COLOR

LIGHTING

  • What is the Light Field?

    http://lightfield-forum.com/what-is-the-lightfield/

     

    The light field consists of the total of all light rays in 3D space, flowing through every point and in every direction.

    How to Record a Light Field

     

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  • Photography basics: Solid Angle measures

    http://www.calculator.org/property.aspx?name=solid+angle

     

     

    A measure of how large the object appears to an observer looking from that point. Thus. A measure for objects in the sky. Useful to retuen the size of the sun and moon… and in perspective, how much of their contribution to lighting. Solid angle can be represented in ‘angular diameter’ as well.

    http://en.wikipedia.org/wiki/Solid_angle

     

    http://www.mathsisfun.com/geometry/steradian.html

     

    A solid angle is expressed in a dimensionless unit called a steradian (symbol: sr). By default in terms of the total celestial sphere and before atmospheric’s scattering, the Sun and the Moon subtend fractional areas of 0.000546% (Sun) and 0.000531% (Moon).

     

    http://en.wikipedia.org/wiki/Solid_angle#Sun_and_Moon

     

    On earth the sun is likely closer to 0.00011 solid angle after athmospheric scattering. The sun as perceived from earth has a diameter of 0.53 degrees. This is about 0.000064 solid angle.

    http://www.numericana.com/answer/angles.htm

     

    The mean angular diameter of the full moon is 2q = 0.52° (it varies with time around that average, by about 0.009°). This translates into a solid angle of 0.0000647 sr, which means that the whole night sky covers a solid angle roughly one hundred thousand times greater than the full moon.

     

    More info

     

    http://lcogt.net/spacebook/using-angles-describe-positions-and-apparent-sizes-objects

    http://amazing-space.stsci.edu/glossary/def.php.s=topic_astronomy

     

    Angular Size

    The apparent size of an object as seen by an observer; expressed in units of degrees (of arc), arc minutes, or arc seconds. The moon, as viewed from the Earth, has an angular diameter of one-half a degree.

     

    The angle covered by the diameter of the full moon is about 31 arcmin or 1/2°, so astronomers would say the Moon’s angular diameter is 31 arcmin, or the Moon subtends an angle of 31 arcmin.

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  • 9 Best Hacks to Make a Cinematic Video with Any Camera

    https://www.flexclip.com/learn/cinematic-video.html

    • Frame Your Shots to Create Depth
    • Create Shallow Depth of Field
    • Avoid Shaky Footage and Use Flexible Camera Movements
    • Properly Use Slow Motion
    • Use Cinematic Lighting Techniques
    • Apply Color Grading
    • Use Cinematic Music and SFX
    • Add Cinematic Fonts and Text Effects
    • Create the Cinematic Bar at the Top and the Bottom

     

     

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  • domeble – Hi-Resolution CGI Backplates and 360° HDRI

    www.domeble.com/

    When collecting hdri make sure the data supports basic metadata, such as:

    • Iso
    • Aperture
    • Exposure time or shutter time
    • Color temperature
    • Color space Exposure value (what the sensor receives of the sun intensity in lux)
    • 7+ brackets (with 5 or 6 being the perceived balanced exposure)

     

    In image processing, computer graphics, and photography, high dynamic range imaging (HDRI or just HDR) is a set of techniques that allow a greater dynamic range of luminances (a Photometry measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle) between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. This wider dynamic range allows HDR images to represent more accurately the wide range of intensity levels found in real scenes ranging from direct sunlight to faint starlight and to the deepest shadows.

     

    The two main sources of HDR imagery are computer renderings and merging of multiple photographs, which in turn are known as low dynamic range (LDR) or standard dynamic range (SDR) images. Tone Mapping (Look-up) techniques, which reduce overall contrast to facilitate display of HDR images on devices with lower dynamic range, can be applied to produce images with preserved or exaggerated local contrast for artistic effect. Photography

     

    In photography, dynamic range is measured in Exposure Values (in photography, exposure value denotes all combinations of camera shutter speed and relative aperture that give the same exposure. The concept was developed in Germany in the 1950s) differences or stops, between the brightest and darkest parts of the image that show detail. An increase of one EV or one stop is a doubling of the amount of light.

     

    The human response to brightness is well approximated by a Steven’s power law, which over a reasonable range is close to logarithmic, as described by the Weber�Fechner law, which is one reason that logarithmic measures of light intensity are often used as well.

