Re: Pictures wanted: D200/20D banding example


<JPS@xxxxxxx> wrote in message
news:tjpd4215tp9jr7h3j81ffdgkmjdup4noc1@xxxxxxxxxx
SNIP
What is the PGM format?

"Portable Gray Map" is a binary file with an ASCII header describing a grayscale image, and it can be converted by e.g. Photoshop or ImageJ:
<http://netpbm.sourceforge.net/doc/pgm.html>

That's what I get with "-4", rather than PPM.

Yes, it is a Bayer CFA mosaiced/Raw grayscale file. Only after demosaicing its data, it can be saved as a linear gamma 3-channel 16-b/ch file.

The RAW converts to full scale in this format. When I
convert to PSD (-3), I get 1/16 full histogram in PS.

In addition, the DCraw results multiplied by an appropriate -b
(and an -n with an optional -r and -l) parameter will represent
a color-balanced 16-b/ch conversion from RAW.

For the conversions, yes, but "-b" is totally ignored with the "-D"
argument,

Yes, it either is Raw bayerized data, or one is allowed to manipulate the parameters.

and PS micro-mutilates the data upon loading; 4095 values
merged into 2048.

I use ImageJ to read the data, because it is apparently better at keeping the Max.value in the file's header intact. There is still some testing to be done.

Bart

.

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