Commit 23f9d7a9 authored by Niklas Mattisson's avatar Niklas Mattisson

Modified ChangeLog. Now uses <image> Filter -> Path instead of

Modified ChangeLog.
Now uses <image> Filter -> Path instead of <image>Filter->Path to make it more visible.
Fixed a few broken links.
Add the original tutorial link to Custom_Brushes.
parent 864a83e2
2003-04-09 scizzo <scizzo@gimp.org>
* tutorials/*: Now uses <image> Filter -> Path instead of
<image>Filter->Path to make it more visible. Fixed a few
broken links. Add the original tutorial link to Custom_Brushes.
2003-04-09 Carol Spears <carol@gimp.org>
* admin/gimp-web-urls, added some, fixed others.
......
......@@ -153,7 +153,8 @@
</p>
<p>
Select the original text layer (the one you added some color to) and do the Alpha to Selection trick again.
Right click on the image and use <span class="filter">&lt;Image&gt;Select-&gt;Grow</span>. This will make the new selection larger by a number of pixels -
Right click on the image and use <span class="filter">&lt;Image&gt; Select -&gt; Grow</span>.
This will make the new selection larger by a number of pixels -
I used a value of 2 pixels. Once you have a selection, be sure to reselect the new layer (outline) so that you can
fill it (step 17). And below is what it looks like.
</p>
......@@ -221,7 +222,7 @@
<p>
This. Click inside the bezier path once you close it (close it by clicking one the first node).
This will create a selection.
Use <span class="filter">&lt;Image&gt;Select-&gt;Feather</span> to feather (blur) the selection. I used a value of about 10 pixels.
Use <span class="filter">&lt;Image&gt; Select -&gt; Feather</span> to feather (blur) the selection. I used a value of about 10 pixels.
</p>
<h2>Step 23</h2>
......@@ -282,7 +283,7 @@
<p>
With a little playing around you can get to this. I duplicated the rust layer and moved them (the original rust and the copy) down the stack until
the highlight and lowlight layers were above them. I also duplicated the original text layer, switched on Keep Trans., and used
<span class="filter">&lt;Image&gt;Render-&gt;Clouds-&gt;Solid Noise</span> to add a bit of interest to the layer.
<span class="filter">&lt;Image&gt; Render -&gt; Clouds -&gt; Solid Noise</span> to add a bit of interest to the layer.
Try using the Curves tool to help with this.
You may also notice that the outline layer is blurred. Sometimes this can help.
The idea is, try stuff and find out.
......
......@@ -18,7 +18,7 @@
</p>
<p>
On the left you we see the original image that is about to be thresholded, and on the right side we see the result. The default settings
for the Threshold plug-in were used (<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Threshold</span>). The resulting image is very blocky and aliased.
for the Threshold plug-in were used (<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Threshold</span>). The resulting image is very blocky and aliased.
</p>
<h2>The Curves Trick</h2>
......@@ -30,7 +30,7 @@
First duplicate the image layer by going to the layers dialog, making sure the image layer is selected, and clicking the duplicate button
(fourth from the left). We can use the original layer for some color tricks later. Now the next thing is to desaturate the image
(Image|Colors|Desaturate). This way the colors wont interfere with the fake thresholding. When the layer is grayscale, select the curves
plug-in (<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Curves</span>). Now we can play with the value "channel".
plug-in (<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Curves</span>). Now we can play with the value "channel".
The image on the left displays the settings used for the example image. The space between the two dots determines how much aa the
resulting image will have. The wider the gap, the more grayscale values it will have, and vice versa. The resulting image can be seen on
the right.
......
......@@ -150,7 +150,8 @@
<p>
produces a new gimp image of type RGB and size 100x150.
<br /><br />
All teh functions of the PDB may be accessed through the DB browser that is available from the main menu through Xtns -&gt; DB BROWSER....
All the functions of the PDB may be accessed through the DB browser that is available from the main menu through
<span class="filter"> Xtns -&gt; DB BROWSER</span>....
E.g. the DB Browser entry for uni-img, which we will define in the example below looks like this:
</p>
<p class="images">
......@@ -248,13 +249,14 @@
SF-COLOR "color" '(255 127 0))
</pre>
<p>
To test the script save it in $HOME/.gimp-1.2/scripts/uni.scm and then select Xtns/Script-Fu/Refresh:
To test the script save it in $HOME/.gimp-1.2/scripts/uni.scm and then select <span class="filter">Xtns -&gt; Script-Fu -&gt; Refresh</span>:
</p>
<p class="images">
<img src="refresh.png" alt=""/>
</p>
<p>
The script <b>Uniform image</b> should now appear in the pulldown menu Xtns/Script-Fu/Tutorials/Uniform image.
The script <b>Uniform image</b> should now appear in the pulldown menu
<span class="filter">Xtns -&gt; Script-Fu -&gt; Tutorials -&gt; Uniform image</span>.
Selecting this script results in the following popup:
</p>
<p class="images">
......
......@@ -14,25 +14,30 @@
<img src="after.jpg" alt=""/>
</p>
<p>
In this tutorial I'll show you how to do blend two different exposures of the same scene that you would like to combine to get the best parts of both images.
In this tutorial I'll show you how to do blend two different exposures of
the same scene that you would like to combine to get the best parts of both images.
