Basic Printer Options

    These options control basic printer functions.

        Printer Model

                Select the printer to use.  It must be supplied in all
                cases.

        Page Size

                Select the paper (media) size to print to.  Some
                printers support custom paper sizes, while others only
                support certain preset sizes.

                Note that this option refers to the actual size of the
                media, not the printable area.  For example, selecting
                A4 refers to actual A4 paper, whatever the margins may
                be.

        Double-Sided Printing

                Otherwise known as "duplex" printing, this is offered
                for printers capable of printing on both sides of the
                page.  In addition to single-sided printing, there are
                two modes of duplex operation: the page may be flipped
                over its long edge (like a book), or over the short
                edge (like a note pad; this is sometimes referred to
                as Tumble).

        Media Type

                Select the kind of paper or other media being printed
                to.  This enables the printer and driver to be set up
                appropriately for the kind of paper in use.

                It is important to set the Media Type to the correct
                value if possible, or if not to a closely related
                medium.  The printer may need to know what kind of
                media is in use to determine how to feed the paper
                correctly; the driver needs to know in order to select
                the right output settings.

        Media Source

                Select the source of the paper or other media.  This
                option is offered with printers that have multiple
                feeds, for example multiple paper bins, manual feed,
                printing directly to a CD, etc.

        Ink Set

                Select the kind of ink in use in the printer, for
                printers offering different optional inks (for
                example, ink designed for matte paper vs. ink designed
                for glossy paper).

        Borderless

                Select whether to print with borders or not, for
                printers with the capability to overprint the page.
                This is otherwise known as "full bleed".

        Enhanced Gloss

                Some newer printers have a cartridge of "gloss
                enhancer", which helps solve the problem of pigment
                inks having an inconsistent "luster" on glossy paper.
                Use this option to enable use of the gloss enhancer.


Advanced Printer Options

    These options control more advanced printer-specific behaviors.
    Generally it's not necessary to adjust these options.

        Resolution

                Select the resolution to print at (dots per inch).  In
                general, higher resolutions produce better quality, at
                the expense of additional time.

                As a general rule of thumb, on laser printers and
                older inkjet printers resolutions of 300 DPI or
                thereabouts provide draft quality; lower resolutions
                provide economy draft quality and cannot produce solid
                black.  Resolutions of 600 or 720 DPI produce good
                quality output; higher resolutions are useful for very
                high quality image or graphic output.  Newer inkjet
                printers, with smaller ink drop sizes, typically
                require higher resolutions to produce acceptable
                output; in some cases even 1440x720 DPI does not
                produce good quality.

                Users of Epson inkjet printers have another setting
                available: the Quality option can be used to
                indirectly control the printer resolution, among other
                things.  This offers a simpler way to control output
                quality.

        Ink Type

                Select which subset of inks to use for printing.  For
                example, on a photo printer with additional light cyan
                and light magenta inks, it's possible to print with
                only the standard cyan, magenta, yellow, and black
                inks.

                Normally there is no reason to use any setting other
                than the default.  Reasons why one might want to use
                it include:

                1) Some black inks are not compatible with certain
                   glossy papers.  If the black ink smudges on your
                   paper, you may elect to use an option without black
                   ink (a "composite" setting).

                2) Some inks or paper/ink combinations produce color
                   shifts when the light inks are used.  If your
                   chosen combination produces unacceptable color
                   shifts or color casts, you may prefer to use the
                   Four Color Standard option, which will generally
                   yield more consistent color at the expense of
                   "grainier" output.

        Printing Direction

                Most inkjet printers can print either unidirectionally
                (the head prints only when moving in one direction) or
                bidirectionally (the head prints when moving in both
                directions).  Bidirectional printing is generally
                faster, since the printer is printing at all times
                rather than wasting much of the time returning the
                head to the starting position.  On many printers,
                however, unidirectional printing produces better
                quality output than bidirectional printing.

                The standard setting for this option adapts to the
                printing resolution.

        Laminate Pattern

                Some dye sublimation printers are able achieve better
                durability of output by covering it with transparent
                laminate surface. This surface can be of different
                patterns: common are matte, glossy or texture.


Specialized Printer Options

    These options control unusual printer features.  They may be
    useful in certain circumstances.

        CD Hub Size

                This setting may be used on printers with the
                capability to print directly to a CD.  Depending upon
                your choice of media, you may be able to safely print
                all the way to the inner hole of the CD, or you may
                not be able to print any closer than the hub about an
                inch from the center.

