Converting Camera RAW Image Formats under Windows Mac OS X and Linux Freeware and Plug Ins

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If your digital camera uses a proprietary file or RAW file format to capture images, you should use it. Taking photos as digital raw data will result in a higher-quality image after correction, particularly when compared to photos taken in the highest-quality JPEG format. Saving images in their native camera or RAW format will also ensure that you'll get the best possible quality when you archive the originals.

Since version 2.2.6, GIMP supports RAW formats, so you can directly open and edit RAW formats with the program. Unfortunately, GIMP does not work with all proprietary camera RAW formats, so you'll need to make sure it can read your camera's format. At the end of section 5.6, you will find a list of RAW formats GIMP can read.

If GIMP can read the RAW format your camera uses, the images will be available with a 24-bit color depth (8 bits per color channel). Remember to save the finished image in a high-quality standard format, such as TIFF or PNG.

RAW formats offer more than a means to optimally save your photos. RAW also permits you to adjust the color and brightness settings, using the RawPhoto or UFRaw plug-in (explained in a bit) with a color depth of 16 bits per color channel. For example, this means that you can edit underexposed photos with more efficient options than those currently offered by GIMP with only 8 bits per channel. Thus, working with digital RAW images is called developing and refers primarily to adjusting color and brightness values, just as it does in analog photography. RAW formats are sometimes referred to as digital negatives.

If you have Windows or Mac OS, you can develop photos in RAW format by using the software that came with your camera, or you can use one of the plug-ins for GIMP.

The Unidentified Flying Raw (UFRaw) by Udi Fuchs and the dcraw command-line program by Dave Coffin are plug-ins that are available for Windows, Linux, and Mac OS X. They enable you to develop digital negatives with 16-bit color depth rather than in the lower quality offered by GIMP (8 bits per channel). You can edit the color and brightness settings as well as the white balance with UFRaw. It functions with its own dialog box before the image is passed on to GIMP for further editing. Once you've installed UFRaw, it can be used in three different ways: first, as an independent program that can edit and save digital negatives; second, and most interesting, when you open RAW images, UFRaw operates within GIMP; and third, the program contains ufraw-batch, a function that can convert several RAW files simultaneously.

You can download UFRaw for Windows, Mac OS X, and Linux on the following website: It is already included in the distributions of GIMP for GIMP on Mac OS X (http://gimp.

The installation for Windows is rather easy. Just double-click the installation file and follow the instructions. No additional downloads of dcraw are necessary as the program is already integrated into UFRaw.

After installing, UFRaw can be used both as an independent program and as a plug-in for GIMP. If you want to use UFRaw independently or as a GIMP plug-in, you must have GIMP already installed because GIMP's installation file contains the GIMP Tool Kit (GTK+). In order to function, UFRaw needs GTK+.

In section 2.2 you will find a short introduction to editing digital negatives with UFRaw as a GIMP plug-in and handing it over to GIMP. Furthermore, you will find detailed instructions on how to use UFRaw on the following website:

RawTherapee is another free software package for Linux and Windows. It is an extensive and comfortable program used to develop RAW images. RawTherapee doesn't work as a GIMP plug-in, but due to its features and its functional range, it is a good alternative to UFRaw. You can develop your RAW photos comfortably and thoroughly and pass them on to GIMP for editing.

RawTherapee is not only a great RAW developer, it also does most common white balance corrections, tone adjustments, input sharpening, and noise reduction in the JPG, TIF, and PNG file formats. It is almost an autonomous image editing program. You can find the download and information regarding handbooks on the website http://www.rawtherapee. com. There is an introduction to RawTherapee in section 2.2.1.

You can thank Pawel Jochym for creating an excellent Linux tool. He wrote a special plug-in called RawPhoto that acts like a RAW file import filter for the GIMP, using Dave Coffin's dcraw command-line program.

dcraw is included in UFRaw and RawTherapee.

You can visit Dave Coffin's home page at http://www.cybercom. net/~dcoffin/index.html. You will find links to download the program file for dcraw.c, the plug-in for Linux platforms. This plug-in has to be installed before installing RawPhoto. The download for Linux can be accessed at or rpm2html/search.php?queery=rawphoto. There aren't any versions of RawPhoto available for Windows or Mac OS. However, if you are interested in dcraw for Windows or Mac OS, you can download files from http://www.

Visit the website at and navigate to "Decoding raw digital photos in Linux". You'll find installation instructions for Linux, as well as some helpful hints.

If neither GIMP nor any of the plug-ins mentioned here can read the RAW format of your camera, you can work around the problem by converting your images to a "readable" file format, such as TIFF or PNG, using either the software that came with your camera or a third-party application.

If no software is available from your camera manufacturer, you can use IrfanViewer. IrfanViewer is a universal image viewer, but it can do much more than view images (see section 1.4.4). In addition to the main program, there is a secondary file containing plug-ins that support several proprietary camera formats. I recommend that you download and install both of these files.

With these two files installed on your computer, IrfanViewer can read the following file formats:

CAM—Casio Camera File (JPEG version only) CRW/CR2—Canon CRW files

DCR/MRW/NEF/ORF/PEF/RAF/SRF/X3F—camera formats KDC—Kodak Digital Camera files PCD—Kodak Photo CD RAW—RAW image files

After opening an image, you can rename and save it in a suitable file format, such as TIFF or PNG, using the File > Save as menu options. Alternatively, you can use the batch-processing feature of IrfanViewer to simultaneously convert large numbers of images by going to the File > Convert > Rename Batch menu.



Highest Quality Format Gimp

Figure 1.12

Using the batch conversion and file renaming options of IrfanViewer

Figure 1.12

Using the batch conversion and file renaming options of IrfanViewer



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  • Sanni
    How to convert negatives to digital photos using g.i.m.p.?
    9 years ago

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