This procedure works best if you have:
</p>
<ol type="A">
<li>(obviously) have shot two different exposures that would be pleasing to combine,</li>
<li>had the camera mounted on a tripod (not strictly necessary, but helps greatly in aligning the images),</li>
<li>the scenes are not too different at the boundaries of the blend. If the scene has changed too much (trees blowing, waves, people or cars moving, etc.
<li>the scenes are not too different at the boundaries of the blend.
If the scene has changed too much (trees blowing, waves, people or cars moving, etc.
between the images), especially at or near the "seams" of the blend, it will make the blend more difficult.</li>
</ol>
<p>
If you have only one image that needs exposure adjustment, you might look at using the "digital" neutral density filter or the contrast masking technique.
If you have only one image that needs exposure adjustment, you might look at using the "digital"
neutral density filter or the contrast masking technique.
<br />
Giving credit where credit is due: I did not come up with this method. I adapted it for The GIMP from a Photoshop tutorial on the luminous-landscape.com
Giving credit where credit is due: I did not come up with this method.
I adapted it for The GIMP from a Photoshop tutorial on the luminous-landscape.com
photography web site (great web site BTW, I recommend it).
</p>
<h2>The Procedure</h2>
<p>
The basic technique is to create a layer above the image that contains the other exposure of the same scene. Finally, we apply a layer mask to the this
The basic technique is to create a layer above the image that contains
the other exposure of the same scene. Finally, we apply a layer mask to the this
layer which makes parts of the image transparent that we want to show through from below.
</p>
......@@ -42,7 +47,8 @@
<img src="image-original-dark.jpg" alt=""/>
</p>
<p>
Here are the two exposures, loaded into the GIMP. I am going to sandwich these on different layers and then combine them with a layer mask.
Here are the two exposures, loaded into the GIMP. I am going to sandwich these
on different layers and then combine them with a layer mask.
</p>
<h2>Step 2</h2>
......@@ -56,7 +62,8 @@
The reason is because I hand-held the shots, and they are far from aligned. I'm going to have to move the bottom image until the arch is
aligned as best I can get it. Also, the top image is the composition I want anyway, and I'll have less painting to do that way.
<br /><br />
Go the image that is going to be on the bottom. Open the Layers dialog (<kbd>Ctrl+L</kbd>) and click on the new layer button (<img src="newlayer.jpg" alt=""/>) to create a new layer.
Go the image that is going to be on the bottom. Open the Layers dialog (<kbd>Ctrl+L</kbd>) and
click on the new layer button (<img src="newlayer.jpg" alt=""/>) to create a new layer.
</p>
<h2>Step 3</h2>
......@@ -65,8 +72,10 @@
<img src="layers4.jpg" alt=""/>
</p>
<p>
Go to the image that is going to be on top. Select all and copy (<kbd>Ctrl+A</kbd> then <kbd>Ctrl+C</kbd>). In the Layers dialog, make sure the new layer is selected,
then go to the bottom image window and paste (<kbd>Ctrl+V</kbd>). In the Layers dialog, click on the anchor button (<img src="anchor.jpg" alt=""/>) to anchor the floating image.
Go to the image that is going to be on top. Select all and copy (<kbd>Ctrl+A</kbd> then
<kbd>Ctrl+C</kbd>). In the Layers dialog, make sure the new layer is selected,
then go to the bottom image window and paste (<kbd>Ctrl+V</kbd>). In the Layers dialog,
click on the anchor button (<img src="anchor.jpg" alt=""/>) to anchor the floating image.
</p>
<h2>Step 4</h2>
......@@ -103,7 +112,8 @@
<img src="layers7.jpg" alt=""/>
</p>
<p>
In the Layers dialog, right-click on the upper layer and select Add Layer Mask. In the Add Mask Options dialog, select White (Full Opacity) and click OK.
In the Layers dialog, right-click on the upper layer and select Add Layer Mask.
In the Add Mask Options dialog, select White (Full Opacity) and click OK.
</p>
<h2>Step 7</h2>
......@@ -115,7 +125,8 @@
Now I want to paint black (transparency) onto the layer mask wherever I want the lower image to show through.
<br />
To minimize painting time, use the hand-select ("lasso"<img src="lasso.jpg" alt=""/> ) tool to select a large, hand-drawn region just
inside all the borders of the area you want to paint, as shown at right. Then using the fill tool (<img src="fill.jpg" alt=""/>) fill the selection with black.
inside all the borders of the area you want to paint, as shown at right.
Then using the fill tool (<img src="fill.jpg" alt=""/>) fill the selection with black.
</p>
<h2>Step 8</h2>
......@@ -124,8 +135,9 @@
<img src="image-paint1.jpg" alt=""/>
</p>
<p>
Next, I select a large opaque brush from the Brushes dialog (Dialogs/Brushes), select the Paint tool (<img src="paint.jpg" alt=""/>)
and begin painting into the mask close to the boundaries of the blend.
Next, I select a large opaque brush from the Brushes dialog (Dialogs/Brushes),
select the Paint tool (<img src="paint.jpg" alt=""/>) and begin painting into
the mask close to the boundaries of the blend.
<br /><br />
Notice that I still have the opacity cranked down on the upper layer so that I can see both layers.