        CD Horizontal Fine Adjustment
        CD Vertical Fine Adjustment

                These settings allow you to shift the position of the
                print while printing to a CD.  If you find that your
                print is not centered on the CD surface, you may need
                to adjust these setting to compensate.

        Interleave Method

                Most inkjet printers create the printed image using
                multiple overlapping passes of the print head.  On
                many printers this function is performed within the
                printer itself and cannot be adjusted, but with many
                Epson inkjet printers (and some others), this is
                performed by the driver or may be specified to the
                printer.  One advantage of the multiple overlapping
                passes is that it can hide small differences between
                the individual print head nozzles, which would
                otherwise be visible as banding.  The different
                interleave methods are different strategies for
                for performing this overlapping; some are better at
                hiding the banding than others.  They all require the
                same amount of time to print.

                Generally it is not necessary to adjust this; in some
                cases, depending upon your printer, you may find that
                one pattern or another performs better.

                On Epson Stylus Pro printers, this option allows
                specifying different overlap patterns within the
                printer.  In this case, the choice of overlap pattern
                may affect both the printing time and the quality to a
                significant degree.

        Adjust dot size as necessary

                This option is provided on many Epson inkjet printers
                to allow you to use larger ink drops than those
                normally used for the resolution chosen.  This may be
                necessary if you use certain kinds of media or for
                some reason wish to use much more ink (higher density)
                than the default.  It should not be necessary to use
                this option.


Basic Output Controls

        Output Type

                This option specifies whether to print in color or
                black and white/grayscale (using only black inks).
                Black and white printing is generally faster than
                color printing, even if the item being printed is
                entirely black and white.  However, printing with only
                black ink may yield a "grainy" appearance.

        Color Correction

                This selects the choice of color correction method
                within Gutenprint.  The following options are offered:

                * DEFAULT: Select a color correction mode appropriate
                  for the document type being printed.

                * HIGH ACCURACY: Apply optimum color correction to the
                  output to produce the best color quality.  This
                  corrects the hue, brightness, and saturation
                  (brilliance of color).  This is the normal setting
                  to use for printing photographs or graphics if you
                  are not using any external color management.

                * BRIGHT COLORS: Apply color correction to the output,
                  but generate more brilliant colors in some cases.

                * CORRECT HUE ONLY: Apply color correction to the
                  output, but correct only the hue.  This option does
                  not correct brightness and saturation.

                * UNCORRECTED: Do not apply any color correction to
                  the output beyond generating linear output.  This is
                  the best setting to use when utilizing external
                  color management; the high accuracy modes employ
                  correction algorithms that may not work well with
                  color management.

                  Note that if you use color management you should use
                  profiles created with Gutenprint and with the exact
                  settings that you plan to print with.  Profiles
                  provided by the printer vendor are calibrated for
                  the vendor's driver, which may not be identical to
                  Gutenprint's calibration.

                * DESATURATED: Print in pure grayscale, but using
                  color inks.  The result is somewhat different from
                  printing in black and white using the Output Type
                  option -- the driver may use color ink, which
                  generates smoother output and may yield better
                  results on many papers.

                * THRESHOLD: Convert all colors to fully on or fully
                  off, eliminating all gradual tonal gradations.  The
                  result is that the output will consist of all very
                  pure colors.

                * DENSITY: Correct only the amount of ink ("density"),
                  otherwise performing no correction at all, even for
                  linearity.  Prints made with this option will
                  usually be very dark if no other color management is
                  used.  This may be useful if you are printing in 16
                  bit precision or are using your own linearization
                  curves.

                * RAW: Perform no correction at all, even for
                  density.  Prints made with this option will be very
                  dark and may bleed (or even puddle!) ink if not used
                  with external color management and linearization.
                  This option may be useful if you are using external
                  color management and linearization to get extremely
                  saturated dark colors by using more ink in
                  individual channels.  It should be used with extreme
                  caution, as it is very easy to damage the printer if
                  you are not careful.

                * PRE-DITHERED: Interpret each pixel as the actual
                  size of each drop to be printed.  Legal values of
                  the drop sizes differ between printers; all printers
                  support 0 (no droplet) and 1 (the largest droplet).
                  Some printers support four levels (0, 1, 2, and 3).

