OpenMAW is a program that was written by Russell Bozian that will convert Minolta RAW files to TIFF.

This is an alpha version, and is freeware, thanks to Russell. Please contact Russell if you have questions about this, I probably can't answer them! Use at your own risk. E-mail Russell


Version 0.95 now on line October 12, 2002


Adds support for Minolta D7u firmware upgrade, D7i, D7hi. Now appends color-balancing coefficients to end of output filename.  Dropped faster, cruder bilinear interpolation option since highest quality  variable-gradients demosaicing now runs in less than 4 seconds per image on 1000mhz Pentium.

Click to Download software (OpenMawInstall.exe about 90K), release notes are in the package.

You may also need VBRUN60, the Visual Basic runtime module, if you don't already have it on your system.

Click here to download VBRUN from the Imperial Microsoft Website.


What is OpenMaw?
OpenMaw is a freeware project, focused on the Minolta Dimage 7 (and eventually D5) ".MRW" digital camera, to make relatively-unprocessed image files by converting the .MRW "raw" file output from those cameras.
The Minolta Dimage5/7 digital cameras take ordinary Jpeg and .TIF photos. However these photos have been processed extensively by the camera and/or Minolta DIVU image viewer software, whether you want the processing or not. The unavoidable Minolta Jpeg/DIVU processing includes Minolta imposing a certain "white balance" to the image colors, a certain contrast and brightness, sharpening level, etc.

The OpenMaw projects gives users an alternative to the "canned" Minolta image processing of your images. Minolta has thoughtfully provided the option for users to take 10-megabyte .MRW "raw" files, which are little more than a heap of numbers describing the relative intensity of red,green and blue dots of light scattered across the Minolta's 5 megapixel image sensor.

The OpenMaw utilities let users do the minimal amount of image manipulation necessary to make the camera's photos be smoothly-full-color TIF images. You want minimally-processed images when you feel that your sophisticated and favorite photo editor can do a better job, under your wise guidance, of "developing" these images to normal color and contrast than the pre-fixed Minolta manipulations.

These raw images are not for the faint of heart. They tend to look greenish and dark, especially when emerging from the OpenMaw.exe utility. The Mrw2tif.exe utility has several built-in controls to help you produce a closer-to-finished output photo without further editing.

The OpenMaw.exe is a more stripped-down utility whose only concern is doing the best job possible of "de-mosaicing" the checkerboard red/green/blue data that comes fresh from the Minolta's CCD sensor. As of this writing you might favor OpenMaw.exe over Mrw2tif if you like the idea of the images emerging with an ICM input colorspace pre-attached, or you like clicking your way through a graphical user interface. The plan is to eventually merge the two programs into a single utility that combines the strengths of both.

Mrw2tif.exe, in contrast, offers equal-or-better de-mosaicing of color, plus several powerful contrast and brightness output options. Mrw2tif also offers a choice of de-mosaicing algorithms for your educational enjoyment, and/or to speed up processing.

OpenMaw, the focus of this readme.txt, can be invoked from the command line if the default settings (there are very few options) are to your liking. Or you can run OpenMaw "interactively" if you prefer pointing and clicking at things.

The overall goal of the OpenMaw (Open Minolta rAW file converter) project is to provide a better alternative to DIVU (the Dimage Image Viewer utility, high-quality but idiosyncratic, supplied with the camera) with more "film development" features, more flexibility and the highest possible image quality. Image quality is the first and foremost priority of any OpenMaw product, so don't expect any speed demons here.

This version of OpenMaw is an alpha release, i.e. not finished. The utility is has plenty of rough edges, particularly with regards to not handling incorrect file specifications, so use at your own risk. As of 2001 November 8 OpenMaw.exe v0.92 seems to have weird checkerboard colors in very bright parts of the images (to be fixed shortly). We would appreciate it if you report any other bugs or errors encountered to the authors.