</p>
......@@ -153,17 +165,22 @@
<p>
Now the most painstaking part: blending the seams. This is a little tricky due to the different tonalities of the two exposures.
<br />
For blending work, the Clone (<img src="clone.jpg" alt=""/>), Smudge (<img src="smudge.jpg" alt=""/>), Airbrush (<img src="airbrush.jpg" alt=""/>)
For blending work,
the Clone (<img src="clone.jpg" alt=""/>),
Smudge (<img src="smudge.jpg" alt=""/>),
Airbrush (<img src="airbrush.jpg" alt=""/>)
and Blur (<img src="convolve.jpg" alt=""/>) are my tools of choice.
</p>
<p>
Since I'm not sure if these tools have the ability to work across layers (as they do in Photoshop), I duplicate the image (<kbd>Ctrl+D</kbd>) and flatten the duplicate
(<span class="filter">&lt;Image&gt;Layers-&gt;Flatten Image</span>) and work on it. This has the additional benefit that if I ever mess up the blending job too badly I can
Since I'm not sure if these tools have the ability to work across layers
(as they do in Photoshop), I duplicate the image (<kbd>Ctrl+D</kbd>) and flatten the duplicate
(<span class="filter">&lt;Image&gt; Layers -&gt; Flatten Image</span>) and work on it.
This has the additional benefit that if I ever mess up the blending job too badly I can
always easily start over at this step.
</p>
<p>
<b>Note:</b> see <a href="/tutorials/Photo_Edit/Blown_Out_Highlights/">this tutorial on correcting blown out highlights</a> for another example of using these tools
for blending and some useful tips on their use.
<b>Note:</b> see <a href="/tutorials/Photo_Edit/Blown_Out_Highlights/">this tutorial on correcting blown out highlights</a> for
another example of using these tools for blending and some useful tips on their use.
</p>
<p>
Here I've used primarily clone and a touch of smudge to blend the seams of the two exposures. I didn't do a very thorough job with this image,
......@@ -179,7 +196,8 @@
<img src="image-finished.jpg" alt=""/>
</p>
<p>
Finished. The image still has some problems with blown out highlights in the sunlight of the rock face. It is also a little too dark in the foreground shadow.
Finished. The image still has some problems with blown out highlights in the sunlight of the rock face.
It is also a little too dark in the foreground shadow.
</p>
<h2>Further Reading on Blending Exposures</h2>
......
......@@ -13,17 +13,21 @@
<img src="after.jpg" alt=""/>
</p>
<p>
In this tutorial I'll show you how to salvage an image that has blown out highlights. This is a problem that is familiar to photographers shooting transparency film,
which has an effective contrast range of about 5 stops. If you are not careful with your exposure you can easily lose all detail in your highlight areas,
In this tutorial I'll show you how to salvage an image that has blown out highlights.
This is a problem that is familiar to photographers shooting transparency film,
which has an effective contrast range of about 5 stops. If you are not careful
with your exposure you can easily lose all detail in your highlight areas,
with no way to get it back: they "blow out" to clear (white).
<br /><br />
Many digital cameras have similar issues, especially consumer level ones. With these kinds of cameras it is worth paying attention to the old adage: "expose for the highlights".
Many digital cameras have similar issues, especially consumer level ones.
With these kinds of cameras it is worth paying attention to the old adage: "expose for the highlights".
I find that if I treat my digital camera as if I were shooting slide film the exposure rules are about the same.
</p>
<h2>The Procedure</h2>
<p>
The basic technique is to graft matching areas of the image into the burned out parts using the clone tool and then to use several additional tools to blend the seams of the cloned areas.
The basic technique is to graft matching areas of the image into the burned out parts
using the clone tool and then to use several additional tools to blend the seams of the cloned areas.
</p>
<h2>Step 1</h2>
......@@ -33,11 +37,14 @@
<p>
Here is the original image.
<br />
I saw my cat go up into a lemon tree. Thinking there might be an interesting shot there, I grabbed the camera and shot him from several angles,
including this shot through a hole in the foliage. When I saw the image later on the monitor I realized what a nice natural three-dimensional frame I had.
I saw my cat go up into a lemon tree. Thinking there might be an interesting shot there,
I grabbed the camera and shot him from several angles,
including this shot through a hole in the foliage. When I saw the image later on the
monitor I realized what a nice natural three-dimensional frame I had.
<br /><br />
The camera was set on automatic exposure. While it did a great job of exposing for the dark cat in the shade of the tree,
there are several spots where specular reflections of the bright sunshine overhead blew out. The worst and most noticable is the one off of the leaf at the top of the image.
there are several spots where specular reflections of the bright sunshine overhead blew out.
The worst and most noticable is the one off of the leaf at the top of the image.
There are some less objectionable, but bothersome burned out areas to the lower right of the cat's face.
<br /><br />
Great image...could I rescue it?
......@@ -59,11 +66,13 @@
<img src="threshold-image.jpg" alt=""/>
</p>
<p>
The first step is to create a channel mask to be able to mask out parts of the image we don't want to affect. I'll use this for the main "pixel graft".
The first step is to create a channel mask to be able to mask out
parts of the image we don't want to affect. I'll use this for the main "pixel graft".
<br />
Duplicate the original image (<span class="filter">&lt;Image&gt;Image-&gt;Duplicate</span> or <kbd>Ctrl+D</kbd>).
