-like patterns (frequency coefficients) that, when added together, re-create the original spectral information.It's similar to how MP3 works for musicrather than storing every tiny vibration in a sound wave, MP3 keeps the important frequency patterns that our ears can detect and discards the rest. Here, Spectral JPEG XL keeps the important patterns that define how light interacts with materials and compresses the less critical details.Importantly, it then applies a weighting step, dividing higher-frequency spectral coefficients by the overall brightness (the DC component), allowing less important data to be compressed more aggressively. That is then fed into the codec, and rather than inventing a completely new file type, the method uses the compression engine and features of the standardized JPEG XL image format to store the specially prepared spectral data.Making spectral images easier to work withAccording to the researchers, the massive file sizes of spectral images have reportedly been a real barrier to adoption in industries that would benefit from their accuracy. Smaller files mean faster transfer times, reduced storage costs, and the ability to work with these images more interactively without specialized hardware.The results reported by the researchers seem impressivewith their technique, spectral image files shrink by 10 to 60 times compared to standard OpenEXR lossless compression, bringing them down to sizes comparable to regular high-quality photos. They also preserve key OpenEXR features like metadata and high dynamic range support.While some information is sacrificed in the compression processmaking this a "lossy" formatthe researchers designed it to discard the least noticeable details first, focusing compression artifacts in the less important high-frequency spectral details to preserve important visual information.Of course, there are some limitations. Translating these research results into widespread practical use hinges on the continued development and refinement of the software tools that handle JPEG XL encoding and decoding. Like many cutting-edge formats, the initial software implementations may need further development to fully unlock every feature. It's a work in progress.And while Spectral JPEG XL dramatically reduces file sizes, its lossy approach may pose drawbacks for some scientific applications. Some researchers working with spectral data might readily accept the trade-off for the practical benefits of smaller files and faster processing. Others handling particularly sensitive measurements might need to seek alternative methods of storage.For now, the new technique remains primarily of interest to specialized fields like scientific visualization and high-end rendering. However, as industries from automotive design to medical imaging continue generating larger spectral datasets, compression techniques like this could help make those massive files more practical to work with.Benj EdwardsSenior AI ReporterBenj EdwardsSenior AI Reporter Benj Edwards is Ars Technica's Senior AI Reporter and founder of the site's dedicated AI beat in 2022. He's also a tech historian with almost two decades of experience. In his free time, he writes and records music, collects vintage computers, and enjoys nature. He lives in Raleigh, NC. 1 Comments

Science under attack Report: US scientists lost $3 billion in NIH grants since Trump took office Scientist warn pipeline of lifesaving discoveries and younger scientists is drying up. Beth Mole Mar 28, 2025 5:21 pm | 31 An empty research lab. Credit: Getty | Mint Images An empty research lab. Credit: Getty | Mint Images Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreSince Trump took office on January 20, research funding from the National Institutes of Health has plummeted by more than $3 billion compared with the pace of funding in 2024, according to an analysis by The Washington Post.By this time in March 2024, the NIH had awarded US researchers a total of $1.027 billion for new grants or competitive grant renewals. This year, the figure currently stands at about $400 million. Likewise, funding for renewals of existing grants without competition reached $4.5 billion by this time last year, but has only hit $2 billion this year. Together, this slowdown amounts to a 60 percent drop in grant support for a wide variety of researchfrom studies on cancer treatments, diabetes, Alzheimer's, vaccines, mental health, transgender health, and more.The NIH is the primary source of funding for biomedical research in the US. NIH grants support more than 300,000 scientists at more than 2,500 universities, medical schools, and other research organizations across all 50 states.In the near term, the missing grant money means clinical trials have been abruptly halted, scientific projects are being shelved, supplies can't be purchased, and experiments can't be run. But, in the long run, it means a delay in scientific advancements and treatment, which could echo across future generations. With funding in question, academic researchers may be unable to retain staff or train younger scientists.As Ars Technica has previously reported, graduate programs across the country have reduced or, in some cases, completely eliminated classes of incoming doctoral candidates. Some smaller academic labs fear being shut down completely.Given the funding uncertainty, Dino Di Carlo, a bioengineering professor and entrepreneur from the University of California, Los Angeles, told the Post that, for the first time in 20 years, he is not recruiting new PhD students to join his lab."I talked to our industry advisory board, and I told them, five years from now, youre going to have 50 percent less PhD students from bioengineering that you can potentially recruit to your companies," Di Carlo told the Post.A senior NIH official spoke to the paper of lost progress and cures: "Imagine if this were happening during the breast cancer research boom 30 years ago, where we were finding better ways to identify subtypes of breast cancer and targeted treatments," said the official, who spoke on the condition of anonymity. "More women would be dying now of breast cancer, left and right. Same thing with prostate cancer. You stop the pipeline, you pay with access to fewer cures later."Beth MoleSenior Health ReporterBeth MoleSenior Health Reporter Beth is Ars Technicas Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes. 31 Comments