        Image Type

                Specify the option that best describes your print job.
                Your choice here will affect the processing of the
                print job.  Currently available settings are:

                * TEXT: Optimize the output for printing black text
                  with no graphics.  This option results in crisp
                  output and is very fast, but will yield very poor
                  results with any color or grayscale graphics.

                * GRAPHICS: Optimize the output for printing color
                  graphics.  This option will generate smooth, bright
                  output.

                * MIXED TEXT AND GRAPHICS: Optimize the output for
                  printing a mixture of text and graphics.

                * PHOTOGRAPH: Optimize the output for printing
                  photographs.  This option will generate smooth
                  tones and high quality colors, but will be slower
                  than the other options.

                * LINE ART: Optimize the output for printing black and
                  white line art with intricate detail.

                * MANUAL CONTROL: Do not bias the output at all; use
                  only the settings specified by the user.

        Print Quality

                Specify the desired output quality using convenient
                presets.  Where this option is available, Gutenprint
                will automatically adjust the printing resolution and
                other options to generate the desired quality.
                Settings chosen with this option may be overridden by
                explicitly setting other settings, such as resolution.
                Not all printers offer all of these options.
                Currently available settings, in increasing order of
                quality, include:

                * FAST ECONOMY: Use the fastest printing mode
                  available on the printer to print with a minimum
                  amount of ink.  This option will produce very washed
                  out colors and grays, and will typically be
                  extremely grainy and streaky.

                * ECONOMY: Print very rapidly with a reduced amount of
                  ink.  This option will produce washed out colors and
                  grays and will typically be quite grainy and
                  streaky.

                * DRAFT: Print low quality draft output quickly.  This
                  option will typically produce acceptable colors with
                  some amount of grain on plain paper, but will
                  typically produce washed out and grainy output on
                  high quality papers.  On some printers this may
                  employ a special draft mode to print especially
                  quickly at the expense of color fidelity.

                * STANDARD: Print at a normal quality level for text
                  or text/graphics on plain paper or basic inkjet
                  paper.  This option will typically produce
                  acceptable colors, but on high quality papers the
                  output may be grainy or somewhat washed out.  This
                  option may also be useful for printing draft copies
                  of photographs on coated inkjet paper.

                * HIGH: Print final copies of text or text/graphics on
                  plain paper or inkjet paper.  This option will
                  typically produce good color quality, but the
                  quality may not be optimal for photographs on glossy
                  paper.  This option may also be useful for printing
                  draft copies of photographs on glossy paper.

                * PHOTO: Print photographs on glossy paper or very
                  high quality text, text/graphics, or line art on
                  high quality paper.  In the latter application this
                  will produce output close to laser printer quality.
                  On the highest quality premium papers the result may
                  still be a bit grainy.

                * SUPER PHOTO: Print photographs on glossy paper with
                  very high quality.  This will generally yield very
                  good results on high quality premium paper but may
                  be overkill on other papers.  This option is only
                  offered on printers capable of producing very high
                  quality output rivaling traditional photographic
                  printing.  This option may also be appropriate for
                  very intricate line art, where the required
                  resolution may exceed the capabilities of laser
                  printers.

                * ULTRA PHOTO: Print photographs on premium papers
                  with extremely high quality.  This option is only
                  offered on printers capable of producing extremely
                  high quality output matching or exceeding
                  traditional photographic printing.

                * BEST: Print with the best quality available on the
                  printer for the application chosen.  This may be
                  equivalent to one of the other settings; on a very
                  few printers the resolution may exceed that of Ultra
                  Photo mode.

                * MANUAL CONTROL: Do not adjust the settings at all;
                  use only the settings specified by the user.


Basic Output Adjustments

        Saturation

                This option controls the vividness of the output
                color; higher values produce more vivid colors.  Very
                low values produce muted colors; setting this to zero
                produces gray.

        Contrast

                This controls the contrast of the output.  Lower
                values produce less tonal range in the midtones
                (lighter colors become darker, and darker colors
                become lighter), which may allow for more definition
                in the highlights and shadows.  Higher values do the
                opposite: lighter colors become even lighter, while
                darker colors become even darker.

        Brightness

                This control adjusts the general brightness of the
                print; higher values produce generally lighter output,
                while lower values produce generally darker output.
                White and black are not changed; colors also retain
                their hue and saturation.


Advanced Output Adjustments

    These controls adjust more specialized settings.

