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Glossary Menu Figure Types Image Editing Terms File Formats Color Terminology Back to Figure Guidelines Guidelines to Authors (main)

Half-tone

Any figure containing continuous tone images that has no labeling or line-art on a white background or outside the image panels. These can also be called continuous-tone figures. Half-tone figures in JHC commonly contain micrographs. The following examples are typical of half-tones:

Example of a grayscale, half-tone figure panel.

Example of color, half-tone figure panels.


Note that there is no lettering or labeling is outside the panels of these figures. For a figure to be a half-tone figure, all of its panels must be half-tone images.

Line-art

Any figure that is purely made up of line drawings, and contains no half-tone or continuous-tone images. Examples include graphs, schematic drawings, and charts. The following examples are typical of line-art:

Example of a grayscale, line-art graph.

Example of a color, line-art figure panel.


Note that there are no continuous tone images in these figures. For a figure to be a line-art figure, all of its panels must be line-art.

Combination Figures (also known as Combos)

Any figure that contains both line-art and half-tone (continuous tone) images. The following examples are typical of combination figures:

Example of a grayscale combination figure.

Example of a color combination figure.


Note that there is lettering or labeling outside the panels of these figures. For a figure to be a combination figure, it must contain both line-art and half-tone images.

Flattening (also flatten)

The process of combining all the layers of an image file into a single layer. Any unseen portions of a given layer will be lost.

Layers (also layering)

A concept used by many current photo-editing programs in which parts of an image are separated into 'layers'. A layer is similar to a piece of transparency or clear plastic that is set on top of a photograph. The photograph is one layer, and the transparency is another. This enables a presenter, author, or artist to write or draw on the transparency and see their writing on the photograph without actually altering the photograph. Photo-editing programs have a wide variety of options for making use of layers in labeling, adjusting, and designing images.

Scaleable (also Scalability)

The ability to undergo an increase in resolution and/or overall print-size without reducing quality. Unrasterized images such as Vector Graphics are scaleable, but rasterized images such as half-tones are not.

Rasterize (also Rasterization, Rasterizing)

The process of taking an unrasterized image format such as a vector graphic and applying a size and resolution to it. When an image has been rasterized, it is no longer scaleable.

Rasterized Format (also Raster Format)

Images in rasterized format are composed of a series of pixels, or dots. A rasterized image's quality is determined by its resolution at the time it is generated. Changes to the resolution and size of a rasterized image after it has been made can result in a lower quality image.

Resolution

The number of pixels (or dots) over a unit of measure. The higher the resolution, the more pixels or dots in a given space, and the higher the quality. Resolution is typically measured in dots per inch (DPI), which may also be called pixels per inch.

Vector Graphic

A type of image format where the image file contains no fixed resolution and size, and is drawn as a series of vectors and lines. This can make the image easier and quicker to edit than a rasterized format, and give better results in print and online display. Vector Graphics are said to be scaleable. Line-art and combination figures reproduce in print and online the best when they are created in a Vector Graphic File Format.

Layered File Formats

A type of image format where the image file can be made up of multiple image layers. These file formats include (but are not limited to) most Vector Graphics file formats, Photoshop CS TIFF (Tagged Image File Format), PSD (Adobe Photoshop proprietary file format), and PSP (Jasc Paint Shop Pro proprietary file format). Although the Vector Graphics files of these type are scaleable, the rest are generally not.

Rasterized File Formats

File formats in which the image has a resolution and size that was set when the image was made, so that the image is rasterized. These file formats include (but are not limited to) TIFF (Tagged Image File Format), JPG (Joint Photographic Experts Group Format), GIF (Compuserve Graphics Image Format), PNG (Portable Network Graphics Format), PSD (Adobe Photoshop proprietary file format), Photoshop EPS (Photoshop Encapulated Postscript), and PSP (Jasc Paint Shop Pro proprietary file format). Some of these file formats may be able to have layers, but none of them are scaleable.

Vector Graphic File Formats

File formats that can contain unrasterized vector graphics include (but are not limited to) EPS* [encapsulated postrcipt], PS [postscript], AI [Adobe Illustrator], CNV [Canvas], P65 or PM [Adobe PageMaker], INDD [Adobe InDesign], and FH5/FH7/etc. [Macromedia Freehand]. * = Photoshop's EPS format is not a true Vector Graphics format. Files saved as Photoshop EPS files are not fully scaleable in all instances.

CMYK

The colorspace most commonly used in print media. CMYK has a smaller gamut than RGB, particularly in the so-called "true" reds, greens, and blues. Images that are created in RGB and converted to CMYK lose the colors outside the CMYK gamut.

Colorspace

A defined set of colors intended for viewing use, whether it be in print or digital format. The range of a colorspace is known as its gamut.

Gamut

The range of colors contained in a colorspace.

RGB

The colorspace most commonly used by digital displays such as TVs, Computer monitors, and projectors. RGB has a larger gamut than CMYK, particularly with regard to reds, greens, and blues. Images that are created in RGB and converted to CMYK lose any colors that are outside the CMYK gamut at the time of conversion.