Nikon D750 .nef raw conver

[snibgo]

IM runs the delegate command, then tries to read the output from that. It expects the output from the delegate to be a file named the expansion of %o (which won't have an extension like ".tif"). So change "%u.tif" to "%o". Commands like "magick LUMINANCE:AGA_3443.NEF x.png" will then use that delegate, and work without complaint.

EDIT to add: "%u" is useful as an intermediate file when the delegate involves two or more commands, eg dcraw to write %u, then magick to read %u, process it and write %o. For example, the delegate line (for Windows)...

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  <delegate decode="LUM2" stealth="True" command="cmd.exe /c (F:/pictures/dcrawag.exe -q 3 -o 0 -4 -r 1 1 1 1 -S 65535 -T -O &quot;%u&quot; &quot;%i&quot;) &amp; (magick TIFF:%u -colorspace Gray -resize 600x600 %o)"/>

... means the IM command ...

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magick LUM2:AGA_3443.NEF x.png

... creates a small grayscale version of the input raw file.

[whugemann]

Although your suggestion works and solves my actual problem, I am not quite convinced: The result is pretty much the same as that of the batch file:

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C:\Programme\ImageMagick7\dcraw.exe -q 3 -o 0 -4 -r 1 1 1 1 -S 65535 -T -O "%~dp1temp.TIF" %1
magick "%~dp1temp.TIF" -distort barrel "0.0099 -0.0678 0.0014 1.0511" "%~dpn1.TIF"
del "%~dp1temp.TIF"

i.e. it hard-codes the conversion, whereas the intention of a delegate definition should be to define a way to turn the input file into something readable for ImageMagick – and leave me with the option to provide any command line options that come to my mind.

Or do I get something wrong?

[snibgo]

... and leave me with the option to provide any command line options that come to my mind.

IM has no mechanism for taking arbitrary options from its command line and passing those to the delegate.

That's one reason why I don't use IM to call dcraw to read raw files. Instead, I use dcraw directly.

[whugemann]

IM has no mechanism for taking arbitrary options from its command line and passing those to the delegate.

I don't want to pass parameters to the delegate; I would like to be to be free of choice in regard to the operations that magick performs on the temporary file, for example scaling, a 3x3 median, embed a logo or apply a false colour palette.

[snibgo]

Sorry, I don't understand your question.

IM calls the delegate and reads the result into memory. Then IM can do any command line options, such as "-flip -flop" and write the image to a file:

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magick LUM2:AGA_3443.NEF -flip -flop x.png

[whugemann]

I think our misunderstanding arises from the point that your suggested delegate-command

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<delegate decode="LUM2" stealth="True" command="cmd.exe /c (F:/pictures/dcrawag.exe -q 3 -o 0 -4 -r 1 1 1 1 -S 65535 -T -O &quot;%u&quot; &quot;%i&quot;) &amp; (magick TIFF:%u -colorspace Gray -resize 600x600 %o)"/>

performs the entire job on its own. I now tried

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<delegate decode="LUM2" stealth="True" command="dcraw.exe -q 3 -r 1 1 1 1 -T -O &quot;%o&quot; &quot;%i&quot;"/>

and found that working as you said. I see: Most entries in delegates.xml use %o as the pivot (i.e. intermediate format), whereas the (superfluous) dng-delegate-entry is

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<delegate decode="dng:decode" stealth="True" command="dcraw.exe -6 -W -O &quot;%u.ppm&quot; &quot;%i&quot;"/>

using %u.ppm as the pivot.

As I understand %o, it would mean that if you convert to a lossy format such as JPEG in the end, the intermediate file would also be JPEG, i.e. causing two lossy compressions (?).

Does

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decode="dng:decode"

have any special meaning in comparison to just

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decode="dng"

?

[snibgo]

I think our misunderstanding arises from the point that your suggested delegate-command ...

I invented an example to show the use of %u as in intermediate file in a delegate that used two commands. The commands I used were not important. You need only one command, so don't need to use %u. Sorry if I confused you.

As I understand %o, it would mean that if you convert to a lossy format such as JPEG in the end, the intermediate file would also be JPEG, i.e. causing two lossy compressions (?).

At the end of the IM command, you might write the image to JPEG or any other format. That has no effect on what happens within the delegate.

I don't know the difference (if any) between ...

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decode="dng:decode"

... and ...

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decode="dng"

[fmw42]

See https://imagemagick.org/script/formats.php

It says:

DNG R Digital Negative Requires an explicit image format otherwise the image is interpreted as a TIFF image (e.g. dng:image.dng).