        Dither Algorithm

                Since inkjet printers have a very limited set of ink
                colours, most colours have to be produced by mixing
                the available inks.  This is done by printing patterns
                of very small dots, fooling the eye into seeing many
                different shades.  This process is called "dithering";
                several different patterns are available, with
                trade-offs between speed and quality.  The following
                dither algorithms are currently available.  If no
                algorithm is selected, the package chooses an
                appropriate one based on other option settings.  The
                following algorithms are currently available,
                generally in increasing order of quality.

                * VERY FAST: This algorithm produces very rough,
                  patterned output, but is extremely fast.  This
                  generally yields poor results on modern inkjet
                  printers, particularly models that offer multiple
                  drop sizes, but it can yield very good results on
                  laser printers.  It is a good choice for printing
                  text or line art where no grayscale or color is
                  used, and also works very well when Threshold color
                  correction is used.

                * FAST: This algorithm also produces output with very
                  strong diagonal patterns.  It is also quite fast.
                  It produces somewhat better results on modern inkjet
                  printers that offer multiple drop sizes, but offers
                  no advantages on laser printers or old (generally
                  pre-1999) inkjet printers.

                * ORDERED: This algorithm produces much smoother
                  output than Fast or Very Fast.  It is somewhat
                  slower than those algorithms.  It utilizes a fixed
                  pattern that is generally free of artifacts.  It is
                  an excellent choice for printing draft copies of
                  business graphics or photographs (charts, etc.) due
                  to its lack of artifacts.

                * ADAPTIVE HYBRID: This algorithm produces slightly
                  smoother output than Ordered dithering, at some cost
                  in performance.  It uses a fixed pattern in
                  highlights to avoid artifacts, and error diffusion
                  at higher densities to reduce noise (which looks
                  like roughness in texture).  It is an excellent
                  choice for printing business graphics due to its
                  lack of artifacts and smooth texture in darker
                  tones.

                * EVEN TONE: This relatively new algorithm yields
                  excellent smoothness in all tones (light, midtone,
                  and shadow), but is considerably slower than most of
                  the other algorithms.  It is somewhat prone to
                  artifacts, including "tearing", at sharp boundaries.
                  This algorithm is well-suited for printing
                  photographs, but is not as suitable for printing
                  solid-tone graphics.

                * HYBRID EVEN TONE: This algorithm combines Even Tone
                  and Ordered dithering to yield smooth results with
                  fewer artifacts than Even Tone dithering, but is
                  even slower than standard Even Tone.  It uses the
                  fixed pattern of Ordered dithering to break up the
                  artifacts of Even Tone dithering.  The result is not
                  quite as smooth as pure Even Tone, but the reduction
                  of artifacts makes this an excellent choice for
                  photographs or photographs mixed with other
                  graphics.

                * PREDITHERED: This is used in combination with
                  dithering performed outside of Gutenprint or with
                  printers that perform their own dithering.  It
                  assumes that the output is already dithered and
                  generates the appropriate drops based only on the
                  values provided.

        Linear Contrast Adjustment

                The standard contrast control does not adjust the
                black and white points of the output; black in the
                input becomes black in the output, for example.  The
                result is that if contrast is reduced below 1, the
                contrast in the highlights and shadows is actually
                increased to keep the same total tonal range.

                Gimp-Print 4.2 used a different kind of contrast
                control.  In Gimp-Print 4.2, reducing the contrast
                reduced the contrast throughout the tonal range,
                resulting in white being printed as a light gray and
                black as a dark gray (reducing the contrast all the
                way to zero resulted in a uniform gray).  If contrast
                was increased, the contrast was stretched until the
                output reached either black or white; anything lighter
                always printed as white and anything darker as black.

                Turning this control on selects the old Gimp-Print 4.2
                behavior.  This control is normally turned off.


Output Density Controls

    These controls adjust the amount of ink printed on the page.
    These controls may be used to darken a solid, pure black, or
    eliminate puddling (wet ink left on the paper that does not dry in
    the printer) if needed.  They may also be useful for adjusting the
    behavior of non-standard inks.  They should not be used to lighten
    or darken the print if the black level is correct.

    These controls are adjustments -- they adjust the amount of ink
    relative to the amount selected by the driver for the paper and
    resolution chosen.

        Density Value

                This control adjusts the total amount of ink used in
                all channels (ink colors).

