Episode 158: Three kinds of Particles

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[flattr /]There was a question left open in the last show: How to create a random pattern of particles that follow a gradient in density.

I got three answers. One from Benton – just use a brush with absurdly high jitter. Then I got the help that I asked for from Philippe and finally thought about a way myself. I started with Philippe’s tutorial for making a starfield.

And I recommend the Youtube channel of GimpTricks.

The TOC (by Kevin)

00:25 Welcome to GimpTricks ??
01:02 Welcome to Meet The Gimp
01:40 Benton’s solution to the random particles problem:
02:40 – Set Jitter on the paintbrush tool by typing
03:45 – Adjust the jitter to change the density
05:18 Philippe’s solution:
05:34 – Put a gradient on a quickmask
06:05 – Add noise to the gradient and fill the selection with black
06:47 – Use the threshold tool to adjust the density
07:17 Rolf’s solution:
07:33 – Fill a black layer with HSV Noise
08:48 – Add a new transparent layer in subtract mode
09:03 – Fill the subtraction layer with a gradient
09:50 – Use the threshold tool to control the density
10:45 – Bigger blobs needed
10:50 – Select the blobs using the colour selection tool and fill with blue
11:16 – Stroke the selection and Gaussian blur the blobs
12:45 – Use a picture instead of a gradient
14:51 The End

Sorry, not here up to now.

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort and Philippe Demartin is licensed under a Creative Commons Attribution-Share Alike 3.0 Germany License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.

9 thoughts on “Episode 158: Three kinds of Particles

  1. Try this for a TOC:

    http://meetthegimp.org/episode-158-three-kinds-of-particles/
    Episode 158: Three kinds of Particles
    00:25 Welcome to GimpTricks ??
    01:02 Welcome to Meet The Gimp
    01:40 Benton’s solution to the random particles problem:
    02:40 – Set Jitter on the paintbrush tool by typing
    03:45 – Adjust the jitter to change the density
    05:18 Philippe’s solution:
    05:34 – Put a gradient on a quickmask
    06:05 – Add noise to the gradient and fill the selection with black
    06:47 – Use the threshold tool to adjust the density
    07:17 Rolf’s solution:
    07:33 – Fill a black layer with HSV Noise
    08:48 – Add a new transparent layer in subtract mode
    09:03 – Fill the subtraction layer with a gradient
    09:50 – Use the threshold tool to control the density
    10:45 – Bigger blobs needed
    10:50 – Select the blobs using the colour selection tool and fill with blue
    11:16 – Stroke the selection and Gaussian blur the blobs
    12:45 – Use a picture instead of a gradient
    14:51 The End

  2. A fourth method:

    Start with a white BG layer.
    Add a new layer filled with black (or other color of choice).
    Add a layermask to the black layer and use the Blend Tool to create a black-to-white gradient extending from the top of the layermask to the bottom.
    Set the mode of the black layer to “Dissolve” and adjust its Opacity to suit.

    (saulgoode in the forum)

  3. No idea what you are talking about – which colours does Microsoft use with a curve?

    (Commercial link removed – please link only do personal home page or on topic stuff!)

  4. I think Rolf is loaded with work atm, it’s testing time here in Germany — I can hardly think of a more stressful time for teachers.

  5. Lots of work, a week zonked out with a cold, a new task at school and spring tiredness kept me away from here. But tomorrow is the last day before the easter break – I’ll be back soon.

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