Indesign export black is opaque

[Eikichi]

Just like the tittle says. When I export using indesign PDF/X-1a 2001 preset the black is not black only opaque. What am I doing wrong. I've checked the rich black option and it is set correct. I've even added a huge black rectangle in front of the picture and set it to 100% K. In the adobe reader the rectangle is transparent. If I open the file in photoshop it is still transparent but when I open in ilustrator the black is just as it should be.

[Jeffrey_Smith]

Are you expecting the rectangle of 100% black to overprint the photo? It does, and to view the overprint, you need to turn on "Overprint Preview" in Indesign, or turn on "Simulate Overprint" in Acrobat.

[rob day]

In the adobe reader the rectangle is transparent. If I open the file in photoshop it is still transparent but when I open in ilustrator the black is just as it should be.

Offset printing inks are transparent and by default InDesign shows the transparency of the black ink when the object is set to overprint. The overprint value of default [Black] swatch is set in Preferences>Appearance of Black. Set it to knock out or use a swatch or color with any amount of CMY added.