I'm trying to make tiled pyramidal tiffs from master tiff images using Java (JAI 1.1.3 + imageIO). The problem is: I NEED to make tiff files compressed in jpeg with RGB photometric interpretation and no matter what I try, the image still faces YCbCr photometric interpretation.

Note: if I change compression type (eg. LZW or Deflate) I can get RGB colorspace but, as I said, I need jpeg compression.

Except this detail the tiled PTiff I create it's ok, so I think it's better to focus the attention on simple compression step (uncompressed tiff --> jpeg tiff)

this may be a basic example (removing any check to make it more readable)

    // reading MASTER
    BufferedImage img = ImageIO.read(uncompressedTiff);     

    ImageOutputStream ios=null;
    ImageWriter writer=null;
    ios = ImageIO.createImageOutputStream(outFile);

    Iterator <ImageWriter> writers = ImageIO.getImageWritersByFormatName("tiff");
    writer = writers.next();

    // saving and compression params
    writer.setOutput(ios);
    ImageWriteParam param = writer.getDefaultWriteParam();
    param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT); 
    param.setCompressionType("JPEG"); 
    param.setCompressionQuality(0.8f);
    param.setTilingMode(ImageWriteParam.MODE_EXPLICIT);
    param.setTiling(256, 256, 0, 0);

    IIOMetadata metadata = getWriteMD(writer, param);

    // writing
    writer.write(metadata, new IIOImage(img, null, metadata), param);

in getWriteMD method:

   ....
   TIFFTag photoInterp = base.getTag(BaselineTIFFTagSet.TAG_PHOTOMETRIC_INTERPRETATION);
   TIFFField fieldPhotoInter = new TIFFField(photoInterp, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_RGB);
   ....

here is the full version of getWriteMD()