Colors Dulling When Exporting from InDesign to EPUB

[John Paizs]

Hi. I made a graphic (e-)novel that I want to publish on AppleBooks and Kindle. In exporting from InDesign to Epub, something is happening to the colours. I've attached two screen captures. The 1st shows how the artwork appears in InDesign (which is also how it appears in the linked file in Photoshop; it's correct). The 2nd shows how it appears in EPub. You can see how the colors have dulled down. I've tried everything I can think of in InDesgn to fix the problem, but no luck. Can someone please help?

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[James Gifford—NitroPress]

EPUB == HTML/web. Any graphics you include must be, basicallly, web-optimized.

So if your source files are not web-RGB JPG or PNG, the conversion is going to change the colors one way or the other.

What format are your source images in, and what's your workflow for the export? What Object export options are you using?

Also know that some of the result depends on the reader (as does so much with EPUB). It's not as wide an issue as some other format and presentation ones, but you might try viewing your export on more vanilla readers like Thorium or Calibre, just to see if the color issues are the same as in the (somewhat off-standard) Apple reader.

[John Paizs]

Thank you, James, for your reply! My source images are tiffs, in RGB mode. As for the object export options, they are "EPUB and HTML", if that makes sense.

And thanks for the heads up re the different readers. I'll try them once I get my export to look right in my Books app, on my Mac, which is what I've been using to check my epubs.

So what I'll try now is converting my source files to PNG. In my document setup in InDesign, does it matter if my "Intent" is "Print" or "Web"?

Thank you so much again!

[John Paizs]

The workflow for the Export is "Format: PNG; Resolution: 300". And I'm rasterizing the 1st page. That's all I'm setting there.

[Robert at ID-Tasker]

300 is rather overkill? 

[John Paizs]

It is? I was not aware. What is the usual then?

[Robert at ID-Tasker]

72 is pretty much standard. 

300 is for print. 

[John Paizs]

Thanks for letting me know. I'll give 72 a try.

This is my first e-book, so a bit of a learning curve.

[James Gifford—NitroPress]

There are a lot of hurdles. And fixed-page layout, which is more or less required for 'picture page' books like graphics novels, can be difficult to get optimal results from.

[James Gifford—NitroPress]

Actually, no. Kindle prefers 300 (which is excessive for most pictures-in-a-book, IMHO), and most standard EPUBs use 150. For a full-page picture such as a graphic novel, 300 is on the luxurious side but not unsusual or excessive for decent resolution on a variety of reader/apps.

I'd stay with 300 unless 150 shows perfectly adequate resolution and image quality — keeping in mind that you can't really get "art grade" reproduction and a tiny bit of improvement may not be worth 2X file size/bloat.

[James Gifford—NitroPress]

Image color shouldn't shift that much from TIFF source, but there is much less control of color conversion/export to EPUB than there is for, say, PDF.

First, try export to JPEG instead of PNG, just to see if it improves the color (and check, while you're at it, if things like text and details are fine at both 300 and 150). That alone may be the solution.

Second, convert a couple of your source files to 300ppi PNG and see if export, first to PNG, and second with "Use Existing Image..." checked in the Object pane of the export menu.

TIFF can be a difficult format to convert for anything but highly managed PDF export.

[John Paizs]

Thank you so much again, James, for all this terrific advice. Very very much appreciated. I'll do what you say, will try both 300 and 150 and see what the resiults are. Will also try jpeg vs png. Given that the art conversion is of course critical for this (any) graphic novel, I'd much rather err on the side of a larger file size, as long as it's still workable of course once it's up at the stores.

[John Paizs]

I misunderstood your JPEG suggestion. Yes, I did try exporting in JPEG, using both baseline and progressive options. But, same faded results. So I'll just stick to converting my TIFFS to PNGs for the sources, and then when I export in InDesign, I'll try both the JPEG and PNG options. I'll post the results here tomorrow.