Duplicate the original image (<span class="filter">&lt;Image&gt; Image -&gt; Duplicate</span> or <kbd>Ctrl+D</kbd>).
<br />
In the duplicate, select <span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Threshold</span>. In the threshold dialog box, drag to select the very right
In the duplicate, select <span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Threshold</span>.
In the threshold dialog box, drag to select the very right
(extreme highlights) portion of the histogram. Alternatively, you can type in the lower bound, as I did here (250).
<br /><br />
This causes all the pixels in the image from 250-255 to go white and all the others to go black.
......@@ -79,7 +88,8 @@
<img src="image-channel.jpg" alt=""/>
</p>
<p>
Go back to the original image, and bring up the Layers and Channels dialog (<span class="filter">&lt;Image&gt;Layers-&gt;Layers, Channels &amp; Paths</span>, or <kbd>Ctrl+L</kbd>).
Go back to the original image, and bring up the Layers and Channels dialog
(<span class="filter">&lt;Image&gt; Layers -&gt; Layers, Channels &amp; Paths</span>, or <kbd>Ctrl+L</kbd>).
Click on the Channels tab and add a new channel by clicking on the new channel button.
</p>
......@@ -93,9 +103,10 @@
<img src="layers2.jpg" alt=""/>
</p>
<p>
Go back to the threshold image, <span class="filter">&lt;Image&gt;Select-&gt;All</span> (Ctrl+A) and <span class="filter">&lt;Image&gt;Edit-&gt;Copy</span> (<kbd>Ctrl+C</kbd>).
Go back to the threshold image, <span class="filter">&lt;Image&gt; Select -&gt; All</span>
(<kbd>Ctrl+A</kbd>) and <span class="filter">&lt;Image&gt; Edit -&gt; Copy</span> (<kbd>Ctrl+C</kbd>).
<br />
<span class="filter">&lt;Image&gt;Edit-&gt;Paste</span> it into the original image (it should go into the new channel).
<span class="filter">&lt;Image&gt; Edit -&gt; Paste</span> it into the original image (it should go into the new channel).
<br />
Click on the Layers tab and anchor the floating selection.
<br />
......@@ -111,9 +122,11 @@
Click on the Channels tab again, and right click on the new channel and select Channel to Selection (<kbd>Ctrl+S</kbd>).
You may want to also click on the eye beside the channel to turn off visibility of the channel.
<br /><br />
Now feather the selection (<span class="filter">&lt;Image&gt;Select-&gt;Feather</span>). I used a value of 15 pixels or so in this case.
Now feather the selection (<span class="filter">&lt;Image&gt; Select -&gt; Feather</span>).
I used a value of 15 pixels or so in this case.
<br />
Finally (important!), click back on the Layers tab and select the Background layer, so the selection and further operations will apply to the image and not the channel mask.
Finally (important!), click back on the Layers tab and select the Background layer,
so the selection and further operations will apply to the image and not the channel mask.
</p>
<h2>Step 7</h2>
......@@ -129,13 +142,15 @@
A description of how to use this tool is beyond the scope of this document
(see the <a href="http://gimp-savvy.com/BOOK/index.html">GIMP savvy</a> to find out more about this tool).
<br /><br />
I cloned from the light part of the leaf just beyond the dark band to the right of the blown out area. This gave me a similar light-dark-light transition.
You can see the clone tool options and the brush (<span class="filter">&lt;Image&gt;Dialogs-&gt;Brushes</span>) I selected (at right).
I cloned from the light part of the leaf just beyond the dark band to the right of the blown out area.
This gave me a similar light-dark-light transition.
You can see the clone tool options and the brush
(<span class="filter">&lt;Image&gt; Dialogs -&gt; Brushes</span>) I selected (at right).
<br />
Zoom in and clone until you have the area filled with a realistic facimile of the missing detail. Most likely it will have a noticable transition around the edges.
That's OK, we'll fix that up next.
Zoom in and clone until you have the area filled with a realistic facimile of the missing detail.
Most likely it will have a noticable transition around the edges. That's OK, we'll fix that up next.
<br />
<span class="filter">&lt;Image&gt;Select-&gt;None</span> and zoom out to inspect your work.
<span class="filter">&lt;Image&gt; Select -&gt; None</span> and zoom out to inspect your work.
</p>
<h2>Step 8</h2>
......@@ -158,7 +173,8 @@
<img src="image5.jpg" alt=""/>
</p>
<p>
This step is where the most difficult work occurs. I must by necessity abbreviate this step, since it involves iterations of applying the following tools:
This step is where the most difficult work occurs. I must by necessity abbreviate this step,
since it involves iterations of applying the following tools:
</p>
<ul>
<li><img src="smudge.jpg" alt=""/> smudge</li>
......@@ -176,7 +192,8 @@
</p>
<ul>
<li>Make small changes so you can undo easily without having to redo a lot of work.</li>
<li>Experiment with the tool options, especially opacity, rate and pressure (double-click on a tool to see the tool options). Some examples I used here are shown at right.</li>
<li>Experiment with the tool options, especially opacity, rate and pressure
(double-click on a tool to see the tool options). Some examples I used here are shown at right.</li>
<li>Vary your brushes! You generally want a nice feathered edge for smoothing seams. Some examples I used here are shown at right.</li>
<li>When using the airbrush, use the color picker first to sample a pixel. I average a pixel value as shown in the color picker options, right.</li>
<li>Periodically, zoom in and out to examine your work. The zoom keys are incredibly handy for this ("=" key to zoom in, "-" key to zoom out).
