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ggolggoli / delaboratory

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Conversion to BW #39

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Currently conversion to BW can only be done from RGB and by mixing RGB 
channels. It would be very useful to be able to mix it from the other spaces - 
LAB and CMYK being the ones that are quite useful.

Original issue reported on code.google.com by alexey.d...@gmail.com on 14 Feb 2012 at 11:28

GoogleCodeExporter commented 9 years ago 
Yes, this is also feature which will be added in future.

Please propose formulas to calculate BW from CMYK or LAB.
In CMYK I think we could just mix channels as in RGB.
But what about LAB?
Converting to BW by just using L channels is not really impressive, so how to 
use AB channels? I could think only about blending them on L.
And same with LCH?

Original comment by jacekpop...@gmail.com on 14 Feb 2012 at 11:47

GoogleCodeExporter commented 9 years ago 
I am not sure about the formula in LAB (can't see the immediate use of AB) but 
my need was to produce initial BW from LAB L channel only and I found no easy 
way to do it currently? Perhaps it is there but it is not immediately obvious?

I can do it easily in say PS - where as Dan says in his book you just select L 
and do convert to BW which drops the other two channels.

Original comment by alexey.d...@gmail.com on 14 Feb 2012 at 11:57

GoogleCodeExporter commented 9 years ago 
it's done in 0.6.9.1

Original comment by jacekpop...@gmail.com on 26 Mar 2012 at 10:03