<sect3 id="editor-color-bw">

    <title>Black and White Conversion Filters</title>

    <para>
        Black &amp; White photography has always been fascinating in its abstraction capability.
        With the advent of digital photography, B&amp;W has almost become a desktop activity, 
        as color images can be easily converted on the computer into black and white, 
        even providing a set of vintage film roll profiles.
        This filter is also able to simulates traditional infrared film material.
    </para>

    <sect4>
        <title>The Legacy Black and White Films Emulation</title>
        <anchor id="blackandwhitetool.anchor"/>

        <para>
            &digikam; comes with a couple of black &amp; white filters that you can use on your photographs. 
            Under the <menuchoice><guimenuitem>Color</guimenuitem><guimenuitem>Black &amp; White...</guimenuitem></menuchoice> menu 
            you will find classic black &amp; white chemical toning used in analog photography. 
            The controls come on four drop-down items: <emphasis>Film, Lens Filters, Tone</emphasis> and <emphasis>Lightness</emphasis> as shown on the screenshot below. 
            Film, filters and color toning can be applied independently of each other (on top of each other). 
            The filters actually influence the RGB channel mixing, whereas the toning purely adds a uniform monochromatic tint to the black &amp; white photograph. 
            In the lightness tab you will find a tonal adjustment tool (like curve adjust), a contrast tool and an over-exposure indicator to improve the b&amp;w rendering.
        </para>

        <example>

            <title>The Black &amp; White Filter tool in Action</title>
            <screenshot>
                <screeninfo>The B&amp;W Filter tool in Action</screeninfo>
                <!-- TODO: need a new screenshot -->
                <mediaobject><imageobject><imagedata fileref="&path;editor-bwfilter.png" format="PNG" /> </imageobject></mediaobject>
            </screenshot>

        </example>

        <para>The table below shows in more detail the effect of all filters and tints.</para>

        <informaltable><tgroup cols="2">

        <thead><row>
            <entry>Preview</entry><entry>Photographic Film Emulation</entry>
        </row></thead>
        <tbody>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwred.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                <para>Specific settings to emulate a number of famous black &amp; white photographic films are available:</para>
                <para>Generic</para>
                <para>Agfa 200X, Agfa Pan 25, Agfa Pan 100, Agfa Pan 400</para>
                <para>Ilford Delta 100, Ilford Delta 400, Ilford Delta 400 Pro 3200, Ilford FP4 Plus, Ilford HP5 Plus, Ilford PanF Plus, Ilford XP2 Super, Ilford SPX 200 (Infrared), Ilford SPX 400 (Infrared), Ilford SPX 800 (Infrared)</para>
                <para>Kodak Tmax 100, Kodak Tmax 400, Kodak TriX, Kodak HIE (Infrared)</para>
                </entry>
            </row>
        </tbody>
        </tgroup></informaltable>

        <informaltable><tgroup cols="2">
        <thead><row>
            <entry>Preview</entry>
            <entry>Lens Filter Type</entry>
        </row></thead>
        <tbody>
            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-original.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Original color image taken in New Zealand landscapes.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bw.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                No Lens Filter: simulate black &amp; white neutral film exposure.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwgreen.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

            <entry>
                Green Filter: simulates black &amp; white film exposure with green lens filter. This comes good with all scenic images, especially suited for portraits taken against the sky (similar to 004 Cokin(tm) Green filter).
            </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bworange.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Orange Filter: simulates black &amp; white film exposure with an orange lens filter. This will enhance landscapes, marine scenes and aerial photography (similar to 002 Cokin(tm) Orange filter).
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwred.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Red Filter: simulates black &amp; white film exposure with red lens filter. Creates dramatic sky effects and can simulate moonlight scenes in daytime (similar to 003 Cokin(tm) Red filter).
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwyellow.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Yellow Filter: simulates black &amp; white film exposure with yellow lens filter. Most natural tonal correction, improves contrast. Ideal for landscapes (similar to 001 Cokin(tm) Yellow filter).
                </entry>
            </row>
            <!-- TODO: 
            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwyellowgreen.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Yellow-Green Filter: TODO.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-bwblue.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Blue Filter: TODO.
                </entry>
            </row> -->

