note that our input colour profile module has a `BGR linear infrared' profile for this purpose (so you can work on your swapped channels early on in the pipe, channel mixer comes in quite late).
-jo On Fri, Jun 3, 2016 at 9:27 AM, Raymundo Vega <[email protected]> wrote: > First, Thank you so much. > > I was following the photographylife.com tutorial, but stopped when i tried > the channel mixer to move blue to red and green and set the blue to red > plus green minus blue. > > Thanks again, my test photo looks much better now in false color and BW. > > ~raymundo > > "Obscurity is a far greater threat than piracy" > Tim O'Reilly > > On Thu, Jun 2, 2016 at 11:29 PM, Robert William Hutton <[email protected]> > wrote: >> >> IIRC the reason that people play around with custom camera profiles in >> lightroom or photoshop is because their white balance sliders don't go far >> enough to get things into the correct range. There's no such problem in >> darktable, so the process is drastically simpler. >> >> For example, here's a basic process using those Adobe tools that you might >> use as the basis for developing a workflow in darktable: >> >> https://photographylife.com/how-to-process-infrared-photographs >> >> Here's what I've come up with: >> >> Open the channel mixer module. >> >> * Pull down the destination dropdown list, and select blue >> * Right click on the blue slider and type "0" >> * Right click on the red slider and type "1" >> >> You have now put the information from the red channel into the blue >> channel. >> >> * Pull down the destination dropdown list, and select red >> * Right click on the red slider and type "0" >> * Right click on the blue slider and type "1" >> >> You have now put the information from the blue channel into the red >> channel. >> >> Now open the white balance module. I guess the idea here is to play with >> things until you get what you want, whether that be a white ground and blue >> sky or slightly red ground or whatever. There's no right or wrong answer. >> One technique that seems to work for me is to use the spot white balance and >> select some foliage, like leaves or grass on the image. That'll get you in >> the right ballpark. Then play around with the sliders or try selecting >> different parts of the image until you get the colours that you want. Or >> try selecting different things within the image with the spot white balance >> tool until it looks good. >> >> Next, you'll probably need to go into the exposure module and play with >> the black and white points, and then you might want to use the equalizer to >> increase the contrast, and then perhaps color zones or color correction >> (again keeping in mind that red and blue have been reversed). >> >> HTH, >> >> Rob >> >> >> On 03/06/16 14:41, Raymundo Vega wrote: >>> >>> It may be user ignorance/error, i tried channel mixer playing with values >>> there, but i was not >>> able to swap (for instance) blue and red channels like the color profile >>> bgr do. >>> >>> ~rv >>> >>> "Obscurity is a far greater threat than piracy" >>> Tim O'Reilly >>> >>> On Thu, Jun 2, 2016 at 3:59 AM, Robert William Hutton <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> >>> >>> On 02/06/16 20:52, Tobias Ellinghaus wrote: >>> >>> On Thursday 19 May 2016 10:33:47 Raymundo Vega wrote: >>> >>> Hello all, >>> >>> I am playing with infra red photography and need pointers on >>> how to >>> create icc files, i like to try different channel mixtures. >>> >>> >>> I am not aware of any easy to use editor for ICC profiles. What I >>> personally >>> would do is patching the sources of darktable >>> (src/common/colorspaces.c) to >>> create the profile you want and then have it written to disk. But >>> that requires >>> some basic programming knowledge. Maybe someone else has a better >>> idea? >>> >>> >>> Well, infrared photography generally involves using a really extreme >>> white balance and/or >>> switching the red and blue channels. Can't you just do that using >>> the white balance and channel >>> mixer modules? No icc required. I was going to do a video on it at >>> one point, but having a >>> baby has kinda crimped my free time. >>> >>> Regards, >>> >>> Rob >>> >>> >>> ____________________________________________________________________________ >>> darktable user mailing list >>> to unsubscribe send a mail to >>> [email protected] >>> <mailto:darktable-user%[email protected]> >>> >>> >> >> ____________________________________________________________________________ >> darktable user mailing list >> to unsubscribe send a mail to >> [email protected] >> > > > ____________________________________________________________________________ > darktable user mailing list to unsubscribe send a mail to > [email protected] ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected]
