File Size for 4K image?

[Anonymous]

Hello! I want to create a painting for a contest with a 4k resolution. (Mostly because I also want to use it as a wallpaper when I'm done for my 4k monitor) My first question is: after I finish the painting, because it is high resolution, will the .png file be over 10mb? Or not? The contest requires files smaller than that. 

Also, when I adjust the canvas size, what numbers would I need to put for the width and height for it to be 4k?

Thank you! Any help is appreciated!

[patrick.muenster]

Hi, officially 4K is defined a 4096 × 2160 pixels. But you can reduce the height for widescreen setup. The most 4k devices today are using UHD 3840 x 2160. So I would recommend you to use this resolution. 

The file size of a .png depends on the lossless compression algorithm. There are a few  out there in Affinity Photo, Photoshop or similar software. Furthermore by using some of this compressions tools, the file size depends on the details of you painting. I don't know what sketchbook is using but it is definitly bigger than with Affinity Photo.
The size of the file I've tested increased to 5,21MB (Sketchbook Desktop) from 2,29MB (Affinity Photo).

But before you thing about something like that, you should start painting first. My comic style pictures usually take "only" 4MB in 4K. 

For using the image all wallpaper you should use jpg format.

Hope this helps a bit.

[patrick.muenster]

Oh, by the way,
the size file size shown in your screenshot is the memory size Sketchbook needs per layer to work on the document. So the number of layers is limited by your RAM. Saved as png, it will be around 5MB again.

[Anonymous]

So, if I make it a jpeg, it could be a smaller size? Also is 3840 the height, or width? 

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@patrick.muenster wrote:

Hi, officially 4K is defined a 4096 × 2160 pixels. But you can reduce the height for widescreen setup. The most 4k devices today are using UHD 3840 x 2160. So I would recommend you to use this resolution. 

The file size of a .png depends on the lossless compression algorithm. There are a few  out there in Affinity Photo, Photoshop or similar software. Furthermore by using some of this compressions tools, the file size depends on the details of you painting. I don't know what sketchbook is using but it is definitly bigger than with Affinity Photo.
The size of the file I've tested increased to 5,21MB (Sketchbook Desktop) from 2,29MB (Affinity Photo).

But before you thing about something like that, you should start painting first. My comic style pictures usually take "only" 4MB in 4K. 

For using the image all wallpaper you should use jpg format.

Hope this helps a bit.

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[patrick.muenster]

Yes, that's right!
Using Jpg (JPEG) will decrease the filesize by keeping the resolution and is a common format for publishing any graphic content.

But keep in mind that jpg is not a lossless compression, so choose a high quality (maybe between 70 and 90) for avoiding artefacts. And jpg does not support transparency of course!

[vupt.cpa]

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