Blending Modes in Graphic Design

Image File Formats

• GIF:
  • 8-bit-per-pixel bitmap image format
  • Supports animations and allows a separate palette of 256 colors for each frame
  • Compressed using Lempel-Ziv-Welch (LZW) lossless data compression technique
  • Unsuitable for reproducing color photographs and other images with continuous color
• JPEG:
  • Joint Photographic Experts Group (JPEG) format
  • Specifies both the codec and file format used to contain the stream of bytes
  • Allows for adjustable compression, trading off storage size and image quality
  • Typically achieves 10:1 compression with little perceivable loss in image quality
• TIFF:
  • Tagged Image File Format (TIFF) for images, including photographs and line art
  • Widely supported by image-manipulation and publishing applications
  • Has not had a major update since 1992, despite several published technical notes with minor extensions
• RAW:
  • Unprocessed data from the image sensor of a digital camera or image scanner
  • Contains the maximum amount of information the sensor is capable of collecting and saving
  • Not directly usable, requires processing by a raw converter or Adobe Photoshop
• BMP:
  • Bitmap file format used to store bitmap digital images
  • Supports 1, 4, 8, 16, 24, or 32 bits per pixel
  • May store an alpha channel (for transparency) in a separate file or as a fourth channel
• LAB:
  • Lab color space designed to approximate human vision
  • Coordinates are L for lightness and a and b for color-opponent dimensions
  • Unlike RGB and CMYK, LAB requires more data per pixel to obtain the same precision
• PNG:
  • Portable Network Graphic, a lossless, portable, and well-compressed storage format for raster images
  • Supports indexed-colors, grey scales, and truecolor images, with optional alpha channel
  • Designed for on-line viewing applications, such as the World Wide Web
• EPS:
  • Encapsulated PostScript, a DSC-conforming PostScript document with additional restrictions
  • Intended for use as a graphics file format, allowing applications to use the information to lay out the page
• Binary File:
  • Computer file containing any type of data, encoded in binary form for storage and processing
  • Can be translated into a plain text representation using, for example, Base64, which increases file size by approximately 30%

Color and Composition

• Rule of Thirds:
  • Place the main subject of an image at one of the intersections of imaginary lines, one-third from the top or bottom and one-third from the left or right side
• Bit Color:
  • 1-bit color: monochrome, often black and white
  • 2-bit color: 4 colors, used by CGA and early NeXTstation
  • 3-bit color: 8 colors, used by many early home computers
  • 4-bit color: 16 colors, used by EGA and VGA
  • 5-bit color: 32 colors, used by Original Amiga chipset
  • 6-bit color: 64 colors, used by Original Amiga chipset
  • 8-bit color: 256 colors, used by most early color Unix workstations and VGA
  • 12-bit color: 4096 colors, used by some Silicon Graphics systems and Amiga systems in HAM mode
  • HighColor or HiColor: 15 or 16 bits, providing life-like colors and supporting 32,768 mixed colors

Copyrights and Photography

• Copyright Act 1976:
  • Primary basis of copyright law in the United States
  • Spells out basic rights of copyright holders and codifies the doctrine of "fair use"
• General Information:
  • Copyright protects original works of authorship fixed in a tangible form of expression
  • Includes literary works, musical works, dramatic works, pantomimes and choreographic works, pictorial, graphic, and sculptural works, motion pictures and other audiovisual works, sound recordings, and architectural works
  • Copyright remains in effect for 70 years beyond the death of the holder
• Social Media:
  • When uploading an image or file, you're giving royalty-free and unlimited usage to the social media company
  • You retain copyright, but grant permission for the company to use your work without monetary reward
• Copyright Fees:
  • Online registration fee: $35
  • Paper registration fee: $45
  • Statutory damages for copyright infringement: up to $150,000### Color and Display
• 16-bit color, also known as "thousands of colors", uses 5 bits for red, 5 bits for green, and 5 bits for blue, resulting in 32,768 possible colors.
• 24-bit true color uses 8 bits for each of the three primary colors (red, green, and blue), resulting in 16,777,216 possible colors.
• 30-bit color uses 10 bits for each of the three primary colors, resulting in 1,073,741,824 possible colors.

Digital Imaging

• The red-eye effect in photography occurs when a photographic flash is used too close to the camera lens, causing the light to reflect off the back of the eyeball and out through the pupil.
• The red-eye effect is not seen in nature, but rather is a photographic effect.
• The color of the fundus, which is due to melanin, is the main cause of the red-eye effect.

Software

• Adobe Illustrator is a vector-based drawing program that allows users to create and edit vector graphics.
• Adobe Illustrator CS was the first version to include 3-dimensional capabilities.
• Illustrator CS includes features such as Live Trace, Live Paint, and a control palette.

File Formats

• PDF (Portable Document Format) is a file format used for document exchange, created by Adobe Systems in 1993.
• PDF is an open standard, and it is used to represent two-dimensional documents in a manner independent of the application software, hardware, and operating system.
• PDF files encapsulate a complete description of a 2-D document, including text, fonts, images, and 2-D vector graphics.

