
These changes to Image Alchemy 1.5.1 were made after the manual was
printed:


Use of extended and expanded memory
    If there is enough extended or expanded memory available, Alchemy
    will use it instead of the temporary files it would otherwise use
    during some conversions.  To use extended memory you must have an
    XMS driver installed in the config.sys file (such as HIMEM.SYS). 
    To use expanded memory you must have a LIM 3.2 or LIM 4.0 expanded
    memory driver (such as QEMM or 386MAX).  To disable the use of
    extended and expanded memory, set an environment variable called
    'alchemy' to 'x' (type "set alchemy=x" at the DOS prompt).

    Note that the availability of extended or expanded memory will not
    allow you to convert larger images, just save the time of writing
    and reading raw files.  We are working on a 386 version of Image
    Alchemy, which will allow 80386 and 80486 users to make use of the
    linear addressing space of those processors to convert images of up
    to 32000 x 32000 (assuming you have enough disk space).  Please
    contact us if you are running out of memory and are interested in
    upgrading to Alchemy-386.


Checking for 8514/A boards
    Alchemy will normally check to determine if there is an 8514/A
    board installed in the computer when viewing images.  However, this
    can cause problems with some network boards, as they use the same
    I/O addresses that 8514/A boards use.  To disable 8514/A checking,
    set the environment variable called 'alchemy' to '8' (type "set
    alchemy=8" at the DOS prompt).  Note that this can be combined with
    other options; for example, to disable both 8514/A checking and
    extended/expanded memory usage, use "set alchemy=8x".


New Sun Raster Output modes
    Run length compression has been added to Sun Raster output for one and
    eight bit files.  The output option for Sun Raster with compression
    is '-s1'.  The default compression for Sun Raster files remains
    uncompressed.

    In addition to the 1, 8, and 32 bit Sun raster files it is now
    possible to write 24 files.  The -24 option specifies a 24 bit
    file, the -32 option specifies a 32 bit file.


Histogram linearization
    Histogram linearization has been added to the '-S' spiff option. 
    Normally spiff stretches the histogram; if you specify '-Sb'
    instead of just '-S', then it will linearize the histogram instead. 
    Histogram linearization can produce significantly better results
    than histogram stretching for some images.


Gamma correction
    Gamma correction options have been added.  The options are (x is
    the desired gamma):
      -Gix  specify input gamma
      -Gox  specify output gamma
      -Gpx  specify gamma of palette

    To perform gamma correction, Alchemy needs to know both the input
    and output gamma.  For some file formats the gamma is known; if
    you're reading a file with known gamma, such as JPEG, PICT,
    PCPAINT, or a Targa file with the gamma field, you don't need to
    specify the input gamma.  Likewise, if you're writing a file which
    has a fixed gamma, such as JPEG, PICT, or PCPAINT, you don't need
    to specify an output gamma.  Even if reading or writing a file
    format which has a known gamma you may override the gamma by using
    the -Gi or -Go option.
    
    However, even if both input and output gamma are known based on the
    input file and the output format, you must still enable gamma
    correction for any correction to take place; you can do this with
    just '-G' (if you had specified input, output, or palette gamma,
    this would be implied).  This is because there are quite a few
    images around that have specified or implied gammas that are wrong,
    which could cause Alchemy to make matters worse instead of better. 

    Typical values for gamma are 1.0 for Macs and 2.2 for PCs.

    For example, to convert the Mac PICT file test.pic, which has a
    gamma of 1.0, to a PCX file for use on a PC (which should have a
    gamma of 2.2), use:
      alchemy -p -Gi1.0 -Go2.2 test.pic
    The input gamma could have been omitted, as PICT files have an implied
    gamma of 1.0, but it's best to include it to reduce confusion.

    To convert the file image.tga, which has a gamma of 2.2, to a GIF
    file for use on a Mac, matching the palette test.pal which was
    created with a gamma of 1.5:
      alchemy image.tga -g -Gi2.2 -Go1.0 -Gp1.5 -ftest.pal

