[GeoffR]

I have a small number of books with colour images that look good on a colour display but very bad on a greyscale display, so I want to make custom greyscale images that only display on greyscale devices, and continue to display the colour images on colour-capable devices.

I made an ePub book that checks whether the display is colour-capable, and can select the appropriate image. It uses @media queries and Adobe XPGT conditionals so should work on both of Kobo's readers, ePub and KePub, and It also seems to work okay in Calibre. But I noticed that on my Glo the KePub reader is reporting that it has a colour display.

(Edit: I should add that the firmware version is 4.8.11073)

Maybe I don't understand how the @media queries work? Or maybe it is a problem with the KePub reader? This is the query code I used:

div.display-iff-color-unknown { display: block; }
div.display-iff-color { display: none; }
div.display-iff-not-color { display: none; }

@media (color) {
    div.display-iff-color-unknown { display: none; }
    div.display-iff-color { display: block; }
    div.display-iff-not-color { display: none; }
}

@media (max-color: 0) {
    div.display-iff-color-unknown { display: none; }
    div.display-iff-not-color { display: block; }
    div.display-iff-color { display: none; }
}

and the HTML to show the result:

  <div class="display-iff-color-unknown">
    <p>Color: Unknown</p>
  </div>
  <div class="display-iff-color">
    <p>Color: Yes</p>
  </div>
  <div class="display-iff-not-color">
    <p>Color: No</p>
  </div>

Attached is a simple ePub example (Edit: Updated to fix ePub orientation result, didn't affect KePub color result.)