......
......@@ -62,9 +62,11 @@
<p>
In the Layers dialog, select the Blur Overlay layer. In the "Mode" drop-down box, select "Overlay".
<br />
Now go back to the image window and apply a Levels (<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Levels</span>) or Curves
(<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Curves</span>)
and adjust it until the overall image has the proper brightness. You'll usually find it necessary to adjust the gamma slider (middle slider in Levels) down.
Now go back to the image window and apply a Levels
(<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Levels</span>) or Curves
(<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Curves</span>)
and adjust it until the overall image has the proper brightness.
You'll usually find it necessary to adjust the gamma slider (middle slider in Levels) down.
You are only adjusting the upper layer, but you are viewing the cumulative effect of the layer blend.
<br /><br />
<b>Tip:</b> If you don't get a good effect with Overlay mode, try Multiply mode (you can even change this while the Levels dialog is active).
......@@ -79,7 +81,8 @@
<img src="image-overlay-blur.jpg" alt=""/>
</p>
<p>
Go back to the image window and right click, selecting <span class="filter">&lt;Image&gt;Filters-&gt;Blur-&gt;Gaussian Blur</span>.
Go back to the image window and right click,
selecting <span class="filter">&lt;Image&gt; Filters -&gt; Blur -&gt; Gaussian Blur</span>.
You will need to experiment to find the best value, but typically a value between 10 and 30 will do nicely.
<br /><br />
Voila! If you don't like the effect, you can undo the blur (<kbd>Ctrl+Z</kbd>) and redo it (<kbd>Shift+Alt+F</kbd>) with a different value.
......@@ -90,9 +93,11 @@
<div class="subtitle">Tip: Protecting Highlights with a Layer Mask</div>
<p>
Although I like the effect, there is one problem with this technique and that is that it also increases contrast: the shadows get darker and the highlights get lighter.
Although I like the effect, there is one problem with this technique and that is that it also increases contrast:
the shadows get darker and the highlights get lighter.
<br />
You might be able to apply a contrast mask to counteract this effect, but in most cases it is the highlights that are the most troublesome in that they have lost detail.
You might be able to apply a contrast mask to counteract this effect,
but in most cases it is the highlights that are the most troublesome in that they have lost detail.
Fortunately we can apply a simple extension to the above technique to protect the highlights.
</p>
......@@ -103,7 +108,7 @@
<p>
Duplicate the image (<kbd>Ctrl+D</kbd>).
<br />
Flatten the duplicate (<span class="filter">&lt;Image&gt;Layers-&gt;Flatten Image</span>).
Flatten the duplicate (<span class="filter">&lt;Image&gt; Layers -&gt; Flatten Image</span>).
</p>
<h2>Step 6</h2>
......@@ -112,10 +117,11 @@
<img src="image-threshold.jpg" alt=""/>
</p>
<p>
In the duplicate, run a threshold filter (<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Threshold</span>).
In the duplicate, run a threshold filter (<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Threshold</span>).
<br />
In the threshold histogram, click and drag to the right to select all the pixels at the upper end of the scale.
Retry or adjust the selection using the number controls in the dialog box until the display shows most of the pixels you want to preserve as white and all the rest black.
Retry or adjust the selection using the number controls in the dialog box until the display shows
most of the pixels you want to preserve as white and all the rest black.
<br />
You only need to approximate this, since we're going to clean up the mask anyway.
</p>
......@@ -129,12 +135,15 @@
<img src="image-threshold-blur.jpg" alt=""/>
</p>
<p>
To clean up the mask, I switched to the paintbrush (<img src="paint.jpg" alt=""/>), hit "x" in the mask image to switch the foreground and background colors (Black/White to White/Black),
selected a nice opaque brush in the Brushes dialog and painted the few pixels of the sky white that hadn't been turned white (the darkest parts of the clouds).
To clean up the mask, I switched to the paintbrush (<img src="paint.jpg" alt=""/>),
hit "x" in the mask image to switch the foreground and background colors (Black/White to White/Black),
selected a nice opaque brush in the Brushes dialog and painted the few pixels of the sky white that hadn't
been turned white (the darkest parts of the clouds).
<br /><br />
Now the black parts. I switched the fg/bg colors back to (Black/White). I could have painted black all over the lake, but I had a faster idea in mind. I used the marquee
selection tool (<img src="selectrect.jpg" alt=""/>) to select the whole area and then using the fill tool (<img src="fill.jpg" alt=""/>) I just clicked in the selection
to fill it black in one fell swoop.
Now the black parts. I switched the fg/bg colors back to (Black/White).
I could have painted black all over the lake, but I had a faster idea in mind. I used the marquee
selection tool (<img src="selectrect.jpg" alt=""/>) to select the whole area and then using the
fill tool (<img src="fill.jpg" alt=""/>) I just clicked in the selection to fill it black in one fell swoop.
<br /><br />
I then "feathered" the mask so that it will blend the layers without a harsh transition by applying a 6 pixel gaussian blur to the mask.
