"Multiply" effect in ePub

Forum|Forum|6 years ago
January 16, 2020
16 replies
2269 views

I have an ID doc with images set to "multiply" with an identical clipped image set to normal on top, all on top of a colored background. Creating a PDF and printing, image produces as expected. When exporting ID 2020 to ePub, the "multiply" setting is not respected and I'm getting the white background of the image. Any ideas on how to solve, or is this a limit of ePub? As you can see, also having font issues, but the developers tell me then can hard code that.

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Mike Witherell

Community Expert

My recommendation would be to use PSD but stop using clipping paths. Rather, make Layer Masks.

In testing your document, I see the InDesign document set to (Edit > Transparency Blend Space ) CMYK but it should be RGB? My experience with groups and epub is that InDesign 2023 v18 is able to handle the conversion to PNG and the alt text correctly.

Mike Witherell

rayek.elfin

Legend

Sorry Mike, but I think you are misunderstanding the issues related to epub export and blending/transparency effects here. This has nothing to do with clipping paths, layer masks, or blend space.

Mike Witherell

Community Expert

Old PostScript techniques and wrong base document blend space is definitely a factor. But in this thread the question shifted a bit from the OP. Your advice about grouping was sound and epub issues related to grouped objects has been improved in v18. The essence of my advice is to simplify the approach. That was also Bob's essential advice.

Mike Witherell

rayek.elfin

Legend

To amend the answers given by Bob: blend modes are not directly supported by epubs, but will work in an epub when the objects (the foreground object(s) with the blend mode set and the background object(s) that is/are affected by that blend mode) are grouped, and the Object Export Options are changed as follows for that group:

The PPI should be set to 72ppi when using an iPad Retina document: the group will then be rasterized to the exact required resolution (do not use 150 or 300ppi, which will needlessly generate a much too high resolution image far exceeding the actual resolution of an ipad's screen).

M

MOD indy-go girl

Known Participant

I have the same problem and tried your grouping method, @rayek.elfin following all your settings. It didn't work. Maybe there's something else I should be doing? Here are the packaged indesign files, if that's helpful.