Perhaps i'm totally doing it wrong, to my understanding, the filter "Color to Alpha" under "Filter Brush" is about to chose a color and then convert that color into alpha values, in GIMP i was very used at that concept:



I then setup the few option that "Filter Brush" has:



and unfortunately got this result over a simple gradient:



i not only didn't got any color erased, but i had this odd effect, i checked that the image were RGB and had an alpha channel, i tried with 'Ignore Alpha' and without it, but it simply doesn't work as i thought it would, there's no documentation and i'm pretty much exploring Krita on my own... so any info regarding this would be of help. GREETINGS!!!!

Hi! Thanks for trying Krita and joining us on the forum. Documentation is indeed a sore spot, but Animtim's dvd project (http://krita.org/component/content/arti ... aining-dvd) should at least partially help there!

About your problem, I need to try and reproduce, but I think that you might actually have found a real bug here. If you want to track our progress on fixing it, you could open a bug on bugs.kde.org. If you want, I can create the bug as well for you.

Not related, but I love the cartoony style of the image you posted (this one:
)

Looking forward to seeing a full image from you!

There is a bug in the color to alpha filter that prevents it from working correctly.

@boudewijn:

yes please! can you create the report of the bug for me? thank you for you answer, definitely looking forward for the fix.

@Kubuntiac:

Indeed, the full drawing is here http://dr-cane.deviantart.com/#/d3imi3m [SPOILER] is kinda curvy jajajaja XD

@slangkamp:

yup, i see now, fortunately isn't big deal, maybe in the future you can include "COLOR ERASER" blending mode for brushes if is easier than fix the Filter Brush thingy,

Thank you for your answers, while the bug still exist i know now is about a bug and not something i'm doing wrong, perhaps, i can mark this thread as solved, thank you!! =D

Looks like we actually have _three_ bugs for this filter:

https://bugs.kde.org/show_bug.cgi?id=273858
https://bugs.kde.org/show_bug.cgi?id=252396
https://bugs.kde.org/show_bug.cgi?id=273288

...

For the color to alpha filter to work, you need to select the copy composition mode (and if you are using the development version of krita, it seems impossible at the moment, but works in 2.3), and make sure to have a threshold superior to 0 (I am going to fix that...)