ColorScaleExample.cs

using OfficeOpenXml;
using System.Drawing;
using OfficeOpenXml.ConditionalFormatting;
using OfficeOpenXml.Drawing;

namespace EPPlusSamples.ConditionalFormatting
{
    internal class ColorScaleExample
    {
        public static void Run(ExcelPackage pck)
        {
            var sheet = pck.Workbook.Worksheets.Add("ColorScales");

            sheet.Cells["A1:B20"].Formula = "ROW()";

            var twoScale = sheet.ConditionalFormatting.AddTwoColorScale("A1:A20");
            var threeScale = sheet.ConditionalFormatting.AddThreeColorScale("B1:B20");

            twoScale.LowValue.Color = Color.CadetBlue;
            twoScale.HighValue.Color = ColorTranslator.FromHtml("#FF63BE7B");

            threeScale.LowValue.Color = Color.DarkRed;
            threeScale.MiddleValue.Color = Color.Orange;
            threeScale.HighValue.Color = Color.ForestGreen;
            //ColorSettings attribute allow you to use tint
            threeScale.HighValue.ColorSettings.Tint = 0.80;

            //It can also be used for alternative ways to set color. Note: Only last applied colorsetting matters.
            //Except for Tint which works with all.

            //threeScale.LowValue.ColorSettings.Theme = eThemeSchemeColor.Accent3;
            //threeScale.MiddleValue.ColorSettings.Auto = true;
            //threeScale.HighValue.ColorSettings.Index = 3;

            threeScale.MiddleValue.Type = eExcelConditionalFormattingValueObjectType.Percentile;
            threeScale.MiddleValue.Value = 50;

            sheet.Cells.AutoFitColumns();
        }
    }
}