"Photos with transparency" message when creating book PDF/uploading to Blurb

[MIKEGI]

When I create a PDF of a book project or upload the book to BLURB I get the message "Photos with transparency.  Some photos in the book have transparency. The transparent areas will show as opaque in your book." 

I have received this message n the past on a few photos in the book and could discover no transparency areas.

My most recent project has a number of DNG files created form photo merge (PANOs and HDRs); all these files were designated as "photos with transparency".

This seems to be a BUG in the BOOK Module. The PDF I created shows no "black" or "opaque' Areas.

Anyone have an explanation?

[Todd Shaner]

MIKEGI  wrote

My most recent project has a number of DNG files created form photo merge (PANOs and HDRs); all these files were designated as "photos with transparency".

When creating Panoramas with LR Photomerge there is generally some transparency showing at the edges of the image. Unless you use Boundry Warp 100 setting the DNG will have transparent edges that show as white. The same can happen when creating HDRs with 'Auto Align' checked due to camera movement. I checked both LR Photomerge DNG file types and they contain an EXIF data SubIFD1 PhotometricInterpretation tag  of 'Transparency Mask.' This is most likely what's triggering the warning message and of no consequence if you cropped-out those areas. If you didn't crop-out the transparency areas they will simply show as white.