Re: Applying LUT to PNG image changes bit depth

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Re: Applying LUT to PNG image changes bit depth

Neil Fazel
Hi Wayne,

> Applying a lookup table does not change the bit depth when saving in TIFF format.
   
Thanks for the info. My understanding is that TIFF formats are lossy, so for quantitative work on an image, only .txt or .png image formats are appropriate. I think the solution for me is then to save the PNG images in grayscale, so that the bit depth is maintained.

Neil
 

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Re: Applying LUT to PNG image changes bit depth

ctrueden
Hi Neil,

> My understanding is that TIFF formats are lossy, so for quantitative
> work on an image, only .txt or .png image formats are appropriate.

Not typically. TIFF is a container format, so it depends what style of
compression you use. The vast majority of TIFFs in the wild use either no
compression, or LZW, both of which have no loss. You can store
JPEG-compressed data in a TIFF, though, which would be lossy. But ImageJ
certainly does not do this when saving TIFFs.

The TIFF format is much more flexible for scientific images than PNG, so
I'd recommend TIFF (well, OME-TIFF, actually [1]), as your preferred
interchange format.

As for raw data, definitely keep the original data produced by your
acquisition system, since every conversion step is likely to lose some
metadata.

Regards,
Curtis

[1] http://openmicroscopy.org/site/support/ome-model/ome-tiff/

On Wed, Apr 15, 2015 at 3:40 PM, Neil Fazel <[hidden email]>
wrote:

> Hi Wayne,
>
> > Applying a lookup table does not change the bit depth when saving in
> TIFF format.
>
> Thanks for the info. My understanding is that TIFF formats are lossy, so
> for quantitative work on an image, only .txt or .png image formats are
> appropriate. I think the solution for me is then to save the PNG images in
> grayscale, so that the bit depth is maintained.
>
> Neil
>
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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