Imagemagick depth convert

Question

Having an imgage in.png. Now do the next:

$ convert in.png -strip out.tiff     #convert to tiff
$ convert out.tiff -strip out.png    #and back
$ cmp in.png out.png
$#no output - the images has no difference - theyre same

$ identify in.png out.png
in.png PNG 300x300 300x300+0+0 16-bit sRGB 1.65KB 0.000u 0:00.000
out.png[1] PNG 300x300 300x300+0+0 16-bit sRGB 1.65KB 0.000u 0:00.000

now trying this via eps. So:

$ convert in.png -strip out2.eps        #convert to eps
$ convert out2.eps -strip out2.png      #back

and the images are different.

$ identify in.png out.png out2.png
in.png PNG 300x300 300x300+0+0 16-bit sRGB 1.65KB 0.000u 0:00.000
out.png[1] PNG 300x300 300x300+0+0 16-bit sRGB 1.65KB 0.000u 0:00.000
out2.png[2] PNG 300x300 300x300+0+0 8-bit sRGB 4c 321B 0.000u 0:00.009

As you can see, the conversion eps -> png creates 8-bit png.

Curiosity plus - the EPS is 16 bit!

$ identify out2.eps 
out2.eps PS 300x300 300x300+0+0 16-bit sRGB 1.42KB 0.000u 0:00.000

Questions:

• why the eps->png conversion changes the bit-depth?
• how to convert from eps to png to get 16-bit png? (as from tiff).

EDIT

Tested @Rachel recommendation:

$ convert out2.eps -depth 16 out3.png
$ identify out3.png 
out3.png PNG 300x300 300x300+0+0 8-bit sRGB 4c 518B 0.000u 0:00.000

8 bit again.

My ImageMagick version:

$ convert --version
Version: ImageMagick 6.8.9-1 Q16 x86_64 2014-06-01 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2014 ImageMagick Studio LLC
Features: DPC Modules
Delegates: bzlib djvu fftw fontconfig freetype gslib gvc jng jp2 jpeg lcms ltdl lzma pangocairo png ps tiff webp wmf x xml zlib

If anyone want test, here is my test image:

FINAL

So, @Mark Setchell and @Rachel Gallen's recommendation are good. @Marks command works, so the key is PNG48.

$ convert out2.eps -depth 16 PNG48:out7.png
$ identify out7.png
out7.png PNG 300x300 300x300+0+0 16-bit sRGB 1.86KB 0.000u 0:00.000

Finally 16-bit png. What I will ask it in another question, why the next:

$ mogrify -strip out7.png
$ identify out7.png 
out7.png PNG 300x300 300x300+0+0 8-bit sRGB 4c 321B 0.000u 0:00.000

8 bit again. And the -strip should remove only metadata and should not change the image itself.

Answer 1

I think you need something along these lines to get 16-bit PNGs

convert a.png -depth 16 PNG48:b.png