On Tue, 2 Feb 2010 16:54:09 -0800 (PST) Rich Evans <reva...@yahoo.com> wrote:
> I'm grateful for the replies I have received, but I was thinking that > if there isn't a well-known tool or method already, that maybe > someone could point me to a site that describes how custom filters > can be made from scratch. I'm not afraid to learn what I need to to > make the filter, ...I've just never done it before. *grin* I just > need someone to point me to a decent tutorial (I can do c programming > if that's what it is, but my working assumption is that, all things > being equal, it should be easier to make a filter for GIMP than it > would be to write a c program from scratch).Would anyone consider > this... easy? > > continue thanks, > -Rich > > > > ----- Original Message ---- > From: Cédric Gémy <radar.ma...@free.fr> > To: Gimp-user@lists.XCF.Berkeley.EDU > Sent: Tue, February 2, 2010 5:58:51 PM > Subject: Re: [Gimp-user] how to invert greyscale values only... > > not completely satisfied with sven's method, working on some pictures > but not any, depending on the shades. > I used to do it in CMYK a long time ago with photoshop by just pushing > the image to CMYK and inverting the K curve. > I guess something might be done with decompose color filter or so. But > the quicker/best average i've found is just adding a mask based on the > layer (L from Lab or N form CMYK could be used too), and play with the > curve to adapt to the shades+refine with brush on mask. It takes few > seconds if the picture is not too complex. Then put a white layer > below and it's quite done. > But i'm not completely satisfied with it. If you look at http://www.gimp.org/tutorials/Color2BW/ I am pretty sure all those techniques can be scripted with with either scheme or python. Owen _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
