using (var api = OcrApi.Create())
    {
        api.Init(Languages.English);
        using (var renderer = OcrPdfRenderer.Create(@"d:\0\multipage", @"tessdata"))
        {
            renderer.BeginDocument("Title");
            var image = Image.FromFile(@"d:\0\multipage.tif");
            int pageCnt = image.GetFrameCount(FrameDimension.Page);

            for (int index = 0; index < pageCnt; index++)
            {
                image.SelectActiveFrame(FrameDimension.Page, index);
                using (var bmp = new Bitmap(image.Width, image.Height))
                {
                    using (var g = Graphics.FromImage(bmp))
                    {
                        g.DrawImage(image, 0, 0, image.Width, image.Height);
                    }
                    using (var pix = OcrPix.FromBitmap(bmp))
                    {
                        api.InputName = @"multipage.tif";
                        api.InputImage = pix;
                        api.SetImage(pix);
                        api.SourceResolution = 95;
                        api.Recognize();

                        var b = renderer.AddImage(api);
                    }
                }
            }
            renderer.EndDocument();
        }
    }
}