Mike Intrator, Chief Executive Officer and founder of CoreWeave, (C) rings the opening bell surrounded by Executive Leadership and family during the company's Initial Public Offering (IPO) at the Nasdaq headquarters on March 28, 2025 in New York City. Michael M. Santiago/Getty Images 2025-03-28T21:57:43Z SaveSaved Read in app This story is available exclusively to Business Insider subscribers. Become an Insider and start reading now.Have an account? CoreWeave's Nasdaq debut saw shares fall below their IPO price, raising market concerns.CoreWeave is the first US pure-play AI public offering, relying heavily on Nvidia GPUs.The IPO tests the neocloud concept, with implications for AI's future and Nvidia's role.CoreWeave listed on the Nasdaq Friday amid a shifting narrative and much anticipation. The company priced its IPO at $40 per share. The stock flailed, opening at $39 per share, then falling as much as 6% and ending the day back up at $41.59.The cloud firm, founded in 2017, is the first pure-play AI public offering in the US. CoreWeave buys graphics processing units from Nvidia and then pairs them with software to give companies an easy way to access the GPUs and achieve the top performance of their AI products and services.The company's financial future is dependent on two unknowns that the use and usefulness of AI will grow immensely, and that those workloads will continue to run on Nvidia GPUs.It's no wonder that the listing has often been described as a bellwether for the entire AI industry.But CoreWeave's specific business has some contours that could be responsible for Friday's ambivalent debut without passing judgment on AI as a whole.CoreWeave customers are highly concentrated and its suppliers are even more so. The company is highly leveraged, with billions in debt, collateralized by GPUs. The future obsolescence of those GPUs is looming.Umesh Padval, managing director of Thomvest expects the pricing for the GPU computing CoreWeave offers to go down in the next 12 to 18 months as GPU supply continues to improve, which could challenge the company's future profitability."In general, it's not a bellwether in my opinion," Padval told Business Insider.Beyond opening daySo what does it mean that CoreWeave's debut didn't rise to meet hopes and expectations?Karl Mozurkewich, principal architect at cloud firm Valdi told BI the Friday IPO is more of a test for the neocloud concept than for AI. Neoclouds are a term used to describe young public cloud providers that solely focus on accelerated computing. They often use Nvidia's preferred reference architecture and, in theory, demonstrate the best possible performance for Nvidia's hardware.Nvidia CEO Jensen Huang gave the buch a shoutout at the company's tentpole GTC conference last week."What they do is just one thing. They host GPUs," Huang said to an audience of nearly 18,000. "They call themselves GPU clouds, and one of our great partners, CoreWeave, is in the process of going public and we're super proud of them."CoreWeave's public market performance will signal what shape the future could take for these companies, according to Mozurkewich. Will more companies try to replicate the GPU-cloud model? Will Nvidia seed more similar businesses? Will it continue to give neoclouds early access to new hardware?"I think the industry is very interested to see if the shape of CoreWeave is long-term successful," Mozurkewich said.Daniel Newman, CEO of the Futurum Group, told BI that CoreWeave is "one measuring point of the AI trade; it isn't entirely indicative of the overall AI market or AI demand." He added the company has the opportunity to improve its fate as AI scales and the customer base grows and diversifies.Lucas Keh, Semiconductors Analyst at Third Bridge agreed."Currently, more than 70% of CoreWeave's revenue comes from hyperscalers, but our experts expect this concentration to decrease 12 years after an IPO as the company diversifies its customer base beyond public cloud customers," Keh said via email.Having a handful of large, dominant enterprise customers is not uncommon for a young provider like CoreWeave, Mozurkewich said. But it's also no surprise that it could concern investors."This is where CoreWeave has a chance to shine as AI and the demand for AI spans beyond the big 7 to 10 names. The caveat will be how stable GPU prices are as availability increases and competition increases," Newman said.Other issues, like obsolescence, the necessary depreciation, and leverage will be harder to shake.Have a tip or an insight to share? Contact Emma at ecosgrove@businessinsider.com or use the secure messaging app Signal: 443-333-9088Recommended video

Samuel Corum/Getty Images 2025-03-28T21:37:22Z SaveSaved Read in app This story is available exclusively to Business Insider subscribers. Become an Insider and start reading now.Have an account? Elon Musk on Friday announced in a post on X that his artificial intelligence company, xAI, had acquired his social media platform, X, in an all-stock deal."The combination values xAI at $80 billion and X at $33 billion ($45B less $12B debt)," Musk wrote. "Since its founding two years ago, xAI has rapidly become one of the leading AI labs in the world, building models and data centers at unprecedented speed and scale. X is the digital town square where more than 600M active users go to find the real-time source of ground truth and, in the last two years, has been transformed into one of the most efficient companies in the world, positioning it to deliver scalable future growth."He added: "xAI and X's futures are intertwined. Today, we officially take the step to combine the data, models, compute, distribution and talent. This combination will unlock immense potential by blending xAI's advanced AI capability and expertise with X's massive reach. The combined company will deliver smarter, more meaningful experiences to billions of people while staying true to our core mission of seeking truth and advancing knowledge. This will allow us to build a platform that doesn't just reflect the world but actively accelerates human progress. I would like to recognize the hardcore dedication of everyone at xAI and X that has brought us to this point. This is just the beginning. Thank you for your continued partnership and support."A spokesperson for X declined to comment on the deal when reached by Business Insider.This is a developing story. Please check back for updates.Recommended video

