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AAARRRRGGGGHHHH masks.

Mar 22, 2012, 20:39
Post: #1
AAARRRRGGGGHHHH masks.
Ok i give up.
I am trying to add a grey scale mask to a layer so I can alter some game files .But I must be missing something blindingly obvious.
here is how I create a mask in PSP6.
first I duplicate the base layer.
Then I adjust the saturation to -100%(grey). Then I adjust the lightness to +100%..This gives a grey scale image.
I then increase the brightness by 25% and the contrast by 50%. This gives a grainy bright and high contrast grey scale image.
I then create a mask and then add the mask to a blank layer.
This allows me to spray away to my hearts content and leaves the main detail on the original image untouched.
By this method I can add mud effects to tank tracks in games and still see the original link details through the mud.
But I am having major issues trying to achieve this effect in gimp.At the moment this hurdle is stopping me getting to grips with gimp.

Please help.
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Mar 22, 2012, 20:54
Post: #2
RE: AAARRRRGGGGHHHH masks.
Where does it go wrong? Can you show an example?

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Mar 22, 2012, 21:17
Post: #3
RE: AAARRRRGGGGHHHH masks.
(Mar 22, 2012 20:54)ofnuts Wrote:  Where does it go wrong? Can you show an example?

I'm not sure where it goes wrong.
but here is the original image i am trying to mask.

[Image: Ferdinand.jpg]

and here is the effect I am trying to achieve in gimp.

[Image: Ferdinand_track.jpg]

The above effect was done using the method I posted in PSP6.I would make a mask from this grey scale image and then add it to a blank layer.This then allows me to spray mud around the track and keep the black details
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Mar 22, 2012, 22:34 (This post was last modified: Mar 22, 2012 22:36 by ofnuts.)
Post: #4
RE: AAARRRRGGGGHHHH masks.
(Mar 22, 2012 21:17)gautrek Wrote:  
(Mar 22, 2012 20:54)ofnuts Wrote:  Where does it go wrong? Can you show an example?

I'm not sure where it goes wrong.
but here is the original image i am trying to mask.

[Image: Ferdinand.jpg]

and here is the effect I am trying to achieve in gimp.

[Image: Ferdinand_track.jpg]

The above effect was done using the method I posted in PSP6.I would make a mask from this grey scale image and then add it to a blank layer.This then allows me to spray mud around the track and keep the black details
I go from your first image to this:
[attachment=1040]
using this curve in the Curves tool:
[attachment=1039]

For the rest, the typical way to do this would be to use layer modes (typically putting the top one in "overlay" mode but other modes are possible).

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Mar 23, 2012, 20:30
Post: #5
RE: AAARRRRGGGGHHHH masks.
(Mar 22, 2012 22:34)ofnuts Wrote:  For the rest, the typical way to do this would be to use layer modes (typically putting the top one in "overlay" mode but other modes are possible).

Thanks for that info mate.But I still can't work out how to add the mask to a layer so that I can spray into the layer and the black bits are not covered.I just can't seem to grasp the different terminology in gimp.
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Mar 23, 2012, 22:02
Post: #6
RE: AAARRRRGGGGHHHH masks.
In Gimp's terminology (but AFAIK this is similar to Photoshop) there are two kind of masks:

- selection masks (often called just "selection" but it is sometimes ambiguous). This tells Gimp what pixels will be affected by operations (paint, clipboard copy/cut, geometric transforms)(the selection is associate to the whole image, affected pixels are the intersection of the active layer and the selection mask)

- layer masks, that control the transparency of a layer (can be see as an image of the alpha-channel). A layer mask is associated to one single layer.

- Both types of masks can be stored to and set from "Channels"

- There are plenty of tools to create a selection mask from an image (select by color, magic wand...)

- There are also many ways to set a layer mask from an image.

But you haven't shown us so far the kind of image you do on PSP with both tracks and mud/dirt.

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Mar 23, 2012, 23:21
Post: #7
RE: AAARRRRGGGGHHHH masks.
(Mar 23, 2012 22:02)ofnuts Wrote:  But you haven't shown us so far the kind of image you do on PSP with both tracks and mud/dirt.

Thanks for your help mate.
here is a quick rough version of the same track with some mud added.
[Image: Ferdinand_track.jpg]

As you can see I have quickly added a mud colour to most of the track and the mask stops me over spraying the black holes(which are transparent in the game as are most of the other black areas round the side) and the detail of the link,I have added some blobs of mud texture on a plain top layer.I deliberately do this to obscure some of the square black holes and the detail on the track link.As mud tends to build up and clog up tyres and tracks. Plus i have added a silver stripe over the raised part of the track which would be in contact with the ground.
So I need a mask which will stop me over spraying black on my image.
I hope this helps
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Mar 23, 2012, 23:44
Post: #8
RE: AAARRRRGGGGHHHH masks.
(Mar 23, 2012 23:21)gautrek Wrote:  So I need a mask which will stop me over spraying black on my image.
I hope this helps
Color selector (Bycolorselect) and click on black, then invert the selection.

But if you apply paint on a layer above, that you put in "overlay" mode, you will see your black being miraculously preserved.

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Mar 26, 2012, 21:31
Post: #9
RE: AAARRRRGGGGHHHH masks.
thanks for you help mate.
I have finally sorted it.I popped round a mates today and we are both gimp novices.But with a combination of his limited knowledge and your help we have sorted it.we have ended up using the gegl function and using the c2g mode.
Now i have made a couple of masks I am getting to learn how to add them to a layer.
My next question is a lot simpler.
I need to be able to drop the brush opacity. which I can do.But I also need to drop the density . But I can't find this function or is it called something else?
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Mar 26, 2012, 22:03
Post: #10
RE: AAARRRRGGGGHHHH masks.
C2G (as the name says) is mostly converting the image to B&W. C2G will however, when properly used, create HDR-like local contrast. But it's a pretty long processing, there can be more suitable and faster ways to obtain a B&W mask for your purposes.

For me density=opacity unless you are talking B&W photography in which case density=blackness. But all in all the 4 brush variables you can play with are R,G,B, A, the first three from the foreground color and the last one from opacity.

This said, I don't find much use for brush opacity (unless used through a pressure sensitive tablet), since I achieve the same result with a fully opaque brush on a layer for which I adjust opacity, with the added benefit that I can adjust the opacity later.

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Mar 27, 2012, 20:05
Post: #11
RE: AAARRRRGGGGHHHH masks.
here on the left is the effect I am trying to achieve which i have done using psp and a texture on my brush.As you can see the the brush leaves a bumpy looking texture which I can build up to look thicker by over spraying the area.
[Image: mud1.jpg]

On the right is all I get when I use the same brush texture in gimp.
Messing about with the opacity just fades it out more.I must be missing something as I can't for the life of me work out how to make the brush in gimp work the same as PSP.I have tried dissolve and other things and am having no joy.
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Mar 27, 2012, 22:08 (This post was last modified: Mar 27, 2012 22:21 by ofnuts.)
Post: #12
RE: AAARRRRGGGGHHHH masks.
Try a completely different technique:

- add layer above
- bucket-fill using dirt/sand pattern
- add layer mask and init to black (layer becomes transparent)
- paint mask with white using airbrush, or plain brush with light opacity (20%).

Sand texture brushed over tile texture:

[attachment=1050]

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