Editing, selection and processing - research

Source information on file types such as:

JPG: 

 JPG files, also known as JPEG files, are a common file format for digital photos and other digital graphics. When JPG files are saved, they use "lossy" compression, meaning image quality is lost as file size decreases. JPEG stands for Joint Photographic Experts Group, the committee that created the file type.

JPG files have the file extension .jpg or .jpeg. They are the most common file type for images taken with digital cameras, and widely used for photos and other graphics used on websites. Unlike GIF files, which show significant loss in photo image quality, JPGs allow for some degree of file size reduction without losing too much image quality. However, as file sizes get very low, JPG images will become "muddy." When saving photos and other images as JPG files for the web, email and other uses, you must decide on this tradeoff between quality and file size.

http://graphicdesign.about.com/od/Definitions/g/Jpg-Files.htm

TFF:  

A TIFF file, or TIF file, stands for Tagged Image File Format. TIF files are a common file format for images, especially those used on graphic design. The file extension for a TIFF file is either .tiff or .tif.

TIFF files can be saved without compression, or they can be compressed to lower file size, similar to JPG files. TIFF files are commonly used in print design and desktop publishing because they can store large, high quality images such as photos. Often, printers will prefer or require TIFF files over JPG images or other formats. TIFF files are raster images and platform independent, meaning they will work on various operating systems such as Mac and Windows. The format was developed in 1986 by Aldus Corporation and scanner manufacturers.

http://graphicdesign.about.com/od/Definitions/g/Tiff-Files.htm

PNG:

PNG, which can be pronounced "ping" or "P-N-G," is a compressed raster graphic format. It is commonly used on the Web and is also a popular choice for application graphics.

The PNG format was introduced in 1994, after the GIF and JPEG formats had already been around for several years. Therefore, PNG includes many of the benefits of both formats. For example, PNG images use lossless compression like GIF files, so they do not have any blurring or other artifacts that may appear in JPEG images. The PNG format also supports 24-bit color like the JPEG format, so a PNG image may include over 16 million colors. This is a significant difference between GIF and PNG, since GIF images can include a maximum of 256 colors.

Unlike the JPEG and GIF formats, the PNG format supports an alpha channel, or the "RGBA" color space. The alpha channel is added to the three standard color channels (red, green, and blue, or RGB) and provides 256 levels of transparency. JPEG images do not support transparent pixels and GIF images only support completely transparent (not partially opaque) pixels. Therefore, the PNG format allows Web developers and icon designers to fade an image to a transparent background rather than a specific color. A PNG with an alpha channel can be placed on any color background and maintain its original appearance, even around the edges.

While the PNG image format has many benefits, it is not suitable for all purposes. For example, digital photos are still usually saved as JPEGs, since PNGs take up far more disk space. GIFs are still used for animations since PNG images cannot be animated. Additionally, GIFs are still used on many websites since browsers only recently provided full support for the PNG format. However, now that most browsers and image editing programs support PNGs, it has become a popular file format for web developers and graphic artists.

http://www.techterms.com/definition/png

BMP:

A bitmap (or raster graphic) is a digital image composed of a matrix of dots. When viewed at 100%, each dot corresponds to an individual pixel on a display. In a standard bitmap image, each dot can be assigned a different color. Together, these dots can be used to represent any type of rectangular picture.

There are several different bitmap file formats. The standard, uncompressed bitmap format is also known as the "BMP" format or the device independent bitmap (DIB) format. It includes a header, which defines the size of the image and the number of colors the image may contain, and a list of pixels with their corresponding colors. This simple, universal image format can be recognized on nearly all platforms, but is not very efficient, especially for large images.

Other bitmap image formats, such as JPEG, GIF, and PNG, incorporate compression algorithms to reduce file size. Each format uses a different type of compression, but they all represent an image as a grid of pixels. Compressed bitmaps are significantly smaller than uncompressed BMP files and can be downloaded more quickly. Therefore, most images you see on the web are compressed bitmaps.

If you zoom into a bitmap image, regardless of the file format, it will look blocky because each dot will take up more than one pixel. Therefore, bitmap images will appear blurry if they are enlarged. Vector graphics, on the other hand, are composed of paths instead of dots, and can be scaled without reducing the quality of the image.

http://www.techterms.com/definition/bitmap

PSD:

A .PSD file is a layered image file used in Adobe PhotoShop. PSD, which stands for Photoshop Document, is the default format that Photoshop uses for saving data.  PSD is a proprietary file that allows the user to work with the images’ individual layers even after the file has been saved.

When an image is complete, Photoshop allows the user to flatten the layers and convert the flat image into a .JPG, .GIF, .TIFF or other non-proprietary file format so it can be shared.  Once a PSD image has been flatten by conversion, however, it cannot be converted back to PSD and the user can no longer work with the image's layers. It is important, therefore, so always save the .PSD file and not overwrite it during conversion.

http://whatis.techtarget.com/fileformat/PSD-Adobe-Photoshop-default

AI:

Adobe Illustrator is a program used by both artists and graphic designers to create vector images. These images will then be used for company logos, promotional uses or even personal work, both in print and digital form. So what is Adobe Illustrator used for? It is typically used to create illustrations, charts, graphs, logos, diagrams, cartoons of real photographs, and more. While the program may be difficult to understand initially, the final product will be well worth the learning curve.

Creating vector images allows you to create clean, beautiful works of art that can be scaled up and down infinitely without ever losing quality. Have you ever created an image in Adobe Photoshop, and then realized that you should have created it three times larger than you did? You go into Image Adjustments, increase the size, and … oops. The image is now pixelated and looks horrible. If the image was too small to begin with, you’ll need to start all over again. The same does not remain true for Adobe Illustrator. Unlike the familiar gif, jpeg, tiff, etc images – known as raster images –  vector images are not made up of a grid of pixels. They are instead created by paths – a combination of a starting point and an ending point with a combination of shapes, angles and lines in-between. These paths relate to each other by mathematical formulas, allowing them to be scaled and rescaled infinitely.

https://www.udemy.com/blog/what-is-adobe-illustrator-used-for/

WMF: 

In Windows, a metafile is a file that contains information regarding one or more other files. Called a Windows Metafile Format (WMF), it is commonly a graphics file format, containing information for vector graphics or bitmap files. The WMF contains a list of function calls that Windows uses in its Graphics Device Interface (GDI) layer to display images on a computer monitor.

The WMF was originally released around 1992 as a 16-bit format file for Windows 3.0. A 32-bit version was released in 1993 and called an Enhanced Metafile (EMF). For Windows XP, the Enhanced Metafile Format Plus Extensions (EMF+) format was released. There are also compressed WMFs, called Compressed Windows Metafile (WMZ) and Compressed Windows Enhanced Metafile (EMZ).

http://www.computerhope.com/jargon/w/wmf.htm