     

    HDR is short for High Dynamic Range. It’s a term used to describe an image which contains a greater exposure range than the “black” to “white” that 8 or 16-bit integer formats (JPEG, TIFF, PNG) can describe. Whereas these Low Dynamic Range images (LDR) can hold perhaps 8 to 10 f-stops of image information, HDR images can describe beyond 30 stops and stored in 32 bit images.

     

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  • Ethan Roffler interviews CG Supervisor Daniele Tosti

    Ethan Roffler
    I recently had the honor of interviewing this VFX genius and gained great insight into what it takes to work in the entertainment industry. Keep in mind, these questions are coming from an artist’s perspective but can be applied to any creative individual looking for some wisdom from a professional. So grab a drink, sit back, and enjoy this fun and insightful conversation.



    Ethan

    To start, I just wanted to say thank you so much for taking the time for this interview!

    Daniele
    My pleasure.
    When I started my career I struggled to find help. Even people in the industry at the time were not that helpful. Because of that, I decided very early on that I was going to do exactly the opposite. I spend most of my weekends talking or helping students. ;)

    Ethan
    That’s awesome! I have also come across the same struggle! Just a heads up, this will probably be the most informal interview you’ll ever have haha! Okay, so let’s start with a small introduction!

    Daniele
    Short introduction: I worked very hard and got lucky enough to work on great shows with great people. ;) Slightly longer version: I started working for a TV channel, very early, while I was learning about CG. Slowly made my way across the world, working along very great people and amazing shows. I learned that to be successful in this business, you have to really love what you do as much as respecting the people around you. What you do will improve to the final product; the way you work with people will make a difference in your life.

    Ethan
    How long have you been an artist?

    Daniele
    Loaded question. I believe I am still trying and craving to be one. After each production I finish I realize how much I still do not know. And how many things I would like to try. I guess in my CG Sup and generalist world, being an artist is about learning as much about the latest technologies and production cycles as I can, then putting that in practice. Having said that, I do consider myself a cinematographer first, as I have been doing that for about 25 years now.

    Ethan
    Words of true wisdom, the more I know the less I know:) How did you get your start in the industry?
    How did you break into such a competitive field?

    Daniele
    There were not many schools when I started. It was all about a few magazines, some books, and pushing software around trying to learn how to make pretty images. Opportunities opened because of that knowledge! The true break was learning to work hard to achieve a Suspension of Disbelief in my work that people would recognize as such. It’s not something everyone can do, but I was fortunate to not be scared of working hard, being a quick learner and having very good supervisors and colleagues to learn from.

    Ethan
    Which do you think is better, having a solid art degree or a strong portfolio?

    Daniele
    Very good question. A strong portfolio will get you a job now. A solid strong degree will likely get you a job for a longer period. Let me digress here; Working as an artist is not about being an artist, it’s about making money as an artist. Most people fail to make that difference and have either a poor career or lack the understanding to make a stable one. One should never mix art with working as an artist. You can do both only if you understand business and are fair to yourself.



    Ethan

    That’s probably the most helpful answer to that question I have ever heard.
    What’s some advice you can offer to someone just starting out who wants to break into the industry?

    Daniele
    Breaking in the industry is not just about knowing your art. It’s about knowing good business practices. Prepare a good demo reel based on the skill you are applying for; research all the places where you want to apply and why; send as many reels around; follow up each reel with a phone call. Business is all about right time, right place.

    Ethan
    A follow-up question to that is: Would you consider it a bad practice to send your demo reels out in mass quantity rather than focusing on a handful of companies to research and apply for?

    Daniele
    Depends how desperate you are… I would say research is a must. To improve your options, you need to know which company is working on what and what skills they are after. If you were selling vacuum cleaners you probably would not want to waste energy contacting shoemakers or cattle farmers.

    Ethan
    What do you think the biggest killer of creativity and productivity is for you?

    Daniele
    Money…If you were thinking as an artist. ;) If you were thinking about making money as an artist… then I would say “thinking that you work alone”.

    Ethan
    Best. Answer. Ever.
    What are ways you fight complacency and maintain fresh ideas, outlooks, and perspectives

    Daniele
    Two things: Challenge yourself to go outside your comfort zone. And think outside of the box.

    Ethan
    What are the ways/habits you have that challenge yourself to get out of your comfort zone and think outside the box?

