Calibre reducing cover resolution.

[dvpzoey]

Hello everyone,

I am very much new to the magnificent "Calibre".

Recently I am facing a problem where Calibre is reducing the book (in epub) cover resolution.

original res: 1686 x 2760
reduced by Calibre: 1331 x 2200

What do I do?

[kovidgoyal]

Preferences->Tweaks->maximum cover width/height

[stumped]

so you have a device that can actually display epub cover at 1686 x 2760 ?
impressive, if true. What is it ?

[Quoth]

Maybe an app on a big Tablet?

Device: Kindle on Android

Or a smaller tablet / phone with hiDPI aka Retina screen.

[JSWolf]

Originally Posted by stumped

so you have a device that can actually display epub cover at 1686 x 2760 ?
impressive, if true. What is it ?

That's not the issue. I want the original res of the cover kept. I do reduce it to 1600 lines.But I only want it reduced once.

[stumped]

Originally Posted by Quoth

Maybe an app on a big Tablet?

Or a smaller tablet / phone with hiDPI aka Retina screen.

It would have to be a very big tablet, or require incredible eyesight to actually see the difference

[dvpzoey]

Originally Posted by stumped

so you have a device that can actually display epub cover at 1686 x 2760 ?
impressive, if true. What is it ?

No.

I am a starter in ebooks, ereaders, related softwares.

Recently I was facing a problem with books having low resolution covers. Such books when opened don't display cover but a blank thumbnail, which I personally don't like.

I am bit choosy over book covers. To change book covers I use Calibre.

Confusion arose when I read somewhere that min book cover resolution is 1400 x 2100.

I need advice over the best option for cover size and resolution and over jpeg/tiff/png file formats.

[pdurrant]

Originally Posted by dvpzoey

No.

I am a starter in ebooks, ereaders, related softwares.

Recently I was facing a problem with books having low resolution covers. Such books when opened don't display cover but a blank thumbnail, which I personally don't like.

I am bit choosy over book covers. To change book covers I use Calibre.

Confusion arose when I read somewhere that min book cover resolution is 1400 x 2100.

I need advice over the best option for cover size and resolution and over jpeg/tiff/png file formats.

You can have 1400x2100 covers if you like, but be aware the calibre has a default maximum size less than that. You can change this, as Kovid said, in the calibre preferences. (Preferences->Tweaks->maximum cover width/height)

Please don't ask the same question in more than one place at the same time. Your other two posts have been deleted.

[pdurrant]

Originally Posted by dvpzoey

Recently I was facing a problem with books having low resolution covers. Such books when opened don't display cover but a blank thumbnail, which I personally don't like.

That's not going to be because of a 'low resolution' cover, but of the way amazon processes side-loaded books.

[dvpzoey]

Originally Posted by pdurrant

You can have 1400x2100 covers if you like, but be aware the calibre has a default maximum size less than that. You can change this, as Kovid said, in the calibre preferences. (Preferences->Tweaks->maximum cover width/height)

Please don't ask the same question in more than one place at the same time. Your other two posts have been deleted.

My Calibre Preferences show:
maximum cover size = (1650, 2200)

I read that Kindle Paperwhite has a screen res. of 1448 x 1078 pixels (6" display).

Please answer these 2 queries:
1. What is optimal cover size for this device-resolution (6"/7" Kindle)?
2. File format: jpg/tiff/png?

Certainly, big cover sizes are not helpful, e-book size will increase unnecessarily.

sorry for the double post. I got confused first time I posted because I didn't see my post. I didn't it was due for moderation check.

[pdurrant]

Optimal? That's not really a question with an answer. Optimal for what?

Unless you intend to produce covers that are tailored to a particular device (which I would discourage), a sufficiently large number of pixels, and a sufficiently small amount of compression.

IMO, over 2,000 pixels high and a moderate JPEG compression would be optimal. It will look good on anything. (Although low contrast colour images can look poor on greyscale devices no matter what their resolution.)

JPEG for the file format. It usually gives the best compromise between size and number of pixels, so long as you don't set the compression too high which can introduce obvious artifacts.

If, however, you are generating the image yourself, the original ought to always be saved as TIFF or PNG (lossless).

[stumped]

Well JPG, aka jpeg, is a lossy format. Someone obsessed with image quality should not be using it for covers They should be insisting on lossless.!

It's the visual equivalent of the MP3 vs Cd quality Vs insanely hi Def audio format debates

Most people cannot see / hear the difference between a well engineered lossy format and a guaranteed lossless one but they convince themselves they can. And pay handsomely for the premium product.

I don't believe that anyone with a 10 inch screen can distinguish a 1600 pixel wide image from a 3200 pixel one,, and most , myself included, can't pick out 1600 from 1200. Or distinguish a decent JPG from a lossless image

[JSWolf]

Originally Posted by stumped

Well JPG, aka jpeg, is a lossy format. Someone obsessed with image quality should not be using it for covers They should be insisting on lossless.!

It's the visual equivalent of the MP3 vs Cd quality Vs insanely hi Def audio format debates

Most people cannot see / hear the difference between a well engineered lossy format and a guaranteed lossless one but they convince themselves they can. And pay handsomely for the premium product.

I don't believe that anyone with a 10 inch screen can distinguish a 1600 pixel wide image from a 3200 pixel one,, and most , myself included, can't pick out 1600 from 1200. Or distinguish a decent JPG from a lossless image

I agree that most wont see the different between JPG and PNG. But I disagree with the won't hear between lossy and lossless. I'll hear the difference much more then i'll see the difference.

[dvpzoey]

Originally Posted by pdurrant

Optimal? That's not really a question with an answer. Optimal for what?
.

Ok, let me rephrase my question.

Let's take example of Kindle Paperwhite. It has a screen res. of 1448 x 1078 pixels (6" display).

For this device, cover res. should be at least 1448 x 1078 pixels.

I am getting a lot of info over this post. Thank you everyone: @Kovid, @pdurrant, @stumped, @JSWolf.

On a side note: how do I enter username in my post. does @user_name work here? Or do enter names manually.

[stumped]

Originally Posted by JSWolf

I agree that most wont see the different between JPG and PNG. But I disagree with the won't hear between lossy and lossless. I'll hear the difference much more then i'll see the difference.

I spent a lot of time both listening and searching out well constructed blind listening test results
the evidence is pretty compelling that most of the people who claim to hear the difference, actually can't. Those few with actual golden ears ( typically recording engineers & the like ) , have trained themselves on what to listen out for in order to spot the difference e.g. sound of cymbals decaying..

I cannot distinguish MP3 at 320 / spotify premium rate OGG, from 16 bit CD, or from 24 bit HD streams e.g. from Qobuz. But that's with equipment costing £several hundred, not with equipment costing £several thousands. There's a point at which I'd rather spend more on the music than on the playback equipment
I am not sure if being able to, or believing you can, hear the difference is actually a blessing or a curse. Arguably it makes a music hobby much more expensive
e.g. An extreme audiophile will spend more on an interconnect cable than I would spend on an entire system, and will be utterly convinced that it sounds better.

same with pictures , paintings- the more quality conscious you become the more it costs . I do find it amusing when some £Millions art work is redefined as fake after fooling everyone for many many years. Its the same picture, it looks just like it did when it was considered genuine - all that's changed is the provenance ( & the resale value)