Recent 'Preview' bug for transparent images in PDFs

Targets macOS
1

I dont know if anyone else has encountered this but I suspect there may have been some recent change to Preview on MacOS

A PDF generated using DynaPDFMBS which contains a bitmap having a transparent background
Displays perfectly on screen
But when printed is a solid black blob

I already have a workaround (no transparency) , but I’m getting reports ‘all at once’ about code of mine that has not changed for years.

2

Remember something like this 10 years ago (or more), it was something to do with image format fr the bitmap and certain Epson printer drivers.

I recall we worked around it by drawing the picture into 32-Bit RGB SRGB colorspace image and then sending that to the print routine, which created the PDF.