    Daniele
    If you think you are a good character painter, pick up a camera and go take pictures of amazing landscapes. If you think you are good only at painting or sketching, learn how to code in python. If you cannot solve a problem, that being a project or a person, learn to ask for help or learn about looking at the problem from various perspectives. If you are introvert, learn to be extrovert. And vice versa. And so on…

    Ethan
    How do you avoid burnout?

    Daniele
    Oh… I wish I learned about this earlier. I think anyone that has a passion in something is at risk of burning out. Artists, more than many, because we see the world differently and our passion goes deep. You avoid burnouts by thinking that you are in a long term plan and that you have an obligation to pay or repay your talent by supporting and cherishing yourself and your family, not your paycheck. You do this by treating your art as a business and using business skills when dealing with your career and using artistic skills only when you are dealing with a project itself.

    Ethan
    Looking back, what was a big defining moment for you?

    Daniele
    Recognizing that people around you, those being colleagues, friends or family, come first.
    It changed my career overnight.

    Ethan
    Who are some of your personal heroes?

    Daniele
    Too many to list. Most recently… James Cameron; Joe Letteri; Lawrence Krauss; Richard Dawkins. Because they all mix science, art, and poetry in their own way.

    Ethan
    Last question:
    What’s your dream job? ;)

    Daniele
    Teaching artists to be better at being business people… as it will help us all improve our lives and the careers we took…

    Being a VFX artist is fundamentally based on mistrust.
    This because schedules, pipelines, technology, creative calls… all have a native and naive instability to them that causes everyone to grow a genuine but beneficial lack of trust in the status quo. This is a fine balance act to build into your character. The VFX motto: “Love everyone but trust no one” is born on that.

     

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  • About green screens

    hackaday.com/2015/02/07/how-green-screen-worked-before-computers/

     

    www.newtek.com/blog/tips/best-green-screen-materials/

     

    www.chromawall.com/blog//chroma-key-green

     

     

    Chroma Key Green, the color of green screens is also known as Chroma Green and is valued at approximately 354C in the Pantone color matching system (PMS).

     

    Chroma Green can be broken down in many different ways. Here is green screen green as other values useful for both physical and digital production:

     

    Green Screen as RGB Color Value: 0, 177, 64
    Green Screen as CMYK Color Value: 81, 0, 92, 0
    Green Screen as Hex Color Value: #00b140
    Green Screen as Websafe Color Value: #009933

     

    Chroma Key Green is reasonably close to an 18% gray reflectance.

     

    Illuminate your green screen with an uniform source with less than 2/3 EV variation.
    The level of brightness at any given f-stop should be equivalent to a 90% white card under the same lighting.

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  • Debayer – A free command line tool to convert camera raw images into scene-linear exr

    https://github.com/jedypod/debayer

     

     

    The only required dependency is oiiotool. However other “debayer engines” are also supported.

    • OpenImageIO – oiiotool is used for converting debayered tif images to exr.
    • Debayer Engines
      • RawTherapee – Powerful raw development software used to decode raw images. High quality, good selection of debayer algorithms, and more advanced raw processing like chromatic aberration removal.
      • LibRaw – dcraw_emu commandline utility included with LibRaw. Optional alternative for debayer. Simple, fast and effective.
      • Darktable – Uses darktable-cli plus an xmp config to process.
      • vkdt – uses vkdt-cli to debayer. Pretty experimental still. Uses Vulkan for image processing. Stupidly fast. Pretty limited.
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  • Christopher Butler – Understanding the Eye-Mind Connection – Vision is a mental process

    https://www.chrbutler.com/understanding-the-eye-mind-connection

     

    The intricate relationship between the eyes and the brain, often termed the eye-mind connection, reveals that vision is predominantly a cognitive process. This understanding has profound implications for fields such as design, where capturing and maintaining attention is paramount. This essay delves into the nuances of visual perception, the brain’s role in interpreting visual data, and how this knowledge can be applied to effective design strategies.

     

    This cognitive aspect of vision is evident in phenomena such as optical illusions, where the brain interprets visual information in a way that contradicts physical reality. These illusions underscore that what we “see” is not merely a direct recording of the external world but a constructed experience shaped by cognitive processes.

     

    Understanding the cognitive nature of vision is crucial for effective design. Designers must consider how the brain processes visual information to create compelling and engaging visuals. This involves several key principles:

    1. Attention and Engagement
    2. Visual Hierarchy
    3. Cognitive Load Management
    4. Context and Meaning

     

     

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