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Posts posted by Romur

  1. This tutorial can be executed with a few clicks, but since the bracketing technique is not widely used and is usually supported by complex pieces of software, I thought it was worth describing the process.

    If you have a high-contrast scene, with dark and bright areas, a single shot with the default settings of your camera will not give a good result. Bracketing is the process of taking three photos; one using the camera’s recommended settings, one underexposed, and one overexposed (many cameras can automatically shoot a bracketed series of pictures: RTFM). It is better to use a tripod so that each image is perfectly aligned with the others. You should also set manually the white balance and ISO sensibility.

    You can then combine the three shots to get a picture where all areas have correct exposure. How? With Photoshop or with the “exposure blend” plugin for Gimp. Or you can get a decent result with Paint.net and the “Alpha Mask Import” Plugin.

    Step 1

    Open the underexposed and overexposed pictures (I will not use the third one, you can combine only two pictures with this technique).


    Copy-Paste the darkest over the brightest into a new layer.

    Step 2 if you did not use a tripod

    Open the upper layer properties window and select the mode “Difference”

    If there is an alignment problem, you will notice white lines along the edges.


    Select all the upper layer, select “Move selected pixels” in the tool bar, and move carefully the upper layer, pixel by pixel, using the arrows of the keyboard until the picture is almost completely dark.


    Unselect (press Esc) and set back the layer mode to Normal.

    Step 3

    Select the picture in the upper layer and copy it (Ctrl A ; Ctrl C). Then unselect all (Esc).

    Open Effects/Alpha Mask… and in the settings window select only “Paste from clipboard”.

    Since the alpha mask is the picture itself (from the clipboard), the darkest parts of the upper layer will become transparent and the corresponding parts of the brightest layer will appear.


    Click Ok. You are done. The final picture is in the middle and is a mix of the two others (the wall on the right is rather bright but the sky is colorfull).


    Note: For step 3, you can also use the Alpha Mask plugin from the Illnab1024's Plugins.

    Bonus: What if you did not take a set of bracketed pictures? Open your only picture, adapt Brightness/Contrast to generate one overexposed and one underexposed and go to step 1.

  2. Here is a mountainous planet (usually you can’t see the mountains from space, but I wanted to do it anyhow).

    My solution is :

    • Add a new layer under the clouds
    • Select the continents
    • On the new layer, create clouds with Scale 250 and roughness 1
    • Use Dents with Scale 200, Refraction 80, Roughness 10, Tension 10
    • Unselect all
    • Use the Bucket with the “Global” flood mode to fill the empty areas with a neutral grey (code 808080)
    • Emboss
    • Set the layer blending mode to Overlay


  3. Wonderful !

    I would just suggest to improve the realism of the clouds by adding a few Distort/Twist effects.

    In the following example I have used four twist effects with Amount between 20 and 10 and Size between 0,5 and 1.

    I am also trying to add a few mountains, but I am not happy about the result.


  4. That is a nice trick

    You get a better result with Distort/Twist if you ran Distort/Sin Waves before. Otherwise, the extremities of the swirl remain “flat”, especially with a low distortion. But I’d just like to mention that you can work around if you do not have the Sine Waves plugin.

    The solution is to add a new layer on top and make a radial gradient with primary color fully transparent and the secondary colour black. This layer will hide the extremities of the swirl as shown below (left without sin wave and without mask; right without sin wave but with the mask).


    With a higher distortion (like the galaxy) this default does not show and the sin wave pre-processing is not necessary.


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