Glossary
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Rendering intent, generally used for proofing. Based on a device-independent color space, reproducing colors within the available gamut perfectly, and reducing colors outside of the gamut to the nearest reproducible hue (at the expense of saturation).
Aliasing
Jagged edges caused by pixels. Occurs most often in low resolution images or images that have been enlarged. See jaggies.
Anchor
Method of fixing an object such as a selection to a screen, page, or image location.
Antialiasing, Anti-Aliasing
Software technique for reducing jagged lines, or ‘jaggies’. Uses shades of gray and color to smooth out the contrast between adjacent pixels.
An image’s width-to-height ratio. For example, an image with an aspect ratio of 3:1 has a width 3 times larger than its height.
Azimuth
Angle of shadows that extend from the edges of image details. In Gemstone you can control azimuth when applying the Emboss effect to an image.
Background Processing
Tasks or programs that function without user interaction.
Bandwidth
Amount of data that can be sent through a network connection in a fixed amount of time. Bandwidth is measured in kilobits per second (Kbps).
Barrel Distortion
In barrel distortion the photo appears to bulge outwards from the center.
Bit
Bits are small units of computer memory. The color depth of your image is constrained by the number of bits available to store color information. For example, it is possible to store 256 different color values per color channel in 8-bit RGB images. Similarly, it is possible to store 65,536 different color values per color channel in 18-bit images.
Blackpoint
An image’s darkest area. You can control the intensity of the black in an image by adjusting its blackpoint.
Blend Modes
Filters that change the effect of a tool or the appearance of a selected object.
Brightness
Light intensity of an image. You can make an image appear brighter or darker by adjusting its brightness.
Brush
A tool that you can use to isolate or indicate pixels you want to apply effects or adjustments to. The Brush in Drawing Tools can be used to draw in color on your image. See Smart Brushing.
Chromatic Aberration
A lens artifact that can result in fringes in high contrast areas of some photos.
CMYK
Color model that uses cyan, magenta, yellow, and black (key) as its primary colors.
Color Cast
Changes the hue of an image while keeping the saturation and brightness intact. For example, many digital cameras produce pictures with a slightly blue color cast. Gemstone includes a tool that removes an unwanted color cast.
Color Channel Value
Contains all pixel information for a single color. A grayscale image has one channel, while an RGB image has three channels. You can adjust RGB values when editing a color.
Color Gamut
Range of colors that a device such as a printer or monitor can produce or display.
Color Management
Process of adjusting your computer settings so that the color output from your printer matches the colors you see on your monitor.
Color Space
There are two types of color spaces: device-independent or device-dependent. A device-independent color space, such as RGB, describes all possible colors. A device-dependent color space describes the subset of colors (from the device-independent color space) that a particular device can reproduce. Device-dependent color spaces are used to map colors between devices (for example, from a monitor to a printer) to ensure that colors are reproduced accurately.
Compression
Process that converts data to a storage format requiring less space than the original data.
Physical or digital page that contains a series of small images, usually in a grid format.
Contrast
Measure of an image’s color and brightness differences.
Convert
Change a file from one format to another. For example, you might convert a file from a bitmap (.bmp) to a JPEG (.jpg) to reduce the file size.
Cropping
Removing unwanted image areas.
Dock
Attaching a toolbar, window, or pane to different screen areas.
DPI (dots per inch)
Measurement of an image’s resolution. For example, 92 DPI means 92 dots horizontally and 92 dots vertically, which equals 8,464 dots per square inch. More dots per inch result in higher resolution and image quality.
Dynamic Range
The dynamic range of an image is directly related to the dynamic range of your digital camera's sensor. If your digital camera's sensor has a large dynamic range it can capture the darkest shadows and brightest highlights at the same time, without clipping the shadows or highlights. (RAW images preserve the dynamic range of your digital camera's sensor.) Adjusting the tonal range of the image changes how the dynamic range of the image is represented on a monitor or in a photo.
Elevation
Height of an imaginary light source over an image. The elevation of the light source works in conjunction with azimuth to generate a three-dimensional emboss effect.
Encode
Writing (or saving) a file format.
Encryption
Method of converting data into a secure format. You need a digital password or key to read an encrypted file.
EXIF (Exchangeable Image File)
Standard for storing information, primarily with images that use JPEG compression. Most digital cameras create EXIF information and embed it in the image file. For example, EXIF information can include details about shutter speed and whether a flash was used.
Export
Moving data from one application to another. The exporting application places the data in a format that the other application understands.
Exposure
Exposure is the amount of time that your digital camera's sensor is exposed to light.
Feather
Softening image edges to blend them into the background.
File Format
Medium for encoding information in a file. Each type of file has a different file format that specifies how it organizes the information it contains.
Filter
Program that can apply an effect to an image, such as an embossed appearance or a sepia tone.
Fisheye Distortion
In fisheye distortion, the photo appears to bulge outwards from the center, as if the photo were wrapped around a sphere.
Gamma
Range of color values a monitor, scanner, or printer can display. Adjusting this value increases or decreases the intensity of the light spectrum.
Grayscale Image
Image composed of different shades of gray.
Highlights
Highlights are the brightest or whitest parts of an image.
Histogram
A histogram is a graph that displays the dynamic range of shadows and highlights in an image.
HSL
An acronym for hue, saturation, and lightness.
Hue
Predominant color in an image.
Image Resolution
Quality of image details and colors. Also used to describe the quality of monitors and printer output.
