[digiKam-users] BMP Vs PGN

[gene heskett]

On 11/25/22 10:53, Alberto Guardia wrote:
> Hi,
> 
> I shot in RAW (actually Fuji's RAF) and get standard 26.1 Mb files.
> 
> After processing them I get respectively :
> 
> PNG 79,8 Mb  ==> 3 times !!
> 
> BMP 48,8 Mb  ==> 1,87 times !
> 
> JPEG 14,2 ==> 0.54 times.
> 
> 
> Do Png files really need to be so large or is there something wrong in 
> my settings?
> 
> Tks
> 
> Alberto
> 
> - Digikam's  "ShowPhoto" editor (version 5.6.0)
> 
> 
> 
> .
I have not explored digikams methods as I got into the habit of doing 
that recompression in gimp, as it allows you to see the effect of the 
compression in the preview window when re-exporting to .jpg's if 
selected. So I always select that and pull the compression slider to 
around 15%, then I inspect the preview for moire effects in the colors. 
Then adjust the slider till it looks natural again. Busy images will be 
over half a gig, but digitally generated images which don't have the 
lighting gradients real images have, can usually be smunched down to 
200k or so. If digikam has borrowed that, you should be able to see the 
compression effects and adjust it for pleasing results at pretty high 
compression ratios.

Digitally generated png's are the compression winners here, a quite 
complex box project to house the all new electronics of a tronxy-400-pro 
printer I'm rebuilding, as spit out by OpenSCAD, is only 16 kilobytes.

Cheers, Gene Heskett.
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