The only feature you may specify on the OpenMaw.exe command line is a single input-file specification. For example

  OpenMaw C:\My Documents\from camera\pict*
would tell OpenMaw to convert all photos in the indicated folder that start with the letters p then i then c then t to be converted from 10meg .MRW raw images into full-color, 28 megabyte TIF files with new names like

Command-line-started OpenMaw always embeds the Minolta Dimage7 (raw) input colorspace into the TIF file, generally a good thing. The Minolta colorspace is tiny and surprisingly accurate, considering the bad impression many of us have of the Minolta default JPeg output.


The current feature set of OpenMaw includes:
-Threshold-based Variable number of gradients bayer interpolation (i.e. interpolation meaning full-color development from the inherently patchwork color info of single-sensor digital cameras in the year 2001.)
-Converted image saved as 48-bit tiff files.
-Converted image by default has the Minolta Dimage 7 (raw) colorspace embedded in them that "ICM-aware" image handlers need to properly interpret the D7 colors and contrast.
-OpenMaw project components are freeware, no registration needed! As to why the program authors do this work without financial reward, note that they are avid photographers who simply want to "develop their own film". Thus the creation of the software is its own reward for them, as well as an education in digital imaging.


Installing and using OpenMaw:
Run OpenMawInstall.exe. Extract the contents of the Zip-file to any directory you like to install programs. The default location that OpenMawInstall.exe puts the program files is "c:\program files\OpenMaw".

You can convert images in several ways:
-Place OpenMaw.exe (and its required ".omw" resource files) somewhere in your path and execute it in an MS-DOS command line window from the directory where the .mrw-files you want to convert are. Specify the exact filename or wildcard specification on the command line after you type the name of the program. You do not need to type the ".mrw" part of the filename, that's what OpenMaw is looking for anyway. Example:

   OpenMaw C:\pict0001
-Place OpenMaw.exe (and its required ".omw" resource files) anywhere and double-click it. OpenMaw will come up with a pretty simple screen with a couple of minimal and self-explanatory options.

-Place a shortcut to mrw2tif.exe on the desktop. You can drag images ONE AT A TIME to the icon to convert them. The converted image will be saved in the same directory as the original image.


OpenMaw, and its cousin, Mrw2tif, are supplied on an as-is basis. The authors offers no warranty of its fitness for any purpose whatsoever, and accepts no liability whatsoever for any loss or damage incurred by its use. OpenMaw and Mrw2tif are not supported products. The authors accepts no commitment or liability to address any problems that may be encountered in using it; however, OpenMaw and mrw2tif are continually being developed and improved, so the authors are always interested to hear about any bugs or deficiencies. Once is usually enough.

Using And Distributing OpenMaw and mrw2tif
OpenMaw and Mrw2tif may be freely used for any purpose. You may use it privately or in the course of your work; there is no fee, and no registration is required. You may distribute it to anyone, and you may place it on any archive or bulletin board system. You may not charge anyone for it other than a reasonable fee to cover your distribution costs.

Normally, you should distribute mrw2tif or OpenMaw in the form as supplied by the authors; however, you may repackage it to suit the conventions and needs of an archive or bulletin board system. Mrw2tif/OpenMaw may be distributed as part of any commercial product without a prior licence agreement, although no extra cost can be charged for inclusion of mrw2tif.exe or Openmaw.exe or other OpenMaw project components. Mrw2tif/OpenMaw may be reviewed for any publication, whether in hard copy or electronic form, without the author's prior permission.

Contacting the Authors
Mrw2tif and OpenMaw are still under development by the authors, Paul K. Hansen and Russell Bozian. If you have comments or suggestions please send eMail to:
for Mrw2tif, or
for OpenMaw.


Internet home page for program updates:
Bryan Biggers kindly hosts updates for OpenMaw.exe at:

Please check for the newest updates of mrw2tif on this webpage:


Version History mrw2tif
v0.2a (7.November 2001)
-First public release


v0.92 (8.November 2001)
-First public release

v0.93 (11.November 2001)
-allows .omw resource files to be stored anywhere the openmaw.exe program resides, not just in c:\