</p>
......@@ -144,8 +153,9 @@
<img src="image-threshold-blur-invert.jpg" alt=""/>
</p>
<p>
Invert the mask (<span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Invert</span>), so that the white parts correspond to the parts of
the combined layers that you want to keep and the black parts correspond to the parts that should only reflect the original image (the highlights).
Invert the mask (<span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Invert</span>),
so that the white parts correspond to the parts of the combined layers that you want to keep
and the black parts correspond to the parts that should only reflect the original image (the highlights).
</p>
<h2>Step 9</h2>
......@@ -162,10 +172,12 @@
<br />
Right-click on the Blur Overlay layer and select Add Layer Mask. In the Add Mask Options dialog, select White (Full Opacity) and click OK.
<br />
Now go back to the blurred threshold image, select all and copy (<kbd>Ctrl+A</kbd> then <kbd>Ctrl+C</kbd>). Go back to the overlay blur image and paste (<kbd>Ctrl+V</kbd>).
Now go back to the blurred threshold image, select all and copy
(<kbd>Ctrl+A</kbd> then <kbd>Ctrl+C</kbd>). Go back to the overlay blur image and paste (<kbd>Ctrl+V</kbd>).
Go to the Layers dialog and click the anchor button (<img src="anchor.jpg" alt=""/>) to anchor the mask.
<br /><br />
<b>Tip:</b> <kbd>Ctrl-click</kbd> on the layer mask icon in the Layers dialog to toggle the effect of the layer mask to compare the image with and without the highlight mask.
<b>Tip:</b> <kbd>Ctrl-click</kbd> on the layer mask icon in the Layers dialog to toggle the effect of
the layer mask to compare the image with and without the highlight mask.
</p>
<h2>Step 10</h2>
......
......@@ -12,7 +12,7 @@
Since Gimp is an image manipulation program and not a painting program it doesn't include tools to draw shapes like squares and circles.
However this doesn't mean you can paint them, in fact there are some interesting options regarding this subject when it comes to the gimp.
The solution is to use the selection stroking capabilities of the Gimp. This option can be accesed on the image menu (right button click
on the image), by going to <span class="filter">&lt;Image&gt;Edit-&gt;Stroke</span>.
on the image), by going to <span class="filter">&lt;Image&gt; Edit -&gt; Stroke</span>.
</p>
<h2>Step 1</h2>
......@@ -47,7 +47,8 @@
<img src="img17_result.png" alt=""/>
</p>
<p>
When all the options are selected you can finally click on <span class="filter">&lt;Image&gt;Edit-&gt;Stroke</span>. Using a small brush and selecting a blue color here is
When all the options are selected you can finally click on <span class="filter">&lt;Image&gt; Edit -&gt; Stroke</span>.
Using a small brush and selecting a blue color here is
the result for the selection made above:
</p>
......
......@@ -47,8 +47,10 @@
<img src="menu.png" alt=""/>
</p>
<p>
The first step is to activate the color to alpha plug-in. Its menu location is <span class="filter">&lt;image&gt;Filters-&gt;Colors-&gt;Color To Alpha</span>,
where &lt;image&gt; means to right click on the image. If its grayed-out, it means that you have an indexed image. If its not there, upgrade your gimp to 1.2.x.
The first step is to activate the color to alpha plug-in. Its menu location is
<span class="filter">&lt;image&gt; Filters -&gt; Colors -&gt; Color To Alpha</span>,
where &lt;image&gt; means to right click on the image. If its grayed-out,
it means that you have an indexed image. If its not there, upgrade your gimp to 1.2.x.
</p>
<h2>Step 2</h2>
......
......@@ -9,8 +9,10 @@
<img src="img1_initial.jpg" alt=""/>
</p>
<p>
Many times you have an image with a colored background, like the one below and you want to take out the background to use the image's subject in a composition.
With gimp there are many ways to achieve this, one of which is using a plug-in specifically designed for this: Changing Background Color 1.
Many times you have an image with a colored background, like the one below and you want to take
out the background to use the image's subject in a composition.
With gimp there are many ways to achieve this, one of which is
using a plug-in specifically designed for this: <a href="/tutorials/Changing_Background_Color_1/">Changing Background Color 1</a>.
</p>
<h2>Step 1</h2>
......@@ -18,8 +20,10 @@
<img src="img3_step1.png" alt=""/>
</p>
<p>
In this tutorial I explore the select by color option to remove a particular color from the image. The first step, after you have loaded the image of course,
is to click on the image with the right mouse button, and choose the option <span class="filter">&lt;Image&gt;Select-&gt;By Color</span> as seen above:
In this tutorial I explore the select by color option to remove a particular color from the image.
The first step, after you have loaded the image of course,
is to click on the image with the right mouse button, and choose the option
<span class="filter">&lt;Image&gt; Select -&gt; By Color</span> as seen above:
</p>
<h2>Step 2</h2>
......@@ -27,11 +31,16 @@
<img src="img4_step2.png" alt=""/>
</p>
<p>
After choosing that option a dialog window will appear. This window shows several options. The black square on the left side shows the current selection.
