HD? (Not a major issue just an inquiry.)

[bbmak622]

Is there an option to make a hd cbz? My old scans came out in hd but my new ones are now blocky and grainy.

[Cortys]

Hm. That sounds odd.

What exactly do you mean by "blocky and grainy"? Are comics, that once were backuped in HD, blocky and grainy now as well or are only new purchases affected?

There is no HD option or something similar, since the extension simply stores exactly what it gets from Comixology and there is no known way to influence the image quality in the web reader.

[bbmak622]

Both new and already purchased books that were once hd. They used to look like the standard comixology comics but now it's like the quality really took a drop. I'm gonna try another pc and see if that works.

[Cortys]

Any news on this?

[bbmak622]

Sorry for not responding sooner, btw, but it appears as its comixology's general site. Even reading straight from the site seems to be a very standard quality. I tried it on a smaller monitor and that made it appear better than on a large scale monitor. Thanks for following up!

[Cortys]

No problem.

So quality probably cannot be improved atm.

I'll leave this open as a reminder anyway. Maybe the situation changes in the future.

[stevenmh]

I've noticed something similar. My comic reader is a Samsung Galaxy Tab S 10.5 with 2560x1600 resolution. If I open a downloaded and locally stored comic in the Comixology app and then open a scan of the same comic in a CBR reader, they look identical at first glance at full page viewing. If I zoom in, though, the version on Comixology is clearly higher resolution and retains its quality when enlarged. If I open the same comic on my laptop with 1920x1080 resolution and zoom in, I see the same issue with lower resolution when zoomed in.

I guess Comixology is using a lower resolution when "streaming" a comic through the web reader than what it gives you when you download a comic to local storage, and that is the resolution the scanner has to work with.

[sgbeal]

@stevenmh the backup utility uses the resolution which the backend feeds it. It has, to the best of my knowledge, no influence over the resolution - it takes what it gets from Comixology. It is potentially possible that Comixology serves different resolutions depending on any number of hypothetical factors (e.g. user agent string).

[stevenmh]

Something odd is going on. I noticed my recent scans appear soft. This is using the same 2.3.2 installation on the same machine as I've been using all along. So I took a scan of an issue that I previously scanned back in May, and sure enough, the more recent scan isn't as sharp as the previous scan. Then I took a screen shot of the comic open in the Comixology web broswer, and that gave a better image, so it's not a limitation of resolution being presented by the Comixology web browser. Finally I went into the extension options and chose single JPEGs in lieu of CBZ, and the single JPEGs are even better than the screen shot. So if I select single JPEGs it comes out fine, if I choose CBZ it comes out fuzzy. It's like it's downrezzing and/or applying softening to the JPEGs to create the CBZ. But it wasn't doing that before, and nothing on the PC has changed. I don't get it.

[Cortys]

@stevenmh That's indeed odd. I could not reproduce it though.

Since the CBZ implementation simply zips exactly the same JPGs that are downloaded directly when the single image option is active, I currently have no idea how this could possibly happen.

Could you post the name of an example comic and a page number that illustrates the issue you described clearly?

In addition to that a screenshot of your extension options, your OS and your Chrome version would be helpful, just to make sure I'm as close to your setup as possible.

Lastly, to have something to compare my results against, could you post the exact resolutions of a blurry version of a page vs a non blurry version of a page and possibly even a side by side comparison of an image section that prominently shows the difference? Please only post a small section to prevent a copyright strike (this has happened before).

[stevenmh]

The comic is Marvel Darth Vader #1.

I previously backed up all of my books back in the May timeframe when I made my last post. That was on an Asus N550J with 1080p screen running Windows 8. I don't know the version of Chrome at the time, but the extension version was and still is 2.3.2.

I recently purchased a Surface Pro 4 and wanted to see if the higher screen resolution would in any way improve the scanning. I scanned Darth Vader #1 on it and felt like it wasn't as sharp. I thought it might be because I'm used to reading on a Galaxy Tab S 10.5, and assumed I was getting the same scan resolution on a larger screen, but decided to check anyway.

So I got the Asus back out and opened my old scan from May and the new scan from this weekend side by side in Free CBZ Reader and could tell that the old scan was sharper. I deleted the new scan and rescanned the comic on the Asus since that's what was used for the old scan. The only change I can recall making on the Asus since May is updating from Windows 8 to 8.1. I assume there have been some other Windows updates in the interim. Chrome may or may not have updated itself since then. The version I'm running now which was used for the newer scans in the attachments is 54.0.2840.99m.

First attachment is the old scan vs new scan side by side in Free CBZ Reader. Old scan is on the left. It has more grain but is sharper. When viewing the entire page the grain isn't noticeable, but the increase in sharpness is. The new scan reminds me of when you edit a RAW file and go overboard on the noise reduction. Detail gets scrubbed out with the grain and it looks soft.

Second attachment is when I tried setting the extension to scan to JPEG. It's not entirely apples to apples since it's two different pieces of software, but I got them sized as close as possible. You can see the JPEG has more pop. Letters in the upper left are clearly sharper. If that were the only comparison available I'd say it's possible that the source material is the same and the photo viewer is applying sharpening and the CBZ viewer is not. But the first attachment clearly shows a deterioration in image quality since May that I'm not able to explain given the same hardware and essentially the same software.

Third attachment is the extension options. These are what I have always used, except it was previously CBZ instead of JPG.

Fortunately I have the Arc Welder extension working on the Surface Pro with the Comixology App and it looks great. I still use my Samsung 10.5 for dedicated reading sessions. The backups are only in the event I wake up one day and my digital library in the cloud is gone for some reason, which I don't expect to happen. But when making archives it's always nice to make the best quality you can.

Please let me know if you need any other info.

Thanks,
Steve

[stevenmh]

Any thoughts?

[Cortys]

@stevenmh Thanks for your detailed response!

I've now looked into this. As expected the extension downloads what the web reader shows pixel-perfectly (apart from the expected minor derivations caused by the JPEG encoding).

So the easiest explanation for your problem probably is, that cmxly started serving a slightly different version of the comic you mentioned some time ago. Maybe that's all there is to this, which would mean that there is nothing you and I could do about it.

However just to make sure there isn't anything else that causes the problem, I've also backed up the Darth Vader #1 comic and tried to compare it to the scans you posted. Since those were scaled up using some non-NN interpolation method, this did not really work though.

To make sure we both get the same scans, could you verify that your new scan matches this one I've created today?

This could be done by laying your scan and mine on top of each other and looking for pixel differences (I've zipped the scan to make sure GitHub does not make any further changes to the image). If our scans match, I'm afraid the problem is not fixable and you are lucky, that you backed up the comic at the right time.

Thanks for your help!

[philbetts]

Briefly looking into it, the app version for phones and tablets saves much higher res versions than they're streaming to the browser app. How are you with Android? :p