Convert PDF to tiff + Merge PDF problem with color

I have following 2 methods:

1. Convert PDF to Tiff

string loadfile = @"D:\Data\PDF_Farbe\PDF091.pdf";
            string savefile = @"D:\Data\newTEST\PDF091.tiff";
            string saveMultifiles = @"D:\Data\newTEST\sectest{0}.tiff";

            RasterCodecs.Startup();
            RasterCodecs codecs = new RasterCodecs();
         
            LeadTools_RasterSupport_Unlock();
            RasterImage image;

            CodecsImageInfo imgIngfo = codecs.GetInformation(loadfile, true);
            int count = imgIngfo.TotalPages;

            for (int i = 1; i <= count; i++)
            {
                image = codecs.Load(loadfile, 32, CodecsLoadByteOrder.Rgb, i, i);
                codecs.Save(image, string.Format(saveMultifiles, i), RasterImageFormat.Tif, 1, 1, 1, 1, CodecsSavePageMode.Append);
            }

2. Merge PDFs

List<string> pdfFileList = new List<string>();

            pdfFileList.Add(@"D:\Data\PDF_Farbe\PDF091.pdf");
            pdfFileList.Add(@"D:\Data\PDF_Farbe\PDF091_1.pdf");
            pdfFileList.Add(@"D:\Data\PDF_Farbe\PDF091_2.pdf");
            pdfFileList.Add(@"D:\Data\PDF_Farbe\PDF091_3.pdf");
            pdfFileList.Add(@"D:\Data\PDF_Farbe\PDF091_4.pdf");

            foreach (string str in pdfFileList)
            {
                image = codecs.Load(str);
                codecs.Save(image, @"D:\Data\newTEST\testPDF.PDF", RasterImageFormat.RasPdfG4, 1, 1, image.PageCount, 1, CodecsSavePageMode.Append); 
            }

but the output is gray, i want it in color. How can i do this in both?

If you mean that the result file (After Merge) is gray, I noticed that your code is saving the result with "RasPdfG4" compression  (or no compression at all) and 1-BPP. One-bit images cannot have more than 2 colors, in your case black and white. The gray shades you see are probably the effect of dithering or paint scaling. Try to save it as RasPdfLzw or RasPdfJpeg411 and set the Bits per pixel to 24.
If the problem didn't solved , isolate the problem in small working project(not your full application) and send it to me. Also, provide sample images that shows the problem.

Note: Make sure to put the files in a ZIP or RAR file to ensure our server delivers them correctly and send us the uploaded file name.

Ok problem solved. Thank you.