        </tbody>

        </tgroup></informaltable>

        <informaltable><tgroup cols="2">

        <thead><row>
            <entry>Preview</entry> <entry>Hue (Color Tint)</entry>
        </row></thead>

        <tbody>
            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-sepia.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Sepia Filter: gives a warm highlight and mid-tone while adding a bit of coolness to the shadows - very similar to the process of bleaching a print and re-developing in a sepia toner (typical for your grandmothers photographs). Similar to 005 Cokin(tm) Sepia filter.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-brown.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Brown Filter: similar to Sepia Tone filter, but less pronounced.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-cold.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Cold Filter: start subtle and replicate printing on a cold tone black &amp; white paper such as a bromide enlarging paper.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-selenium.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Selenium Filter: effect that replicates traditional selenium chemical toning done in the darkroom.
                </entry>
            </row>

            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-platinium.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Platinum Filter: effect that replicates traditional platinum chemical toning done in the darkroom.
                </entry>
            </row>
            <!-- TODO:
            <row>
                <entry>
                <inlinemediaobject><imageobject><imagedata fileref="&path;editor-convert-green.png" format="PNG" /> </imageobject></inlinemediaobject>
                </entry>

                <entry>
                Green Filter: TODO.
                </entry>
            </row> -->

        </tbody>

        </tgroup></informaltable>

    </sect4>

    <sect4>
        <title>Simulate Infrared Film</title>
        <anchor id="infraredtool.anchor"/>

        <para>
            Simulating classical infrared film material (the effect is rendered in black and white) 
            is an interesting alienation effect that is even stronger and more dramatic than pure black and white 
            conversion. Contrast and an abstract touch are improved, which can underpin the expression 
            of the photographer as an artist.

            It is like taking an image in black and white with a red filter on the camera lense. 
            Areas which reflect little red light, &eg; the sky, will show as low density, dark areas. 
            Areas which are excellent reflectors of red light, &eg; most green foliage, will be high 
            density areas. And snow landscapes are really dramatic.
        </para>

        <para>
            <!-- TODO: https://www.gimp.org/news/2015/01/22/gimpguruorg-rip/ - without link -->
            The algorithm is based on the method of the 'Simulate Infrared Film' tutorial of the GimpGuru.org 
            web site available at <ulink url="http://www.gimpguru.org/Tutorials/SimulatedInfrared">this url</ulink>.
            The filter tries to reproduce the famous Ilford(tm) SFX infrared film series. 
            This film has a sensitivity range of 200-800 ISO.
        </para>

        <para>
            The left part of the dialog window lets you select the region to be shown in the preview section. 
            Move the red rectangle with the mouse around to show the effect on different parts of the image.
        </para>

        <para>
            The lower part provides the two controls, Film Grain and ISO sensitivity. 
            Check the <guilabel>Add Film Grain</guilabel> box if you want to simulate the 
            grainy texture of a high sensitivity film. The ISO-level slider modifies the amount of 
            filmgrain added and the predominance of green color (chlorophyll in nature) 
            in the conversion mixer. Green pastures will become white as snow! Try it out.
        </para>

        <note><para>
            Because the filter mixes color channels to reproduce infrared film (with emphasis on green channel), 
            one can not simulate infrared effect from black and white original photograph, 
            since the color information is missing.
        </para></note>

        <para>
            This is an example of the infrared film effect applied to a color image taken in New Zealand's landscapes. The original image is (1) and the converted image is (2). The film sensitivity used to simulate the infrared film is ISO-400. Higher ISO values will create a kind of aura in the highlights.
        </para>

        <para><inlinemediaobject><imageobject> 
            <imagedata fileref="&path;editor-infrared-preview.png" format="PNG" /> </imageobject>
            <textobject><phrase>The Infrared filter in Action</phrase></textobject></inlinemediaobject>
        </para>

    </sect4>

</sect3>

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