Anything that appears white is selected, anything that is black is not. When you strart using the dialog you will see what this means. On the right side
there are two options we will consider for the moment. The first one is the Selection Mode. We will use the add option, which means any color we click on
will be added to the selection. The other setting is the Fuzziness Threshold. When you click on a color, the higher this setting is, the more similar colors
to the one you clicked on will be selected. You can start by using the default setting and increasing it if you need to add more colors faster, or decrease
After choosing that option a dialog window will appear. This window shows several options.
The black square on the left side shows the current selection.
Anything that appears white is selected, anything that is black is not.
When you strart using the dialog you will see what this means. On the right side
there are two options we will consider for the moment. The first one is the Selection Mode.
We will use the add option, which means any color we click on
will be added to the selection. The other setting is the Fuzziness Threshold.
When you click on a color, the higher this setting is, the more similar colors
to the one you clicked on will be selected. You can start by using the default
setting and increasing it if you need to add more colors faster, or decrease
it if you're selecting more then you want. Select by color dialog
</p>
......@@ -58,7 +67,7 @@
<img src="img7_step5.png" alt=""/>
</p>
<p>
With the selection complete and with an alpha channel just choose from the image menu <span class="filter">&lt;Image&gt;Edit-&gt;Clear</span>,
With the selection complete and with an alpha channel just choose from the image menu <span class="filter">&lt;Image&gt; Edit -&gt; Clear</span>,
and the image background will be gone.
</p>
......
......@@ -44,10 +44,12 @@
Here is what I get if I use the standard mode change to grayscale from RGB.
</p>
<p>
Duplicate the original image (<kbd>Ctrl+D</kbd>) and right-click on the copy. Select <span class="filter">&lt;Image&gt;Image-&gt;Mode-&gt;Grayscale</span>.
Duplicate the original image (<kbd>Ctrl+D</kbd>) and right-click on the copy.
Select <span class="filter">&lt;Image&gt; Image -&gt; Mode -&gt; Grayscale</span>.
I don't know how this conversion works in the GIMP, but I have read that Photoshop uses a standard mix of the RGB channels for
their grayscale conversion: RED=30%, GREEN=59% and BLUE=11%. Supposedly this mix accounts for the eye's sensitivity to different colors.
This formula does a pretty nice job in the general case, but some images do not work as well with it, particularly if the green channel component is not strong.
This formula does a pretty nice job in the general case, but some images do not work as well with it,
particularly if the green channel component is not strong.
</p>
<p>
I suspect the GIMP uses a similar formula. My experiments with the Channel Mixer (more on this below) support this.
......@@ -60,11 +62,12 @@
</p>
<p>
Here is what I get if I use desaturate instead. Duplicate the original image (<kbd>Ctrl+D</kbd>) and right-click on the copy.
Select <span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Desaturate</span>. Unlike the grayscale mode change above,
Select <span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Desaturate</span>. Unlike the grayscale mode change above,
the channels are not remixed in different percentages, so we should expect different results.
</p>
<p>
The result is visually different; note the increased contrast in the scales. Also, compare the 100% zoom views at right and in the previous grayscale example.
The result is visually different; note the increased contrast in the scales.
Also, compare the 100% zoom views at right and in the previous grayscale example.
You can see a lot more noise in the desaturated zoomed view (examine the blurred area below the spikes).
The reason is that we are getting more blue and red channel noise, whereas in the grayscale mode change operation
the algorithm is giving us a remix of 60% of the clean, detailed green channel.
......@@ -88,7 +91,8 @@
</p>
<p>
A third method is to consider the red/green/blue channels of the image. Each one can be represented as an independent grayscale image.
Right-click on the original image and select <span class="filter">&lt;Image&gt;Image-&gt;Mode-&gt;Decompose</span>. Select the RGB option and click OK.
Right-click on the original image and select <span class="filter">&lt;Image&gt; Image -&gt; Mode -&gt; Decompose</span>.
Select the RGB option and click OK.
</p>
<p>
Here you can see the three channels: red (top), green (middle) and blue (bottom). You can see that the red channel contains most
......@@ -106,8 +110,10 @@
<img src="image-value-481x397.jpg" alt=""/>
</p>
<p>
Another possibility is to decompose to Hue/Saturation/Value components and consider the Value image (the other two are not usually useful for this purpose).
Right-click on the original image and select <span class="filter">&lt;Image&gt;Image-&gt;Mode-&gt;Decompose</span>. Select the HSV option and click OK.
Another possibility is to decompose to Hue/Saturation/Value components and consider the Value image
(the other two are not usually useful for this purpose).
Right-click on the original image and select <span class="filter">&lt;Image&gt; Image -&gt; Mode -&gt; Decompose</span>.
Select the HSV option and click OK.
</p>
<h2><a name="decomposeLAB">Via Decompose LAB</a></h2>
......@@ -151,7 +157,7 @@
</p>
<p>
The final technique is the Channel Mixer filter. Right-click on the original image and select
<span class="filter">&lt;Image&gt;Filters-&gt;Color-&gt;Channel Mixer</span>.
<span class="filter">&lt;Image&gt; Filters -&gt; Color -&gt; Channel Mixer</span>.
</p>
<p>
You'll get a dialog box like the one at right. Click the checkbox that says Monochrome. Make sure the preview checkbox is also checked.
......
......@@ -67,7 +67,8 @@
<img src="image2.jpg" alt=""/>
</p>
<p>
Select the Contrast Mask layer. Go to the image window and right-click, selecting <span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Desaturate</span>.
