Import a jpg to 2.10.8

[une]

GIMP Version: 2.8.14
Operating System: Windows
GIMP Experience: Intermediate Level

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In the new 2.10.8 there is the possibility in the setting to choose ” use 32 bit floating point precision when importing files”.
But what happens when you import a 8 bit jpg file?
For instance if you import a black and white jpg with 256 greys, what happens inside gimp when it will be opened as 32 bit?
Are there still only 256 greys or ....
What happens when I edit the imported 8 bit file with 32 bit?
I have thought about this but I do not understand ....
Hope that someone can explain for me
Une

[racer-x]

The 32 bit floating point precision is mainly for importing RAW or high bit-depth TIFF and DNG files to maintain high details. If you import an 8 bit image like a jpg, it will be up-sampled using dithering. Information will be created that wasn't there before. No real reason to use high bit-depth editing on an 8 bit image.

[rich2005]

An 8 bit RGB jpeg is 8 R + 8 G + 8 B = 24 bits A greyscale 8 bits = 1 byte (bad description 256 possible values), as stated only has 256 shades of grey. Any blurring or maybe a gradient and banding becomes a problem with visible divisions between shades.

Upping to a higher precision and linear will give better results. Would I bother setting in Preferences, not really. Treat each image individually.

For RGB jpegs even Ad*be recommend upping to 16 bit for editing.