File Formats & Storage

If you have been following along through this series of articles you, hopefully, have set up a set of folders to hold your newly created images. If not, please read the paragraphs on organizing folders and organizing file names. The folders refer to where you will store your images and the format is how the data is organized within the file. Books have been written on these topics, but I'll attempt to give brief overviews.

Image File Formats

The file format refers to how the information stored in the file is stored internally. Some formats compress the data and others do not. And this is where you have some important choices about how you will store your images.

If you are really not interested in the whats and whys and just want to get started, use TIFF, with LZW compression if it's available in your software. However, please do read the last section on this page, Storage & Saving While Working.

Read on to get some whys and why nots:

Some basic information: There are two kinds of graphic images. One is the Bitmap or Raster which literally displays each pixel in the image, and is created that way. The other is a Vector image which is based of mathematical algorithms. For a picture of a circle, rather storing the picture of the circle, it stores the algorithm that tells the computer how to draw the circle. Images in this format are highly scalable, and they require different software for creation and display than bitmaps. We will be looking at bitmap or raster file formats.

JPEG (jpg)

Joint Photographic Experts Group created the standards for the JPEG format back in 1992. Since sharing pictures on the Internet has become so popular, just about everyone is familiar with the JPEG (jpg) file format, and I can't imagine any modern image software that doesn't at least read that format. It has the ability of compressing your pictures into nice small lumps of data that travel nicely to and from the Internet in e-mail or on WWW pages. So, why not use that format exclusively?

The problem with it is that the compression algorithm is lossy. That is, data are lost each time the file is saved. It loses some of the details every time. Files can be over-compressed so that they become blocky looking and contain little lines outside the outlines of objects in the picture. These are called jpeg artifacts.

JPEG format is fine for the internet or even for storage if is is used only as the final result. Pictures destined for the Web should be sized appropriately and saved in that format before they are uploaded.

GIF (Graphics Interchange Format)

This bitmap image format was created by CompuServe in 1987. It allows up to 256 different colors and supports transparency, and motion. This is the format used by animated little images. This format is unsuitable for photographs or images with continuous gradations of color. It does work well for logos and small images of text. The compression in this format is lossless — that is, it doesn't discard any of the file information when it is saved.

PNG (Portable Network Graphics)

This is a raster graphics file format that supports lossless data compression. This file format is used primarily for the Internet and image designs, but not photographs. We will not need to go into any detail on this format for this project.

TIFF or tif (Tag Image File Format)

This format is used for storing bitmaps and multi-layered mixed vector and raster images. It is popular among artists, photographers, and the publishing industry. Most software that deals with images including Desktop Publishing, Word Processing, Scanning, Optical Character Recognition (OCR) can use images that are stored in this format. This is the recommended format for storage of your images. The chances are that when someone wants to use the images later, they will have software that can handle them. If your image manipulation software offers some compression choices when saving your .tif file, choose LZW. This is a lossless compression method, and other software should be able to open the file.

Others

There are a number of others that can be used such as Microsoft's BMP or WMF. These are good when using Microsoft Office applications. Adobe's PSD (Photoshop Document) format is proprietary, but that software has been so popular for so long, many applications include filters to read the format. Nearly every image manipulation program has its own proprietary format, which is convenient to use while you are working with the image, but I recommend that you use TIF for the final save.

Storage & Saving While Working

Create the folder structure that you are going to use. You might want to create an additional folder below the one where you are currently working and call it originals. Do this with each family group. That way if you learn some new procedure or get some new advanced software later, you can go back to your original scan and rework the picture if you wish.

The need to save your work often cannot be over stated. And save different versions as you progress. Before you begin, it's a good idea to save an original, unedited file. Save as yourfilename-orig.tif. Then as you finish different processes save under a new name: yourfilename-01.tif, yourfilename-02.tif ... yourfilename-n.tif.

When you are finished with each picture, you may want to keep a print-quality image (large up to 8" X 10" or larger) and also one or more smaller ones suitable for computer screen display or Web display. So you will end up with two or 3 copies of each picture. The smaller versions of you image should be saved in JPEG format for display in a Web browser.