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Re: Any Minolta/Sony users ...

nospam
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SubjectRe: Any Minolta/Sony users using UFRaw and GIMP?
Fromnospam
Date2014-04-21 01:45 (2014-04-20 19:45)
Message-ID<200420141945258608%nospam@nospam.invalid>
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Newsgroupsrec.photo.digital
FollowsAlan Browne
FollowupsAlan Browne (1d, 21h & 37m)
Alan Browne (5d, 14h & 47m)
In article <b-qdnUuFUvwIp8nOnZ2dnUVZ_vudnZ2d@giganews.com>, Alan Browne <alan.browne@FreelunchVideotron.ca>wrote:

PeterN
The only time you might see a difference would be if there were colors in the LAB spectrum that are not in the RGB spectrum, and those differences would rarely be noticable in a photograph.

Alan Browne
A good point - but nospam's contention is conversion differences.

Let's color the situation. The files were taken from raw, reduced in size, saved as TIFF in each RGB and Lab. Re-loaded and compared (differenced). There is not a hint of delta.

http://tinyurl.com/m35p59t RGB

http://tinyurl.com/mldetvx Lab

http://tinyurl.com/mvl6vwj Diff

there's a difference there too.

i did: image/duplicate, append -converted to the name. image/mode/lab image/mode/rgb image/calculations, original on top, converted below, subtract mode

optionally, just before the calculation step, switch between the two images while looking at the histogram palette. there's a difference. then do the calculation step.

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Alan Browne (1d, 21h & 37m)
Alan Browne (5d, 14h & 47m)