code: public void simplifyColorspace() {
          if (additional == null)
              return;
          PdfArray value = additional.getAsArray(PdfName.COLORSPACE);
          if (value == null)
              return;
          PdfObject cs = simplifyColorspace(value);
          PdfObject newValue;
          if (cs.isName())
              newValue = cs;
          else {
              newValue = value;
              PdfName first = value.getAsName(0);
              if (PdfName.INDEXED.equals(first)) {
                  if (value.size() >= 2) {
                      PdfArray second = value.getAsArray(1);
                      if (second != null) {
                          value.set(1, simplifyColorspace(second));
                      }
                  }
              }
          }
          additional.put(PdfName.COLORSPACE, newValue);
      }
docs: Replaces CalRGB and CalGray colorspaces with DeviceRGB and DeviceGray.