using System;

using System.Drawing;

​

public class Program

{

    public static void Main()

    {

        var c = System.Drawing.ColorTranslator.FromHtml("#FFB854");

        Console.WriteLine("Lighter: " + ChangeColorBrightness(c, (float)0.75));

        Console.WriteLine("Darker: " + ChangeColorBrightness(c, (float)-0.4));

    }

​

    public static Color ChangeColorBrightness(Color color, float correctionFactor)

    {

        float red = (float)color.R;

        float green = (float)color.G;

        float blue = (float)color.B;

        if (correctionFactor < 0)

        {

            correctionFactor = 1 + correctionFactor;

            red *= correctionFactor;

            green *= correctionFactor;

            blue *= correctionFactor;

        }

        else

        {

            red = (255 - red) * correctionFactor + red;

            green = (255 - green) * correctionFactor + green;

            blue = (255 - blue) * correctionFactor + blue;

        }

​

        return Color.FromArgb(color.A, (int)red, (int)green, (int)blue);

    }

}