RE: [APML] Picture Window Pro vs. PhotoShop

[Jerry Lodriguss <jml@astropix.com>]

> > > Photoshop, btw, only really operates in 15 bits, not 16, they
> > > are actually
> > > pulling a trick.
>
>I've not heard of this, can you elaborate?


I first heard of this in a readme file with Eddie Trimarchi's FITS plugin 
for Photoshop.

I corresponded with him and asked him about it. He said it is alluded to in 
the Photoshop SDK, but it is not explicitly stated as to exactly what is 
going on.

He found out when he was testing the 16-bit save in his FITS plugin and 
found only even values after the file was saved. Photoshop apparently 
halves the 16 bit values on opening, and then doubles them on saving.

Eddie said he asked on the Photoshop SDK mailing list which is moderated by 
an Adobe staff member who talked about it matter of factly as if it was no 
big deal and mentioned informally that it was done for performance reasons.

Jerry

Astronomical photography: http://www.astropix.com




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