Loss of Cover Image Quality During docx to ePUB Conversion

Malcolm JW · 04-19-2021, 12:26 PM

I'm using Calibre to convert a Word docx file to an ePub for 'wide' distribution of my ebook. It's a novel, mostly text with some map images in an appendix.

Now, the map images in the appendix come through fine, but for some reason the cover image suffers a subtle loss of quality when I read the ePub on my Kindle Previewer. The sharpness of the text in the cover is lost, leading to a slightly 'out-of-focus' effect.

It's serious enough that it is not acceptable for retail distribution as it stands.

I upload the main body of the novel as the docx file and then upload the cover image separately as a jpeg in the Edit Metadata screen.

Can anyone suggest a solution?

retiredbiker · 04-19-2021, 02:16 PM

[QUOTE=Malcolm JW;4114037]...and then upload the cover image separately as a jpeg in the Edit Metadata screen.QUOTE]

If you load the cover by Edit Metadata, how do you get it into the actual book file? Polish? If so is there any chance that you have the Polish set to do image compression? It will only do lossless compression, but still you might see a difference.

If that is not the case, I'd open the epub in the Editor and look at the cover image as it is in the book file: is it exactly the same file size and dimension as the original image? If not (for whatever reason) you can right-click on the cover image in the Editor and "replace file with..." to bring in the original image.

If it is indeed the original image, how is it coded in the cover html file (probably called titlepage.xhtml)? Polish will put it in with an svg wrapper, which should work fine.

If all that is correct...a viewer problem?

Malcolm JW · 04-19-2021, 02:19 PM

I found the fix!

On the Convert page there is a little box labelled "Use cover from source file". When this box is ticked, Calibre loads the cover image from the high-res file in the meta data. Then the cover image comes through nice and sharp.

04-19-2021, 12:26 PM	#1
Malcolm JW Junior Member Posts: 2 Karma: 10 Join Date: Apr 2021 Device: none	Loss of Cover Image Quality During docx to ePUB Conversion I'm using Calibre to convert a Word docx file to an ePub for 'wide' distribution of my ebook. It's a novel, mostly text with some map images in an appendix. Now, the map images in the appendix come through fine, but for some reason the cover image suffers a subtle loss of quality when I read the ePub on my Kindle Previewer. The sharpness of the text in the cover is lost, leading to a slightly 'out-of-focus' effect. It's serious enough that it is not acceptable for retail distribution as it stands. I upload the main body of the novel as the docx file and then upload the cover image separately as a jpeg in the Edit Metadata screen. Can anyone suggest a solution?

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04-19-2021, 02:16 PM	#2
retiredbiker Evangelist Posts: 450 Karma: 3886916 Join Date: May 2013 Location: Ontario, Canada Device: Kindle KB, Oasis, Pop_Os!, Kobo Forma	[QUOTE=Malcolm JW;4114037]...and then upload the cover image separately as a jpeg in the Edit Metadata screen.QUOTE] If you load the cover by Edit Metadata, how do you get it into the actual book file? Polish? If so is there any chance that you have the Polish set to do image compression? It will only do lossless compression, but still you might see a difference. If that is not the case, I'd open the epub in the Editor and look at the cover image as it is in the book file: is it exactly the same file size and dimension as the original image? If not (for whatever reason) you can right-click on the cover image in the Editor and "replace file with..." to bring in the original image. If it is indeed the original image, how is it coded in the cover html file (probably called titlepage.xhtml)? Polish will put it in with an svg wrapper, which should work fine. If all that is correct...a viewer problem?

04-19-2021, 02:19 PM	#3
Malcolm JW Junior Member Posts: 2 Karma: 10 Join Date: Apr 2021 Device: none	I found the fix! On the Convert page there is a little box labelled "Use cover from source file". When this box is ticked, Calibre loads the cover image from the high-res file in the meta data. Then the cover image comes through nice and sharp.

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