When we deal with different image formats, we sometimes come across situations when one and the same format has several files extensions (JPEG and JPG, TIFF and TIF, etc). But some image formats are more tricky – the same file extension can mean very different things. One of the image formats serving as an example of this is CALS with the file extensions cals, CALS, cal, CAL. The CALS image format is applied in very diverse situations. One of its variations was designed for military use – for data transference between the military and the federal government. Hard to say how much confidential information was exchanged, but probably this is one of the reasons for very limited support was provided for opening such files. Another area of use of the CALS image format is calendar and scheduling programs as well as postcards creation software. Not surprising that such diverse areas of application make this format one of the most problematic for opening and processing. When a successful user is able to open the CALS format, the most reliable way to convert it is to convert CALS to PDF. PDF is software independent, so regardless of the device you are going to use for viewing PDF files, they will look exactly the same. There are type I and type II CAL image files used today. Type I, stores a single compressed image file and Type II contains multiple image files in each. Type II may store image data in a compressed, raw or tiled format. Unfortunately, ImageConverter Plus cannot provide guaranteed support for CALS to PDF conversion. Due the diverse nature of the CALS image format this may cause difficulties, but we encourage our users to send their CALS format file variation to our support service.