Process that uses nearby pixels to estimate the color of new pixels added to the larger image. For example, interpolation might be used when enlarging a digital image.
Individual pixels displayed in an image with low resolution. The appearance of pixels in an image causes lines and curves to appear jagged.
Lens Vignetting
Unusual darkness in the corners of images as a result of an inability of the lens to distribute light into the corners of the image.
Lossless Compression
Form of compression that retains all image data and quality.
Lossless Rotation and Flipping
Rotation of a JPEG image without loss of image quality. This works best on images with dimensions that are a multiple of 8 or 16.
Lossy Compression
Form of compression that attempts to remove unnecessary data. This data loss can affect image quality.
Dashed-line frame that identifies a selected portion of an image. Depending on the tool, you can resize or move a marquee with or without changing the underlying image.
Information about an image and how it was taken. For example, the metadata of digital camera images can contain the date and time the picture was taken, the shutter speed, the exposure settings of the camera, and whether a flash was used.
Monochrome Image
Image containing a single color.
Noise
Effect produced when a variety of pixel colors are used in the same color region. Noise often occurs in images with high ISO setting or slow shutter speed.
Opacity
Determines how visible an effect is when applied to an image or a selection. High opacity produces a more solid effect, while low opacity results in a nearly invisible effect.
Overexposed
Images that are overexposed have too many highlights, and tend to look faded. You typically overexpose images by exposing your digital camera's sensor to light for too long.
Panning
Moving zoomed images vertically, horizontally, and diagonally across the display area to view specific areas of the image.
Rendering intent that scales all of the colors within one gamut to fit within another gamut. Best used for photographic images, as it maintains the relationship between the colors more accurately than the colors themselves.
Perspective Distortion
Perspective distortion is caused by wide angle and telephoto lenses, which distort the perspective of large or far-away objects. For example, if you take a photo of a tall building, the building may appear to be narrower at the top even though the building is the same width from top to bottom.
Pincushion Distortion
In pincushion distortion the photo appears to shrink inwards toward the center.
Pixel (PICture ELement)
Smallest visible portion of a digital image, arranged in rows and columns.
Software module that adds functionality to a larger program.
PPI (pixels per inch)
Measurement of how an image is displayed. More pixels per inch result in higher image quality.
Presets
A preset contains image correction settings. You can create and use presets to ensure that settings you apply are the same and consistent across all images.
Primary Colors
Colors that can produce other colors when blended. For example, in the RGB color model, red, green, and blue are primary colors.
Raster Image
Image composed of a rectangular grid of pixels. Each pixel contains a defined value about its color, size, and location in the image. As a result, resizing the image can affect its quality.
RAW
An image file format. RAW files contain all of the image data that was captured by your digital camera's sensor. RAW files are not processed by your camera.
Red Eye
Red eye occurs when the light from your digital camera's flash reflects off the retinas in the subject's eyes. The subject's eyes look red instead of their normal color.
Rendering intent that maps the colors that fall exactly within the color gamuts of both the input and output devices. Best used for single- or limited-color images as colors outside of both gamuts may be mapped to a single color.
Render
Drawing images to your screen.
Rendering Intent
Approach used to map colors from one color gamut to another. There are four rendering intents available: Perceptual, Relative Colorimetric, Saturation, and Absolute Colorimetric.
Resolution
Quality and clarity of an image, measured in pixels, dots per inch, or pixels per inch.
RGB
Color model that uses red, green, and blue as its primary colors.
Distortion around the edges of image subjects, caused by compressing or resizing an image.
Saturation
Purity of a color. Higher color saturation results in more gray.
Rendering intent that maintains color saturation from one gamut to another. Best suited for images in which the actual color represented is less important than the color’s vividness.
Selection
Portion of an image that you define with a selection tool. A marquee surrounds a selection.
Sepia
Sepia-toned images are composed of shades of brown. Many old photographs have a sepia tone.
Sharpen
The sharpen tool is for sharpening images. The original image is blurred slightly. This blurred version of the image is subtracted from the original image, revealing the edges in the original image. These edges can then be sharpened by increasing contrast.
Sharpness
The sharpness in an image is determined, primarily, by your digital camera's lens and sensor. You can also create the illusion of sharpness by increasing the contrast between edges within an image.
Shortcut Menu
Menu that appears when you right-click within a program. Sometimes referred to as a context menu.
Brushing targeted to specific colors, brightness values, or combination of color and brightness. The Smart Brush only affects pixels similar in value to the pixel in the center of the brush stroke, and allows you to apply adjustments to those pixels.
Soft Proofing
Using your computer's monitor as a proofing device. The monitor displays a simulation of how colors will appear when rendered by the printer.
Thumbnails
Small preview of a full-sized image.
Underexposed
Images that are underexposed have too many shadows. Images typically become underexposed if you don't expose your digital camera's sensor to light long enough.
Vector Image
Image consisting of individual objects rather than pixels. Mathematical equations define the objects. You can adjust the size of a vector image and the image will retain its clarity and quality.
Watermark
Background text or graphics added to an image, usually to provide copyright protection.
White Balance
Removes color cast to create a photo that is correctly lit. You can use your camera settings to apply the correct white balance before taking an image, or correct the white balance in Gemstone.
Whitepoint
Lightest image area. You can control the intensity of the white in an image by adjusting its whitepoint.
Zoom
In Gemstone, zoom refers to the process of increasing or decreasing the display scale for an image. Increase the display scale to view a portion of an image or a specific image detail. Decrease the display scale to view more or all of the image.