What is a digital image?
PIXEL: or pixel element. These are literally are the builting blocks for an image.
Digital files are made up of string of 0 or 1 = bits
1 bit image is either 0 or 1, 2 possible shades of gray tones
An 8 bit image is a string of 8, 0s or 1s (01011010) with 256 possiblities
Bit depth tells you how smooth the tones will be. High-bit files have more data - let you make more adjustments without quality loss. Your camera images are 16bit
Every digital image has a COLOR MODE: black and white are typically grayscale while color images are typically RGB (more specifics later)
RGB Images have 3, 8 bit color channels.so they are 24bit / 16.7 million possible colors
Red greyscale, Green Greyscale and Blue grey scale. No such thing color , all color is constructed on your output device
II. FILE SIZE
file size is measured in bytes (8 bits)
Bit: smallest unit of digital information can only be a value between 0 and 1
Byte: 8 bits can be 256 values
kilobyte (1kb) 1,000 bytes
Megabyte (1mb) 100,000 kilobytes
Gigabyte (1GB) 1,000,000 kilobytes
Terabyte (1TB) 1,000,000 megabytes or 1,000 Gigabytes
Pixel dimensions measure the total number of pixels along an image’s width and height. Because we are creating images to be PRINTED it is important to pay attention to not only pixel dimension but also linear resolution or print dimension/document size- the higher the resolution the better the print quality. We will print on our letter sized paper at 300dpi (dots per inch) also sometimes refered to as ppi (pixels per inch)
III. File Formats
raw files(.cr2, .nef, .arw, etc): Camera raw files preserve all captured data. If you are downloading jpgs from your cmaera you are accepting the cameras interpretation of what the sensor captured rather than the original data. unprocessed data.
.dng (digital negative) open source format developed by Adobe that standardize raw format. (may PRINT)
.psd is adobe’s proprietary format for photoshop documents. Usually used if you are working in photoshop and wish to save layers.
.tif is a universal format that is lossless (for PRINT)
.jpg: compresses photographs into smaller file. it is a lossy compression - deteriorates everytime you save the file. FOR DISPLAY
III. COLOR
RGB color is addative
Adding equal parts of the primary colors together creates white - the absence of color is black. Examples include the screen you are reading this one, projectors, TV, etc.
CMYK is Subtractive color
Created when white light is reflected off a pigmented or dyed surface. Rather then adding wavelengths to black, they act to subtract or absorb wavelengths from an otherwise white source of light.
COLOR SPACE ADOBE RGB 1998 VS sRGB
RGB color space is most similar model to human vision. Adobe RGB 1998 colors space encompaces 50% of what is visible to the human eye.