        Black Density Value
        Blue Density Value
        Cyan Density Value
        Magenta Density Value
        Yellow Density Value
        Red Density Value

                These controls adjust the amount of ink used by each
                channel separately.  They may be used to correct the
                amount of ink if needed to strengthen or weaken
                particular colors (e. g. if yellow is too strong or
                too weak).  They should not be used to correct gray
                balance (to produce neutral gray) -- the gray balance
                controls described below should be used for that
                purpose.

        Ink Limit Value

                This control adjusts the maximum amount of ink that
                the driver will use to print with.  This may be used
                if you want to use large amounts of particular inks to
                achieve saturated dark colors, without using excessive
                ink overall that will result in ink puddling or
                spilling within the printer.  This control should be
                used only by people very experienced in inkjet
                printing.


Gray Balance Controls

    These controls adjust the gray balance by changing the amount of
    each color of ink used to produce gray.  For example, if gray
    prints somewhat greenish, it can be corrected by increasing the
    magenta balance.

        Magenta Balance Value
        Yellow Balance Value
        Cyan Balance Value


Output Gamma Controls

    These controls permit adjusting the gamma (exponent) of the
    transfer curves of the individual channels.  On most printers,
    using a linear ink scale (that is, the amount of ink is directly
    proportional to the input value) will produce very dark
    highlights, as even quite small amounts of ink produce very strong
    colors or gray.  Therefore, the driver uses less ink to produce
    lighter colors.  This does not affect the darkest tones.

    Setting these controls to larger values results in lighter
    highlights and midtones.  These controls are adjustments -- they
    adjust the gamma relative to the gamma chosen by the driver by
    multiplying them together.  For example, if the driver uses a
    gamma value of 2.0 for a particular printer, and you specify a
    gamma of 0.75, the actual gamma used to print will be 1.5.

        Composite Gamma Value

                This control adjusts the gamma of all available ink
                channels when printing in color.

        Black Gamma Value

                This control adjusts the gamma of the black channel
                when printing in grayscale.

        Magenta Gamma Value
        Yellow Gamma Value
        Cyan Gamma Value

                These controls adjust the gamma of individual channels
                when printing on printers that use cyan, magenta, and
                yellow inks (all inkjet printers use CMY inks).  These
                gamma values are multiplied by the composite gamma
                value and the gamma chosen by the driver.

                Note that the black gamma value is not used when
                printing in color.  That is because the amount of gray
                is computed after the gamma transformation has been
                applied to each channel, and the black channel is
                synthesized from this value.  The GCR Transition Value
                serves as a gamma value for the black channel.  In
                addition, there are no gamma values for the special
                channels for printers that offer additional inks (such
                as red and blue) for similar reasons.

        Red Gamma Value
        Green Gamma Value
        Blue Gamma Value

                These controls adjust the gamma of individual channels
                when printing on printers that use red, green, and
                blue inks (Postscript printers and many dye
                sublimation printers use red, green, and blue colors).
                These gamma values are multiplied by the composite
                gamma value and the gamma chosen by the driver.


Gray Generation Controls

    These controls adjust the conversion of gray into black ink and
    composite (CMY) components.  When printing in color, light grays
    are often printed using composite inks rather than black ink to
    reduce the speckling effect of dark black dots, while dark grays
    and black are usually printed using black ink to achieve a darker
    black.  With some ink and paper combinations it is necessary to
    use a mixture of black and composite components to achieve maximum
    density and in some cases to achieve neutral grays (some pigment
    black inks are actually brown).

    The effect of using too much or too little black ink varies.
    Typically if too much black ink is used light colors and grays
    will have noticeable speckling from the black drops, while if too
    little black ink is used the midtones and dark tones will be
    washed out and in some cases too much ink will be used leading to
    puddles on the page.  In some cases very large amounts of
    composite ink cause color shifts (darker grays are not neutral).
    Epson Premium Glossy Photo Paper seems to be particularly prone to
    this problem, particularly with dye inks.

    In general, lower-quality papers require more black ink (composite
    inks generally cannot create very dark tones), while higher
    quality papers require less black ink (the composite inks can
    create much darker grays, and the black dots appear much sharper).

    Setting these controls effectively requires a good understanding
    of gray generation and a fair amount of experimentation.  Normally
    it's only necessary to set the paper type correctly to get good
    results.

