<div>
var mymap = L.map('mapid').setView([20.5937, 78.9629], 5);

        L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token=pk.eyJ1IjoibWFwYm94IiwiYSI6ImNpejY4NXVycTA2emYycXBndHRqcmZ3N3gifQ.rJcFIG214AriISLbB6B5aw', {
            maxZoom: 18,
            attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
                '<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
                'Imagery © <a href="http://mapbox.com">Mapbox</a>',
            id: 'mapbox.streets'
        }).addTo(mymap);

        var fogDepth = plotty.addColorScale("mycolorscale", ["#00ff00", "#0000ff", "#ff0000"], [0, 0.5, 1]);;

        plotty.addColorScale("test", ["#00ff00", "#0000ff", "#ff0000"], [0, 0.5, 1]);


        var fogDepth = L.leafletGeotiff(
            url = 'FOG.tif',
            options = {
                band: 0,
                displayMin: 0,
                displayMax: 45,
                name: 'Fog Depth',
                colorScale: 'rainbow',
                clampLow: false,
                clampHigh: true,
                //vector:true,
                // arrowSize: 20,
            }
        ).addTo(mymap);
</div>

I have added a rainbow color scale to the GeoTIFF file with band=0 min value 0 and max value 45, the tiff file in the grey scale of band =1 how can I change to color scale to rainbow?
with the above code, I am getting this output, and its in scale between 0-1: