Opening 16 bit tiff files

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Re: Opening 16 bit tiff files

Post by xnview »

Lynx_TWO wrote: Sun Jun 28, 2020 3:58 pm Apparently, NConvert doesn't use 16-bit either - I just tried setting up a .bat file to convert 16-bit PNG and it converts to 8 bits per channel.

nconvert.exe -crop 0 67 720 405 -o %% -clevel 9 *.png
you need to use -org_depth
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Re: Opening 16 bit tiff files

Post by marsie321 »

I have a similar problem, that the file is not recognized correctly. It is a multi-page 16-bit grey tiff but nconvert idetects it as 16Bit (with or without -org_depth). Can I set the input format somehow and prevent nconvert from any conversion?
I would like to extract all pages and save the tiffs as 16Bit without any conversion to 8-Bit.
Otherwise I am very happy with nconvert, it extracts all pages and writes all exif/meta data! :P

identify ./DJI_0018.TIFF
./DJI_0018.TIFF[0] TIFF 640x512 640x512+0+0 16-bit Grayscale Gray 2.16959GiB 2.830u 0:10.921
./DJI_0018.TIFF[1] TIFF 640x512 640x512+0+0 16-bit Grayscale Gray 2.850u 0:10.928

nconvert -v -i -ctype grey -org_depth -in tiff ./DJI_0018.TIFF
** NCONVERT v7.39 (c) 1991-2019 Pierre-E Gougelet (Feb 25 2020/13:19:45) **
Version for Linux x86 (X11) (All rights reserved)
A TIFF (RGB) was recognized : ./DJI_0018.TIFF
Width:640 Height:512 with 256 colors
Nplanes : 1 Bitscount : 8
Bytes Per Plane : 640
xdpi : 0 ydpi : 0
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Re: Opening 16 bit tiff files

Post by oakside »

xnview wrote: Fri Nov 22, 2019 11:18 am currently only NConvert can load/write in 16bits
Regarding this 8 bit processing. Can this be explained a bit more?

I'm noticing banding in "lossless" (HEIC, q 100) images produced by XnView. (Luckily PNG and JXL lossless output seems great.)
Is this 8-bit limitation the cause? Persists even with NConvert, using "-org_depth".

Update: Trying some alts now. ImageMagick HEIC produces no banding. Can provide sample (or try blurred color gradients).