I often import (jpeg, pdf, etc.) black and white line drawings, sketches and graphics and was using the transparency tool selecting "darken" from the second pull down. It would take my b/w line drawings and quickly change to clean black line image with no background, that feature appears to have gone away. When I select line drawing transparencies I created using that feature, it now just lists "darken(old)".

Is there another way to quickly convert b/w graphics to transparency with no background?

Thanks for any and all suggestions