Acronyms

• ADDA: American Digital Design Association / American Design Drafting Association
• SLR: Single Lens Reflex Camera
• DSLR: Digital Single Lens Reflex Camera
• ISO: International Standards Organization (used to describe a camera's sensitivity to light)
• RAW: Raw image format, which contains minimally processed data from the image sensor of a digital camera or image scanner.
• PNG: Portable Network Graphics (a bitmapped image format that employs lossless data compression)
• GIF: Graphics Interchange Format (an 8-bit-per-pixel bitmap image format)
• PPI: Pixels per inch (a measurement of the resolution of a computer display or image size produced by a digital camera)
• LAB: The coordinates of the Hunter 1948 L, a, b color space
• ACE: A proprietary data compression archive file format
• AWB: Average White Balance (Auto White Balance)
• EXIF: Exchangeable image file format (information that accompanies an image)
• AP: Aperture Priority
• AE/AF: Auto-Exposure / Auto Focus

Cameras

• Digital cameras come in a range of shapes, sizes, and price points, with differences in image quality, features, and interchangeable lenses.
• Point and Shoot cameras are limited to automatic functionality, with a simple user interface and plastic or glass lenses.
• Digital SLR cameras have through-the-lens viewing, interchangeable lenses, and better construction.
• Cell phone and tablet cameras are a type of point and shoot camera, with limitations in image quality and features.

Definitions

• Daylight / sunlight: the combination of direct and indirect sunlight outdoors during the daytime
• Tungsten: a type of lighting that emits more warm (red, yellow) light
• Fluorescent: a type of lighting that has a distinct color spectrum and color spikes
• Color temperature: a characteristic of visible light that is determined by comparing its chromaticity with a theoretical, heated black-body radiator
• Kelvin (K): a unit of temperature, with the Kelvin scale being an absolute thermodynamic temperature scale
• F-stop: the diameter of the entrance pupil in terms of the effective focal length of the lens, a measure of lens speed
• Sensor: the digital recording chip in the camera, technically known as a CCD (charge coupled device)
• Macro lens: a type of lens that is optimized for close-up photography, with the image on the film or sensor being close to the same size as the object being photographed
• Histogram: a graphical display of tabulated frequencies, showing the distribution of tones in an image
• Overexposed: an image that appears too bright, with lost highlights and colors
• Underexposed: an image that appears too dark, with lost details in the shadows### Image Quality and Resolution
• Underexposure occurs when insufficient light is delivered to the imaging system, resulting in a dark picture.
• Pixels are the individual imaging elements of a CCD or CMOS sensor, or the individual output points of a display device.
• Resolution is measured by the number of pixels, with higher numbers indicating better quality (e.g., 640x480, 800x600, 1024x768).

Lighting

• Soft light tends to "wrap" around objects, casting shadows with soft edges.
• Factors affecting soft light include distance, size of light source, and angle between the illuminated object and light source.
• Hard light sources cast shadows with crisp edges, and can be focused to produce harder-edged shadows.
• Louvers are a source of reflecting light from a light box or other light source.
• Reflectors are used to redirect light towards a subject or scene.
• Soft boxes are a type of photographic lighting device that create soft diffused light.

Image Editing

• Curves are a remapping of image tonality, used to emphasize colors or other elements in a picture.
• Bit depth refers to the color or grey scale of each individual pixel, with higher bit depths allowing for more colors (e.g., 24-bit image with 16.7 million colors).

RAW Images

• RAW image files contain minimally processed data from the image sensor, requiring processing before use.
• RAW files are similar to film negatives, with all the information needed to create an image.
• The process of converting a RAW image file into a viewable format is called developing a RAW image.

Color and Balance

• Resolution is the quality of a digital image, depending on the number of pixels used to create the image.
• Color balance is the accuracy with which the colors captured in an image match the original scene.
• White balance is a menu option that helps with color balance.
• Primary colors are sets of colors that can be combined to make a useful range of colors (e.g., red, green, and blue).
• Secondary colors are made by mixing two primary colors (e.g., red + green = yellow).
• Tertiary colors are made by mixing one primary color with one secondary color (e.g., red + yellow = orange).

Other Terms

• Interlaced is a technique for improving picture quality on CRT devices, but can cause problems on other display devices.
• Exposure is the total amount of light allowed to fall on the photographic medium during the process of taking a photograph.
• Vector graphics are used to represent images in computer graphics, using geometrical primitives such as points, lines, and curves.
• Raster graphics are a data structure representing a rectangular grid of pixels, used to display images on a screen or print.
• Lens hood is a device used to block light and prevent glare and lens flare.
• Blooming is a computer graphics effect used to reproduce an imaging artifact of real-world cameras, producing fringes of light around very bright objects.

Concentric and Diaphragm

• Concentric objects share the same center, axis, or origin, with one inside the other.
• Diaphragm is a thin opaque structure with an opening (aperture) at its center, used to limit the brightness of light reaching the focal plane.

Fisheye Lens and EXIF

• Fisheye lens is an extreme wide-angle lens that gives a curved or spherical appearance to a photograph.
• EXIF is a specification for the image file format used by digital cameras, which includes metadata tags such as date and time, camera settings, and a thumbnail for previewing.

Composition

• Rule of thirds: place the main subject of the image in one of the intersections of imaginary lines, one-third from the top or bottom, and one-third from the left or right side.

Histograms

• Histograms show the values of all the pixels in an image, with the height of each bar representing the number of pixels on a particular brightness level.
• In an 8-bit file, the graph shows each of the 256 tones available for the photograph, with black being 0, middle gray being 128, and white being 255.