        GCR Lower Bound Value

                This control specifies the darkest shade of gray at
                which no black ink will be used (i. e. any lighter
                gray component will be printed using only composite
                inks).  Setting this control to zero means that some
                amount of black ink will always be used; setting it to
                1 means that no black ink will ever be used.

        GCR Upper Bound Value

                This control specifies the lightest shade of gray at
                which no composite CMY ink will be used (i. e. this
                level of gray and higher will be printed using only
                black ink).  This control should never be set any
                lower than the GCR Lower Bound Value.  Setting this
                control to zero means that only black ink is used to
                print any gray value; setting this control to a value
                greater than one means that some composite ink will be
                used even when printing black.  The upper limit for
                this control is 5 (in which case black will be printed
                with no more than 20% black ink).

                If you use an ink set requiring use of color inks to
                produce neutral grayscale, you should set the GCR
                Lower Bound Value to zero or a value very close to
                zero and the GCR Upper Bound Value should be greater
                than 1, along with a GCR Transition Value (below) of
                1.  This will ensure that the proportion of black and
                color inks will be close to constant throughout the
                gray range.  With this kind of inkset, it's often
                possible to produce cool or warm toned grayscale
                prints by selecting Desaturated color correction and
                adjusting the GCR Upper Bound Value appropriately.
                For example, if the black ink has a brown (warm) cast,
                increasing the GCR Upper Bound Value will yield a
                cooler tone (less black ink) while decreasing it will
                yield a warmer tone (more black ink).

        GCR Transition Value

                This control specifies the gamma of the GCR transition
                curve.  Setting this control to a smaller value
                results in less black ink being used in the lighter
                portion of the transition region.  This control is
                useful if the black ink is much darker than the
                composite inks in order to produce a smoother
                transition.

        GCR Curve

                This control (only available through the Print plugin
                for the GIMP or other Gutenprint-based applications
                that provide curve capability) allows you to specify
                the conversion curve from gray to black/composite
                precisely.  The horizontal axis of this curve
                represents the gray level (between 0, or no gray at
                all, and 1, or pure black); the vertical axis
                represents the fraction of gray that is converted to
                black (0 means only composite inks, and 1 means only
                black ink).


Output Linearization Curves

    These controls permit adjusting the transfer (linearization)
    curves of each channel precisely.  They are only available through
    the Print plugin for the GIMP or other Gutenprint-based
    applications that provide curve capability.  All of these controls
    are considered to be for very advanced use only.

        Black Curve
        Blue Curve
        Cyan Curve
        Magenta Curve
        Yellow Curve
        Red Curve
        Green Curve


Detailed Color Correction Curves

    These controls permit adjusting precise characteristics of color
    generation/correction.  They are only available through the Print
    plugin for the GIMP or other Gutenprint-based applications that
    provide curve capability.  All of these controls are considered to
    be for very advanced use only.

    The horizontal axis of all of these curves represents the hue of
    the output.  Hue is measured as an angle, where 0 and 360 degrees
    represent cyan (or red, if the output inks are RGB).
    Conventionally, these angles are represented as a number between 0
    and 6 (each full number in this scale represents 60 degrees).  The
    specific hue angles for CMY and RGB outputs are as follows:

             \                  Ink Type
        Angle \         RGB             CMY
        -----  \        ---             ---
           0    |       Red             Cyan
           1    |       Yellow          Blue
           2    |       Green           Magenta
           3    |       Cyan            Red
           4    |       Blue            Yellow
           5    |       Magenta         Green             
           6    |       Red             Cyan

        Hue Adjustment Curve
        Luminosity Adjustment Curve
        Saturation Adjustment Curve

                These controls adjust the color correction in High
                Accuracy, Bright Colors, and Correct Hue Only color
                correction modes.  These color correction modes work
                by adjusting the hue, saturation, and luminosity (HSL)
                of the output inks to achieve a more accurate color
                than the color created by simply converting the red,
                green, and blue inputs to cyan, magenta, and yellow
                (or red, green, and blue) inks.  Note that in this
                printing context luminosity represents darkness
                (amount of light subtracted) rather than brightness.

                The saturation and hue adjustments are first applied.
                The luminosity correction operates on only the color
                component of the output.  Before this correction is
                applied, any gray value is removed, and added back
                after the correction is completed.

                The vertical axis of the Hue Adjustment Curve
                represents an angular difference that is added to the
                base hue value to generate the desired output.  For
                example, if the blue output is purple (too close to
                magenta), adding a negative value to that range of the
                output will bring the blue value more toward cyan
                (less magenta).
                
