File Size

[StainX]

Hi!

If i open a pic with lets say 300dpi and save the .afphoto file... it has like 40MB.
So i change to 10dpi and save again.... the file size won't change?

Win10 Pro x64
Afphoto 1.9.2.1035

[Alfred]

DPI (or more correctly here, PPI) specifies how closely packed the pixels should be on output. So an image which is 600 pixels square will be 60 inches (i.e. 5 feet) square if printed at 10 DPI but only 2 inches square if printed at 300 DPI. Since there’s no difference in the number of pixels, there’s no reason for the file size to change.

[StainX]

I know dots per inch should represent the amount of information in a "Picture", so less Information, should usually still end up in less file size...
It works as it should when i export a jpg out of it.

OK, i found out why that is happening, if i work with an Image layer (imported from stock panel) it keeps this image information intact no matter what document setting.
If i rasterize the Image layer after import, it works as expected, which makes sense. Stupid me 

[Komatös]

The file size depends mainly on the number of pixels and the colour profile.

A 16-bit RGB image (one layer) is (without compression) about 1.5 times larger than an 8-bit RGB and 2.5 times smaller than a 32-bit RGB image. 

[Alfred]

1 hour ago, StainX said:

It works as it should when i export a jpg out of it.

JPEG is a lossy format, even at ‘100%’ quality (i.e. minimum compression) but exporting to non-lossy image file formats will also discard information, leading to smaller file sizes.