C# Magick.Net conversion from pdf to tiff is low quality depth 1, how to set depth to 2

Question

I'm converting pdf's to tiff, however the quality of the produced tiff is very bad. How can I control the quality outcome? I compared the output quality of the same file through another process and it was better... the difference between the the two files were the depth (file properties) one was 1 and the other was 2

Added a code sample to show what i am trying... anyone with suggestions or a better way to do this? am rather new to the product. App is a .Net core console app, using Magick.NET-Q16-AnyCPU and Ghostscript 9.26

I've tried to change the density in my code sample but it just results in much larger file with very little improvement in quality

        var readSettings = new MagickReadSettings
        {
            Density = new Density(300,300),
            Compression = CompressionMethod.Group4,
            BackgroundColor = MagickColor.FromRgb(255, 255, 255),
            Format = MagickFormat.Pdf
        };

        var fi = new FileInfo("C:\\temp\\abc.pdf");

        using (var tiff = new MagickImageCollection(fi.FullName, readSettings))
        {

            // Add all the pages of the pdf file to the collection
            var tiff_filename = fi.DirectoryName + "\\" + fi.Name + ".tif";
            tiff.Write(tiff_filename);
        }