                The vertical axis of the Saturation Adjustment Curve
                represents an amount by which the saturation is
                multiplied.  At any given hue point it may take on any
                value between 0 (eliminate all color saturation, which
                is equivalent to converting to pure gray) and 4
                (dramatically boost the saturation).  Therefore, this
                adjustment may be used to tone down excessively
                brilliant colors (e. g. if the reds are overly
                brilliant) or brighten up dull colors (e. g. if the
                greens are somewhat dull).  This control has no effect
                if Correct Hue Only is used.  If the saturation value
                is greater than 1, the effect differs depending upon
                whether High Accuracy or Bright Colors mode is
                selected: if Bright Colors is selected, the saturation
                is simply multiplied by the desired value and then set
                to 1 if it would exceed unity.  If High Accuracy mode
                is selected, the amount of saturation boost is
                decreased if the starting saturation is high.

                The vertical axis of the Luminosity Adjustment Curve
                represents an amount by which the luminosity is
                multiplied.  At any given hue point it may take on any
                value between 0 (remove the color component
                altogether) and 1 (leave it as is).  Therefore, the
                function of the Luminosity Adjustment Curve is to
                lighten excessively dark colors rather than to darken
                light colors.  This control has no effect if Correct
                Hue Only mode is used.

        Blue Map
        Cyan Map
        Magenta Map
        Yellow Map
        Red Map

                These curves control how the auxiliary red and blue
                inks are used on the Epson Stylus Photo R800, Stylus
                Photo R1800, and PictureMate family of printers.
                These printers use auxiliary inks to achieve more
                brilliance in the red and blue.  Other printers in the
                future may use other auxiliary channels, which will be
                made available in similar fashion.

                The vertical axis of each of these controls specifies
                the amount of each ink that should be used to print
                colors of that hue.  These curves are used only to
                generate color; any gray component is removed prior to
                the color generation and added back later.  For
                example, it is possible to specify that a certain
                shade of purple is printed using .2 red ink, .6
                magenta ink, and .5 blue ink (hypothetically).


Specialized Output Controls

    These controls are used to modify the output in very
    printer-specific ways.

        Gloss Level Value

                This control is provided on printers such as the Epson
                Stylus Photo R800 and R1800 that offer a special gloss
                enhancer to produce an even degree of gloss on glossy
                papers regardless of the amount of ink used.  On
                certain glossy papers, areas with high ink coverage
                are a lot glossier than areas with little ink coverage
                (highlights); the gloss enhancer is basically a
                transparent ink that increases the gloss of these
                areas.  This control specifies the desired total
                amount of ink to be printed, including both the normal
                color and black inks and the gloss enhancer.  If the
                amount of normal inks is less than this amount, gloss
                enhancer is used to increase the total amount of ink
                used.


Transition Controls

    These controls adjust the level at which light inks (such as the
    light cyan and magenta inks used on many "photo printers") are
    used in place of the dark inks.  The light inks are used to
    produce a smoother texture (less speckling); the light cyan
    droplets, for example, are individually much less visible than the
    normal dark cyan droplets.

    The ink substitution works by replacing a certain amount of ink by
    a mixture of the light and dark inks.  For example, the dark cyan
    ink may be about 3 times as dark as the light cyan ink, so in
    light areas the cyan may be replaced by 3 times as much light
    cyan.  However, this only works up to a certain point; beyond that
    point, adding more light ink does not significantly increase the
    darkness of the ink.  These transition values adjust the limits at
    which the ink substitution is done; the lower these limits are
    set, the lighter the output at which dark ink is introduced.
    Setting these values lower will generally yield more accurate
    midtone colors at the expense of more speckling in the light
    midtones and highlights.  Generally these values need to be lower
    on low-quality paper than on high quality glossy paper.

        Dark Yellow Transition Value
        Light Gray Transition Value
        Mid Gray Transition Value
        Dark Gray Transition Value
        Gray Transition Value
        Light Cyan Transition Value
        Light Magenta Transition Value
        Light Yellow Transition Value


Foomatic-only options

    This control is available only when using the Foomatic interface.
    It provides a collection of presets appropriate for various
    printing tasks.  It is similar in concept to (and provided the
    inspiration for) the Print Quality and Image Type options provided
    in Gutenprint.

        Printout Mode