This story appeared in The Logoff, a daily newsletter that helps you stay informed about the Trump administration without letting political news take over your life. Subscribe here.Welcome to The Logoff: Today Im focusing on the Trump administrations effort to eliminate the US Agency for International Development, the next step in its campaign against foreign assistance and a key test of whether anyone will check this administrations power grabs.Whats the latest? Secretary of State Marco Rubio this afternoon said hed notified Congress that the administration intends to fully close USAID, effective July 1. The agency is to be folded into the State Department, almost all positions are set to be eliminated, and layoffs are slated to begin almost immediately, CNN reports.Back up. Didnt they do this already? Immediately upon taking office, the administration led by Elon Musks Department of Government Efficiency began gutting USAID and froze spending on foreign assistance. Today makes it clear the administration aims to finish the job.What does todays news mean for foreign aid? Rubio said some of the agencys functions would be taken over by the State Department and the rest would be eliminated. He did not specify what would remain, but the administration has been up-front about its plan to sharply curtail foreign assistance. Thats a decision with deadly consequences for vulnerable people around the world.Does Trump have the power to do this? Congress passed a law codifying USAIDs existence, and under the traditional understanding of the US system of checks and balances only Congress has the power to shutter it. Earlier this month, a federal judge ordered a temporary freeze of some of the dismantling effort, ruling that DOGE likely violated the Constitution. Whats the big picture? Regardless of where the legal challenges end up, the administration has already done so much to gut USAID that theres little to no chance of it being reassembled. Its part of Trumps pattern of asserting new powers, making irrevocable changes with those powers, and daring anyone to stop him.And with that, its time to log off. I always feel weird delivering dark news and then imploring you to log off, but I do so because I dont think doomscrolling getting passively sucked in by social media helps anyone. It saps our energy and appetite to make positive change. And positive change is possible! To that end, I want to reshare this piece from my colleague Sigal Samuel on how we can help people affected by cuts to foreign aid. Ive shared it before, but today felt like a good day for a reprise. Thanks for reading, and Ill see you back here on Monday.See More:

For the second time in a year, Elon Musk appears to be trying to bribe voters and election law experts say its probably illegal. Musk offered Thursday to personally hand over a total of $2 million to two individuals who have already voted in the closely watched Wisconsin Supreme Court race. (Its unclear whether the payment is conditional on voting for Musks preferred candidate.)Following threats of potential legal blowback, however, he said that the recipients of the $1 million reward would instead be chosen on the basis of their ability to be effective spokespeople for a petition against activist judges. His PAC has also offered $100 to anyone who signs the petition.Musks spending has already made the Supreme Court race the most expensive in Wisconsin history. The stakes are high: The election will determine the courts ideological balance and potentially the future of abortion rights, electoral maps, and unions in the critical battleground state. Its the second time in two years that control of the court has been up for grabs. Its also the second time that Musk has promised cash rewards to voters, and last time, he didnt face any repercussions. Heres what we know.When was the last time Musk tried something like this? In 2024, Musks PAC orchestrated a $1 million daily giveaway to registered voters in battleground states. The PAC initially said the recipients would be selected randomly in a lottery that the Philadelphia district attorney argued was a violation of state election law. Election law experts also argued that it violated federal law prohibiting cash payments for registering to vote or casting a ballot, including as part of a lottery. The PAC later claimed that recipients were selected not via lottery, but based on whether they could be effective spokespeople for the PAC, which ultimately spent more than $200 million to help elect Trump. That was enough to satisfy a Pennsylvania judge, who allowed that giveaway to go ahead, but the scheme spurred further lawsuits that are still ongoing.So, are Musks payments legal? In a blog post Friday, election law expert Rick Hasen, a professor at UCLA Law, said probably not. He pointed to Wisconsin state law, which states that paying voters to turn out is a crime. There is also a federal prohibition on vote-buying, but that doesnt kick in when there are no federal candidates on the ballot, and its not clear that Trumps Department of Justice would even prosecute Musk if it could, Hasen wrote. Still, its alarming that the richest man in the world could be trying to buy votes in a highly contested and consequential election and that at least one state court has already greenlighted a similar scheme before. Wisconsin Democratic Party Chair Ben Wikler said in a statement Friday, Musk can have his day in court, but he cannot buy the court.See More: