How do you deal with boxy screentoon effect on your display with high resolution images?

[remunramu]

Im sure you guys already aware of this screentoon effect. This normally happens when you try to view high res image on a lower resolution screen, I think this is basically forced the dots to shrink even smaller and thus creating this sort of effect. A non screentoon image will not have this sort effect.

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As you can see from the image, the original image is 4256x3056 while my device's display is 2560x1600. If I view it in portrait it will that boxy effect, but it will be fine if I view it in landscape.
So how do we call this effect and what the best way to deal with it?

 

[Noobmaster69__]

@remunramu
try compressed images
if that does nothing just use landscape for that picture

 

[alexsilener]

High resolution images are resampled to display on low res screens. So the image quality will therefore depend on the resampling algorithm being used. Check what is being done by your display program.
For instance on CDisplayEx, you can change it from nearest neighbour to Lanczos, which improves results drastically. For both upscaling and downscaling.
(Also if you're using windows, make sure no resizing is being done by it as well. Or whichever OS)

 

[remunramu]

@ Noobmaster69__ That would take a work and may lose some quality in the process, so I still prefer the original. The landscape is only work with the joined pages, the normal page which is in portrait will look that boxy effect instead, its a vice versa.

@alexsilener On PC that images are look fine with windows photo viewer, my problem is in android device.

 

[alexsilener]

doesn't matter which OS. I only mentioned windows as an example. Rest is still the same. You'll have to check the settings of the application you're using for displaying those images. Look for 'resampling/resizing algorithms' or something along those lines. Otherwise use a different application which allows you to control this.

also on that losing quality in the process thing. By viewing a higher res image on a lower res screen, you're automatically 'losing' quality. It's how displays work. Wouldn't worry about that too much.

 

[fizhsmile]

If you use android device I recommend you using Kuro Reader. They have a down scaling feature, I tried the manga you use above and it worked. I have Tab S5e with the same 2560x1600 resolution as your device. As alexsilener said, no matter what you do resampling does affect quality, but the differences are not something you can complain about. For the most part, they are still look fine.
Here is some result resampled to 1500px within the app.

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Edit: added spoiler (big pic)

 

[BzzBzz]

It's called moire effect or moire pattern. It depends on the zoom ratio of halftone image. If it's "integer" ratio (x1/2, x1/4, etc.) it will not happen or can be very small (in case of zoom ratio close to "integer" like x1/2.05). If zoom ratio let's say x3/5 it can be very heavy. You can do nothing with this. Blame the laws of physics

 

[remunramu]

@fizhsmile It looks better. Thanks Im gonna try the app.

@BzzBzz I see, so that what is called, really nice info. I don't understand why they apply this haftone anyway, I read it on net its because manga is disposable media and publishers want to save production cost saving some inks by doing this. Its a weird reason, is that really the reason why halftone exist?

 

[BzzBzz]

> I don't understand why they apply this haftone anyway

It's actually pretty simple. Halftone method is based on basic optical illusion - when dots are small enough then human eye interpret it as smooth tones. This indeed allows to save some resources (read "money").
Regarding usage of halftones in digital manga... Preprint makets for physical manga are produced digitally, but if you prepare halftone version for physical print there's no reason to do same work twice and redo "digital" version with solid colors.

TL;DR: blame the publishers for greed. There's no other reasons.