[John Paizs]

Picking up from yesterday, I changed all my source files to PNG from TIFF. And unfortunately I'm still getting duller colours in my exports to EPUB from InDesign. I exported using both the PNG and the JPEG workflows, with the same result. I also thought I would try a PDF, and the opposite problem occured – the colours are too saturated. (See attached screen captures). If there's anything else you could suggest, James (or anyone), that would be awesome. I don't know what else to try...

[James Gifford—NitroPress]

I'm tempted to say it's a viewer issue. If you are checking "Use original graphic" then the export process should do exactly that: write the original source file into the EPUB composite. If the nominally unchanged file looks different in the reader... it's the reader.

A hard-core way to tell would be to take apart the EPUB and check. EPUBs are just a ZIP file, so you can open them by either renaming them to .ZIP or using an archive tool that recognizes EPUB as an archive format (7-Zip is one).

In the archive file, you'll basically find a packaged website. In one of the two primary folders is a subfolder named \images. Copy all the files from there to a new folder, and open them in any viewer or gallery app. That will tell you if it's InDesign making the images "brighter," or the export or the EPUB reader making them duller.

Overall, RGB images should pass through the process with no real change in vibrance etc., even if they are reprocessed for size. This all sounds very much like a CMYK-to-RGB color alteration, but you sound like you're image-savvy enough to understand that issue. Are you sure your TIFFs weren't saved as CMYK (for print, for example) or a poorly chosen RGB color profile?

[John Paizs]

I also took a screen cap of the EPUB on my iPad to compare, and used the eye dropper tool in Photoshop to read the numbers of those colours and comapre them with those on the screen cap that I took of the EPUB on my desktop computer, and the numbers are the same. So that's two readers that are giving me the same colours. As for my TIFFs, they definitely weren't saved as CMYKs. The colour profiles on the TIFFs as well as the PNGs are sRGB IEC61966-2.1, which I think is standard for RGB? I'll "unzip" the EPUB as you suggest and see what I find. Thanks...!

[John Paizs]

I mangaed to unzip the EPUB with an application called Unzip One. I found the image folder, and copied the file corresponding to the one I've been using to compare to my desktop, and opened it. It's colours are the same as what I was getting from my EPUB screen captures. The same RGB values, which are dulled down... When you ask if I'm checking "use original graphic," where is that found exactly? Because when I go to export, I get a dialogue box named "EPUB - Fixed Layout Export Options". But nowhere do I see there "Use Original Graphic."

[James Gifford—NitroPress]

So the export process is absolutely changing the images? I am not surprised.

And *headsmack* I forgot to review the FXL export settings before my suggestion — I forget there are some significant differences. In this case, there is almost none of reflowable's control over image management, including the ability to do a straight export of the original image.

All of which is why —

• I don't work with fixed-page layout EPUB;
• I don't recommend anyone use FXL except for a very narrow range of applications  — but unfortunately graphic novels are one of them;
• One of FXL's biggest faults is the limited ability to control and tweak the export;
• and, in the end, InDesign is just not a good platform to do FXL exports except for the simplest, least demanding projects. That is, if what you get is good enough, good enough, but don't expect to be able to get anything else.

This may be one of the VERY rare cases where there may be no solution but the community, largely freeware EPUB tools can build a suitable file for your needs. It's a messy, complicated, badly-documented and even more poorly 'advised' world, and the best advice I can give you is make sure you are dealing with current apps, tools, procedures and requirements, and filter all tutorials, advice and how-to through a thick layer of BS and ego remover. (Far too many out there advising the newbs worked out one process, a decade ago, and vociferously attack all other tools, approaches, advice, etc.)

Sigil seems to be the highly-regarded, all-in-one tool for EPUB work at the erector-set/build-a-bear level. However, I think it's only available for Windows. I have no other recommendations for an FXL EPUB workflow.

