DeviceInfo ColorDepth setting doesn't work

Question

I try to save my localreport in image format. But I discover that DeviceInfo's ColorDepth setting doesn't work.

 string mime, encoding, fileNameExtension;
 string[] streams;
 Warning[] warnings;
 byte[] bytes = report.Render("IMAGE", @"<DeviceInfo><OutputFormat>TIFF</OutputFormat><ColorDepth>8</ColorDepth><StartPage>0</StartPage></DeviceInfo>", out mime, out encoding, out fileNameExtension, out streams, out warnings);

 FileStream fs = new FileStream("C:\\imgRep.tiff", FileMode.OpenOrCreate);
 fs.Write(bytes, 0, bytes.Length);
 fs.Close();

Independently of ColorDepth value, the result is .tiff file with ColorDepth = 24.

Does anyone know how to fix this bug?

I convert this bytes into another PixelFormat:

Bitmap orig = new Bitmap(new MemoryStream(bytes));
Bitmap clone = orig.Clone(new Rectangle(0, 0, orig.Width, orig.Height), PixelFormat.Format8bppIndexed);
clone.Save(@"c:\imgPixelF.tiff", ImageFormat.Tiff);

But I'm not sure it is a good decision..

Answer 1

According to SQL Server Books Online TIFF-images you render from reports will always be saved as 24-bit in current versions.

For this release of SQL Server, the value of this setting is ignored, and the TIFF image is always rendered as 24-bit.

Since ReportViewer/LocalReport is just a clientside use of SQL Server Reporting Services you will be bound by the same limitation there.

It is a bit curious though that they say that ColorDepth is only supported for TIFF-images, and in the next sentence they say that the setting is ignored anyway in the current version and has been so since SQL Server 2005.