USAGE

DESCRIPTION:  Converts digital film negatives (TIFF files) to positive images,
              allowing basic image editing. These utilities are used:

              - GNU Parallel: Use all CPU cores for maximum speed
              - ImageMagick:  Negative inversion, B/W grayscaling,
                              contrast enhancements, resizing,
                              ZIP or JPEG compression

USAGE:        Batch mode: Process all TIFF files in current directory:
              $ positive -a [OPTIONS]
              $ positive --all [OPTIONS]

              Process one or more TIFF file(s):
              $ positive [OPTIONS] FILE [other FILE(s)]

OPTIONS:
-a, --all     Use batch mode, process any TIFF file in working directory.

--debug       Switch on really verbous debug mode

-d, --desaturate
              Desaturate colors, recommended for B/W neagtives.
              Bonus: The TIFF will be converted to 16 bit Grayscale,
              saving up to 60% in file size; The image will have
              linear gamma 1.0 ICC profile applied (Gray-elle-V4-g10.icc).

-f, --flipflop direction
              Mirror the image vertically or horizontally.
              Possible values are:

              flip     - mirror upside-down
              flop     - mirror in the horizontal direction
                         This is the way to go when your negatives
                         have been digitalized on their emulsion (back) side.
              flipflop - Both directions

-g, --gamma value
              Gamma correction value to apply.
              It is highly recommended to use this parameter with -n.

              Values are up to your taste and the negative density!
              Examples for typical values are:

              auto - Calculated gamma based on image mean values.
                     Recommended for ‘real life images’.
              1.0  - No Gamma for linear TIFFs.
                     This is the default value if omitted.
              1.8  - Moderate darkening, resulting in light images
              2.2  - Well-known software standard;
                     This is what common photo software would apply.
              3.6  - Smooth tones, not too light
              4.4  - Still mellow, not too contrasty
              5.0  - Still usable results with uncropped negatives

-j, --jpg quality
              Convert to JPG, using this JPG quality.
                0: Do not convert. Same as omitting this parameter.
               92: overall best quality.
              100: nearly useless best quality.

-n, --normalize
              Normalize: Stretch histogram to reach black and white points.
              Recommended for most images.

-o, --output path
              Output directory; Default is current working dir.

-r, --resize pixel
              Resize larger side to this pixel length, preserving aspect ratio.

-s, --sigmoidal value
              Sigmoidal contrast value around 50% middle-gray.
              Increases the contrast without saturating highlights or shadows.
              Quoted from ImageMagick docs: "3 is typical and 20 is a lot."
              Disabled if omitted.

-v, --verbous
              Turn on verbous mode.

HOMEPAGE:     <https://github.com/tomkyle/negatives-positive>

LICENSE:      CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>