Image File Formats Explained

We get asked all the time what file format do we accept, or what file format is the best. Each file type has its use and each has positives and negatives. Below, we will explain simply what the different image file types mean and what they are good for.

First group is Raster formats and the following are basic descriptions:

In computer graphics, a raster graphics or bitmap image is a dot matrix data structure that represents a generally rectangular grid of pixels (points of color) (via Wikipedia).

  • .PNG – Portable Network Graphic – Used online, typically with transparent background. Not meant for scaling up to a larger size than its pixel width or for printing.
  • .JPG (.JPEG) – Joint Photographic Expert Group – Compressed image file typically used for high quality photography and low-res images online. Doesn’t support transparency online. Not recommended for printing.
  • .TIF (.TIFF) – Tagged Image File Format – Known as the ‘print-ready’ format. Files are too big to be used online. Quality is not lost when saved or compressed. Can support layers.
  • .GIF – Graphics Interchange Format – Specifically for online use. Can be animated. Limited to 256 colors which results in smaller file sizes but lower quality.
  • .PSD – Adobe Photoshop Program – Generated by Adobe Photoshop. Never to be used online, but great for printing and sharing with graphic designers. Supports layers and transparent backgrounds but results in large file sizes.

We deal with .JPG, .TIF, and .PSD mainly here at Art Warehouse for printing purposes. When we receive a .JPG, we open it (or uncompress it) and save it as a .TIF  to maintain the quality of the file. We never do any edits to a .JPG file type and resave. This would result in recompression of the file and can degrade it. We use .TIF mainly for print as it is an uncompressed file and quality is maintained through our editing for print. We use .PSD for setting up files for special printing techniques where we may drop white ink or we have to place wording on an image. But even when we edit a .PSD file, when we are ready for print, in most cases we save the .PSD as a .TIF.

Second group is Vector formats and the following are basic descriptions:

Vector graphics are computer graphic images that are defined in terms of 2D points, which are connected by lines and curves to form polygons and other shapes. Each of these points has a definite position on the x- and y-axis of the work plane and determines the direction of the path; further, each path may have various properties including values for stroke color, shape, curve, thickness, and fill. Vector graphics are commonly found today in the SVG, EPS, and PDF graphic file formats and are intrinsically different from the more common raster graphics file formats (via Wikipedia).

We deal with vector graphics here at Art Warehouse when we need to cut out intricate or non-standard shapes on our CNC machine. We create cut files in Adobe Illustrator and import them into our CNC program to cut out shapes or graphics.

As always, if you have any questions, contact us.