Hi, On Sun, Nov 2, 2008 at 9:34 AM, Martin Nordholts <enselic@xxxxxxxxx> wrote: > I understand what you mean now. We are not doing the same kind of paring > though. You are pairing layer modes that are cancelling each other out > while I am paring layer modes that give opposite effects on lightness. > To convince yourself of that Multiply pairs with Screen in the latter > case, create an image with two layers, one with a vertical > black-to-white gradient and the other with a horizontal black-to-white > gradient (so that all possible combinations of channel intensities are > blended). Then examine the result of having the top layer first set to > Multiply and then to Screen. Yes, I see what you mean. Overall effect rather than mathematical relation. > >> Linear Burn is exactly a reversed Subtract, yes? that is, >> result = dest - (1-src) >> rather than >> result = dest - src >> ? >> > > Yes exactly, Linear Burn is > > result = dest - (1 - src) = dest + src - 1 > >> * Color mode is markedly inferior to PS Color mode (because it uses >> HSL, rather than LAB colorspace, the transference is not only of color >> data but some intensity data.). It's important to include some Color >> mode, however if we can get Color mode working in LAB space, we should >> probably show that by default and hide old style Color mode. >> > > I agree, the current Color mode and friends can give pretty unexpected > results. Personally I don't think I will put much effort in that in the > near future though. I'm assuming that the separate layer modes will eventually separate into their own files for reasons of speed, in which case this is trivial to implement; request LAB color as the input format, apply normal blending to A and B channels, leave L channel unchanged from dest. I would certainly be willing to do that when the time comes. > >> Personally, only about 7 of the layer modes have any use to me: >> normal dissolve difference multiply divide grainMerge grainExtract >> > > Interesting, what do you use Grain extract and Grain merge for? Colorized shading/lighting. The nice thing about grain merge and extract is they have a very regular effect on intensity, which means it is comfortable to eg. paint using Grain Merge on a Grain Merge-moded layer. If you start with a layer filled with color #808080 which is neutral: Say you have colors #606060 and #a0a0a0, painting with one of those will lighten the layer by 32; if you swap colors you will be darkening the image by 32. Providing layer opacity == 100%, that will result in a literal change of 32 to the underlying image. That predictable symmetry helps. Also, you may have noticed, Grain merge creates complimentary colorings; eg Grain merging bright yellow #ffff90 makes the image brighter and yellower, Grain extracting the same bright yellow makes the image darker and more blue. _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
