On Tue, Feb 5, 2013 at 7:54 PM, Russell Edwards <[email protected]> wrote: > Thanks for the relevant doco link.
yeah, sorry it doesn't solve your problem. the levels module is in Lab and works on L only. i would try to play with the tonecurve and individual a/b color contrast curves for your usecase: http://www.darktable.org/2012/02/mastering-color-with-lab-tone-curves/ -jo > So it sounds like I was deluded in thinking I was altering R, G, B > levels independently with the histogram. > > If I get time I might have a look at contributing some code. (I have > also been wanting to add a loupe to lighttable.) > > Russell > > On 2013-02-04 08:27, johannes hanika wrote: > >> On Mon, Feb 4, 2013 at 9:57 AM, Russell Edwards <[email protected]> >> wrote: >>> Hi, >>> >>> I have some digital photos of faded old colour prints. The R, G, B >>> histograms are squashed and shifted with respect to eachother due to >>> the >>> different fading characteristics of the different pigments in the >>> paper. >>> >>> It seems to me the best way to fix what I am seeing would be if I >>> could >>> apply the exposure or levels module to the R, G, B modules >>> independently. >>> >>> What's the closest feature in darktable to achieve such a thing? >>> >>> I can kind of do it dragging the histogram but that is extremely >>> slow >>> and jerky, and I can't find which module actually implements that >>> processing, nor documentation of it, so am hesitant to use it. >> >> http://www.darktable.org/usermanual/ch03s04s05.html.php#idp619488 >> >>> I can partly do what I need by playing with channel mixer or color >>> correction, but it is not flexible enough to really do what I need >>> to >>> do, which to first order is move the left end of the red histogram >>> to >>> the left and the right end of the red histogram to the right. >>> >>> Thanks in advance for any help you can offer. >>> >>> Russell >>> >>> >>> >>> ------------------------------------------------------------------------------ >>> Everyone hates slow websites. So do we. >>> Make your web apps faster with AppDynamics >>> Download AppDynamics Lite for free today: >>> http://p.sf.net/sfu/appdyn_d2d_jan >>> _______________________________________________ >>> Darktable-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/darktable-users > > > ------------------------------------------------------------------------------ > Free Next-Gen Firewall Hardware Offer > Buy your Sophos next-gen firewall before the end March 2013 > and get the hardware for free! Learn more. > http://p.sf.net/sfu/sophos-d2d-feb > _______________________________________________ > Darktable-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/darktable-users ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
