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Name all the types of file formats:
JPG, GIF, TIFF, PNG, BMP
A big reason that so many file formats exist is…
The need for compressing, or making the files smaller for Internet downloads, emailing, or displaying the files.
With modern digital cameras the image files can be quite _____. ______ files mean more disk usage and slower downloads.
Large/(r)
Define Compression:
A term used to describe ways of reducing file sizes with minimal impact on the final look of the file.
Another factor that impacts the file format selection is…
The number of colors contained in the image. A logo file with crisp lines will have fewer colors than a picture with many shades of the same color.
Define Lossless VS Lossy Algorithm:
A lossless compression algorithm discards no information and can be saved many times by your editing program. The program saving the file may use algorithms to look for efficient ways to save an image without making compromises in accuracy.
By contrast, "lossy" algorithms create some degradation in the image in order to achieve a smaller file size.
The simplest pictures may contain only two colors, such as…
Black and white. A black and white image will only need 1 bit, a computer term used to refer to how data is stored, to represent each pixel.
Early PC video cards only supported 16 fixed colors while later cards went to 256 and now modern cards can display 16 million colors without restriction.
Since the human eye has trouble distinguishing between similar colors, 24 bit or 16 million colors is often called…
TrueColor and is the realistic limit.
Define TIFF File Formats:
Exclusively as a lossless image storage format that uses no compression at all and is compatible with a variety of editors. Larger than other file types.
Summary: Means better quality. However, the file size is huge compared to even the best JPG setting, and the advantages may not be noticeable. Use it as a "working" file format when you may be sharing it with people with other editing software.
Define PNG File Formats:
Also lossless and is growing in popularity. As opposed to the TIFF format this one will take advantage of patterns in the image which can be used to compress the file. The compression is 100% reversible, so the image is not altered.
Summary: Superior to GIF. It produces smaller files and reproduces more colors. Also supports partial transparency. Use this when an image with large areas of exactly uniform color and contains more than 256 colors.
Partial transparency can be used for many useful purposes, such as…
Fades and antialiasing of text.
Define GIF File Formats:
Creates a table of up to 256 colors from the pool of 16 million. If an image has fewer than 256 colors, this one can render the image exactly. When the image contains many colors, software that creates these files will use one of several algorithms to approximate the colors in the image with the limited palette of 256 colors. The best algorithms will search an image to find an optimum set of 256 colors.
Summary: Do NOT use these files for photographic images, since it can contain only 256 colors per image.
Sometimes the nearest color will be used to represent each pixel, and sometimes a process called "error diffusion" will be used to…
Adjust the color of nearby pixels to correct for the error in each pixel.
What two ways does the GIF File Format achieve compression?
First, by reducing the number of colors of color-rich images which reduces the amount of data stored about the image and secondly it replaces commonly occurring patterns.
This is why this format works so well for logs and drawings. These files can be animated and include transparency.
Define JPG File Formats:
Optimized for photographs and images with a wide range of colors that contain many, many colors. These can achieve great compression ratios while maintaining great image quality for the intended use. These work by discarding picture information that the eye is least likely to notice. The information stored is 24 bit color. One beauty of these file formats is that the degree of compression is adjustable.
Summary: Excellent format for digital photographers to store their final image and to reduce the size of their image for emails and web posting.
At moderate compression levels of photographic images, it is very difficult for the eye to tell that the image has changed. Thats why…
Compression factors of more than 25 are often quite acceptable.
Better graphics programs, such as Paint Shop Pro and Photoshop, allow you to view the image quality and file size as a function of compression level, so that you can choose the balance between quality and file size.
Define the most common format for nearly all photographs on the web:
JPG; It will render excellent quality at higher compression settings. When editing, use your software's proprietary format until finished, and then save a copy in the JPG format. Digital cameras typically save in a JPG format by default.
Define RAW File Formats:
An image output option available on many medium quality to professional digital cameras. The beauty of this file format is that it allows you to have more ability to edit the images than other formats. The disadvantage is that there is a different type of this format for each manufacturer, and so you may have to use the manufacturer's software to view the images.
(Some graphics applications can read some manufacturer's RAW formats.)
Define DNG File Formats:
A universal RAW image format for saving digital photos in an uncompressed format; developed by Adobe Systems as a RAW image archival format and is supported by many image viewing and photo editing programs.
Define BMP File Formats:
An uncompressed proprietary format invented by Microsoft. Don't use it.
Define PSD, PSP, etc. File Formats:
Formats used by graphics programs. Photoshop's files have the PSD extension, while Paint Shop Pro files use PSP. These are the preferred working formats as you edit images in the software.
If you are planning to share these files save them into a TIFF format.
GIF, PNG, and JPG are the formats used for…
Nearly all web images.
PNG has only recently became widely supported so most of the web images are one of the other two formats.
Define EPS File Formats:
An Encapsulated PostScript language file format that can contain both vector and bitmap graphics and is supported by virtually all graphic, illustration, and page-layout programs. This format is used to transfer PostScript-language artwork between applications. This format supports Lab, CMYK, RGB, Indexed Colour, Duo tone, Grayscale, and Bitmap color modes, but does not support alpha channels. It does support clipping paths. To print EPS files, you must use a PostScript printer.
Define DCS File Formats:
Desktop Color Separations format, a version of the standard EPS format, lets you save color separations of CMYK images.
Define PDF File Formats:
The Portable Document Format is a flexible, cross-platform, cross-application file format. Based on the PostScript imaging model, these files accurately display and preserve fonts, page layouts, and both vector and bitmap graphics. In addition, these files can contain electronic document search and navigation features such as electronic links. These files are created using applications like Adobe Acrobat and Adobe Illustrator, and can contain multiple pages and images.
Define PICT File Formats:
This format is an old, Mac-only bitmap format, similar to BMP for Windows. This is not often used today.
