The selected file format can have a bearing on the quality of the output. When artwork is professionally prepared, it is up to the artist to use proper file formats. Office productivity software may shield the user from controlling which formats are used internally. Though file formats can be distinguished by the document file ending, merely changing the suffix does not convert the file.
Are file formats important?
CMYK refers to cyan, magenta, yellow, and black respectively. This is the traditional four-color semi-transparent ink combination used to reproduce a wide range of colors on printing presses. (Digital printers may include additional ink colors.) Before converting images to CMYK, always save a RGB copy since color gamuts vary.
EPS (Encapsulated PostScript) is a less compact file format generally used for resolution-independent vector art that will be resized. Corporate logos and text are common examples of vector artwork (shapes defined mathematically). Over the years, the format has been expanded to support raster images (photographs). Adobe Illustrator is a common application for preparing EPS artwork.
JPEG (Joint Photographers Expert Group) graphic file format that compresses full-color bitmap graphics to obtain smaller files by averaging and discarding pixel data. Though most digital cameras produce JPEG (JPG) images, saving them as TIFF after making edits is recommended.
PDF (Portable Document Format) is a compact graphic file format viewable by Adobe Reader (free), Adobe Acrobat Professional, Adobe Illustrator and third-party PDF apps.
There are many methods for creating a PDF. The simplest way to create a PDF on a Macintosh computer running Mac OS X is to select Print from the File menu. Then press PDF the lower left corner of the Print dialog box. The button is actually a menu. Choose the first item, "Save as PDF."
PNG (Portable Network Graphics) is a bitmapped image format that employs lossless data compression. PNG was created to improve upon and replace GIF (Graphics Interchange Format) as an image-file format not requiring a patent license. It is pronounced "ping". PNG-8 supports palette-based 8-bit, grayscale or RGB images. PNG-24 supports transparency within 24-bit RBGA images. PNG was designed for transferring images on the Internet, not professional graphics, and so does not support other color spaces such as CMYK or embedded color profiles. So it is likely that color will shift when printed.
PSD (Photoshop Document) is a native Adobe raster graphic file format. PSD files, may be placed within Adobe applications like InDesign or Illustrator without conversion. However, TIFF retains the same information and is preferred in most cases.
RGB colors are made up of red, blue and green light respectively. In general, it offers a wider color range than can be reproduced with CMYK ink. It is more suitable for viewing images on a video or computer monitor. Digital cameras save images in RGB color space. Generally the pictures are converted to CMYK before printing.