GIMP Version: 2.6.11
Operating System: Windows
OS Version: XP - SP3
GIMP Experience: Intermediate Level

im watching Alex tutorials as well, they are very good !

you can ask him directly, here:
http://gimpedtutorials.com/index.php/askgimped/

i think he has an account here too, doesnt he ?!

about your picture, i will have a go at it
my guess is, thats its very difficult because there isnt enough contrast between the background and the car, so might use the path tool instead

is that the original picture, or is there a bigger version ?

ORIGINAL VERSION......

well here is the problem, as i see it

even if you try Alex trick with changing the colors so that the desaturation process is enhanced, there are other portions of the picture that become green



even if you use a rough selection, the green still bleeds into the background



i think this isnt a very good picture to work with in the first place
you could try making a path around the car, use the selection for creating the white in a layermask, and then tweak the layermask manually with the brush
but i think thats still very hard

[quote="Esper"]well here is the problem, as i see it

even if you try Alex trick with changing the colors so that the desaturation process is enhanced, there are other portions of the picture that become green



even if you use a rough selection, the green still bleeds into the background

to answer your question: yes, i think basically this works with every picture

in a layermask you try to tweak the picture so that everything you want is white and everything you dont want is black

Alex just exploits the principle to his advantage that GIMP thinks the color blue is the darkest and the color green is the lightest when desaturating

I'm not criticizing rdgracer71 but have you got jelly underneath your Caps Lock key?

sorry about the caps...it was done by mistake....i wasn't yelling at anyone ....sorry about that guys

When trying to figure out the best way to isolate an image, I like to use http://gimpfx-foundry.sourceforge.net/b ... tract.html

This extracts all the colours into separate layers you can look at and decide how they can best be used to get a decent mask.

I used the difference of red and blue for this image, but it still needed a lot of manual touch-up, and the jpeg artifacts make it a pain to work on:



EDIT: Added the xcf file in case you want to see the masks I used.

-Rob A>

phew RobA, theres a lot going on in that xcf

it feels like this technique with the script you used is way too complex for my level of expertise

I downloaded it too and I think it is a fantastic job.
I must admit that I don't use masks as often as I should, but I would like to learn more about them. I still find them quite confusing. I have seen several tutorials but yet to see one that I can completely understand.

@RobA
Syncronicity .. i was just thinking of that filter, very handy and a layermask based on channel here seems the best solution, even if a bit of manual retouch of the mask will be always needed

i was just thinking that would be nice rewrite the channel extract script as Gmic filter also because Gmic support more color spaces and so would be more useful channels available.

If i remember well i already try and for some reason was more difficult then i hoped (split the channels was trivial but to convert in layers was a tricky "normalization" step to deal with )

about the Lasm script i hate see yet another new weird menu added in the image windows, because just 1 new script

So i changed my copy , instead then in a new Fx Foundry/toolbox menu the script will be listed in Colors/Components
( close to the Channel Mixer ) with the name Channels to new Layers, name that correspond to what the script does

i included the edited script as attachment

Thank you pc

I always wondered why you cant edit each of the RGB channels seperately like you can in Photoshop. Boy I wish I could do that.

Alan

You can open your channels dialogue and select/deselect the channels you wish to work with.

i believe more handy convert them to layers to edit but as Erisian say is doable.

If converted to layers is possible use Colors/Components/Compose channels to recombine in a image

I don't know why but when I disable the channels I don't want to work with by clicking on the eyeball and then draw on the canvas with the channel selected that I want to draw on it effects all the channels. Same with filters if I run a filter it effects all channels. It draws on the layer I have selected and therefore effects all the channels. Thats the way it has always been even when I ran 2.6.

I can convert a channel to a layer by right clicking channel to selection and paste on a layer. Is that what you mean by convert to a layer.

Alan

I have found that if I do a Channel to Selection for each color and make a new layer for each color and paste the RGB color (the exact RGB color from the color pallet ie 255 red - 255 green etc), for each channel and then set the layers to screen on top of a black background it gives me the exact same image with each layer avaliable for editing with filters or brushes. I could then do a Layer New from Visible to render a single layer result.

Its a lot of work though.

Alan

Here is an example:


Alan