As what little of an answer I can give: I have no idea what InDesign is doing to images, colors, etc. — or why. But that's FXL, which is as easy as driving off a high cliff.

[John Paizs]

Thank you, James, for the very informed reply!  And thank you for the advice re the "solutions" to be found in the world of largely freeware EPUB tools. I'll be sure to proceed with caution if I end up going that route! I'll also check Sigil just to make sure they don't have a Mac version. There is also Affinity Publisher, which is a fairly inexpensive app and I think generally gets good reviews (I noticed a lot of Affinty tutorials on Skillshare). But yes, why InDesign would not provide the same level of image control for Fixed Page Layout exports is totally beyond me. Anyway... thank you so much again for the generosity of your time and of your expertise. Very very much apprecited!!! And if I ever get this worked out (hopefully I will) I'll post here what the workaround was. Have a great day!

[James Gifford—NitroPress]

Yeah, sorry to have nothing but no-workee answers on this. I might poke around to see if I can figure out what ID is doing under the hood, but it's purely an intellectual exercise and, overall, more reasons to avoid FXL and put little faith in ID's FXL export.

Unless something has changed in the last year, Affinity doesn't export to EPUB. It's frustrating that there are so few good paths from source material to acceptable EPUB without relying on sticks and sharp rocks workflows.

It may not be quite the right direction, but KDP has two tools that produce FXL results for Kindle, and it may be possible to get from their native file formats to an EPUB that can be repurposed for Apple. (What I think of KDP's tools etc. is even less than most community tools and processes, so let's just leave it at that.)

[John Paizs]

Thank you ... and no worries! I learned a lot about InDesign as it relates to EPUBs in this process, which has been most valuable. Re Affinity not exporting to EPUB, I'll check to see if something has changed possibly in the last year as to that. Have nothing to lose at this point. And I sure don't want to lose the vibrancy of my colours in my Graphic (E-)Novel, which I worked so hard on, so I'll leave no "sharp rock" unturned in my quest to get this figured out! I'll also look into KDP.... (that's how commited I am...!) Thank you!!!

[James Gifford—NitroPress]

No worries. There are a lot of different "worlds" when it comes to EPUB, mostly for somewhat annoying reasons (lack of an enforced standard, for one, and a standard that is nearly 15 years old now, for another). You have to pick and choose which approach works best for you.

The absolute takeaway here, which is valuable knowledge to have acquired, is that InDesign's FXL export is doing something unwanted and undocumented to image files. It doesn't really change the overall map of things, and may not matter to some users, but that it's happening at all is well worth having learned — so thank you! Check back with your observations on other solutions.

[Laura Brady]

Make sure that the images place in the InDesign file are RGB. InDesign will convert CMYK to RGB, but you might want to manage that yourself so that the colour doesn't go haywire. If it's still happening, you could open the EPUB and replace the images with versions that you are happy with. 

One caveat: you cannot control how the colour displays on device. It will look great on an iPad probably, and less great on a colour Kindle or Kindle Fire. 

[James Gifford—NitroPress]

We've established that the source images are RGB, and substituted source file types to make sure it's not a weird TIFF thing. Readers on two systems (and platforms) show the dulling, as do images extracted from the EPUB. Clearly, InDesign is doing something to the image values, but what or why is as opaque as the black box that is its FXL export process. (The OP seems to have very good grasp of image files and color models and such, so I don't think it's an understanding/communication issue.)

ID is simply not a useful tool for FXL creation except to the lowest, least demanding standard. Which, IMHO, is on a level with it not making good paper airplanes, either. 🙂

[John Paizs]

Thank you, Laura! The images I'm linking to in InDesign are definitely RGB. Opening the EPUB and replacing the images with correct ones colour-wise is a very interesting suggestion. I managed to "unzip" my EPUB to see if the images in there are the problem (they are, they're dulled down). So you're saying that I could turn the unzipped EPUB back into an EPUB after I've swapped the images??