Select the Contrast Mask layer. Go to the image window and right-click,
selecting <span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Desaturate</span>.
The image should look B&amp;W.
</p>
......@@ -76,7 +77,8 @@
<img src="image3.jpg" alt=""/>
</p>
<p>
Right-click and select <span class="filter">&lt;Image&gt;Image-&gt;Colors-&gt;Invert</span>. You now have a B&amp;W negative image of your original.
Right-click and select <span class="filter">&lt;Image&gt; Image -&gt; Colors -&gt; Invert</span>.
You now have a B&amp;W negative image of your original.
We're going to combine this with the original (light with dark, dark with light) to reduce the overall contrast.
</p>
......@@ -97,7 +99,7 @@
<img src="image5.jpg" alt=""/>
</p>
<p>
Go back to the image window and right click, selecting <span class="filter">&lt;Image&gt;Filters-&gt;Blur-&gt;Gaussian Blur</span>.
Go back to the image window and right click, selecting <span class="filter">&lt;Image&gt; Filters -&gt; Blur -&gt; Gaussian Blur</span>.
You will need to experiment to find the best value,
but typically a value between 10 and 30 will do nicely. After blurring the contrast mask the overall image should now look much sharper.
<br /><br />
......@@ -137,7 +139,7 @@
</p>
<p>
You'll have to flatten the image if you are saving it to a typical image format like TIFF or JPEG (but not if you are saving to the GIMP's native XCF format).
To do that, right-click on the image and select <span class="filter">&lt;Image&gt;Layers-&gt;Flatten Image</span>.
To do that, right-click on the image and select <span class="filter">&lt;Image&gt; Layers -&gt; Flatten Image</span>.
</p>
<h2>Fine Tuning</h2>
......
......@@ -49,25 +49,29 @@
<h2>Getting Started</h2>
<p>
When you're ready to start, run GIMP by selecting <span class="filter">Applications-&gt;Graphics-&gt;GIMP</span> Image Editor from your menu panel,
or typing <b>gimp</b> at the command line. If you haven't used GIMP before, the default window layout may be a little confusing.
It's a lot like Photoshop and other similar applications, in that it uses a large number of dialogs. Select items from the
<span class="filter">File-&gt;Dialogs</span> menu to choose which dialog windows you'd like to have open and which ones you'd like to have closed.
For icon work, you may find it most convenient to use the main window, plus the palette and layers dialogs, and of course the actual image you're working on.
When you're ready to start, run GIMP by selecting <span class="filter">Applications -&gt; Graphics -&gt; GIMP</span>
Image Editor from your menu panel, or typing <b>gimp</b> at the command line. If you haven't used GIMP before,
the default window layout may be a little confusing. It's a lot like Photoshop and other similar applications,
in that it uses a large number of dialogs. Select items from the
<span class="filter">File -&gt; Dialogs</span> menu to choose which dialog windows you'd like to have open and which ones you'd like to have closed.
For icon work, you may find it most convenient to use the main window,
plus the palette and layers dialogs, and of course the actual image you're working on.
</p>
<p>
To create a new image file, press <kbd>Ctrl+N</kbd>. Select a 48x48 pixel image, the standard Gnome icon size.
Because working on such a tiny pixmap requires a lot of detail, zoom in to work on a pixel-by-pixel level.
Try <i>8:1</i> magnification (<span class="filter">&lt;Image&gt;View-&gt;Zoom-&gt;8:1</span>).
Try <i>8:1</i> magnification (<span class="filter">&lt;Image&gt; View -&gt; Zoom -&gt; 8:1</span>).
</p>
<p>
At that magnification, however, you will begin to lose perspective. It's best to keep an additional window open with an unmagnified view,
so you can see what your icon will look like. To do that, choose <span class="filter">&lt;Image&gt;View-&gt;New view</span> from the image context menu
(the little arrow in the upper left side of the window). Use a <i>1:1</i> zoom on this view, so that you can paint at an <i>8:1</i> zoom and see the results immediately.
so you can see what your icon will look like. To do that, choose
<span class="filter">&lt;Image&gt; View -&gt; New view</span> from the image context menu
(the little arrow in the upper left side of the window). Use a <i>1:1</i> zoom on this view,
so that you can paint at an <i>8:1</i> zoom and see the results immediately.
</p>
<p>
Make sure to turn off the selection decorations on the <i>1:1</i> window. To do that, focus the window and press <kbd>Ctrl+T</kbd> or choose
<span class="filter">&lt;Image&gt;View-&gt;Toggle selection</span>.
<span class="filter">&lt;Image&gt; View -&gt; Toggle selection</span>.
</p>
<h2>A Few Tricks</h2>
......@@ -181,7 +185,8 @@
</p>
<p>
If you want to create horizontal monitor lines on the screen, you can use the interlace effect. To do so, create a new layer above the current one.
Render white horizontal lines with <span class="filter">&lt;Image&gt;Filters-&gt;Render-&gt;Pattern-&gt;Grid</span>. Make sure you set the layer mode to <i>Overlay</i>.
Render white horizontal lines with
<span class="filter">&lt;Image&gt; Filters -&gt; Render -&gt; Pattern -&gt; Grid</span>. Make sure you set the layer mode to <i>Overlay</i>.
</p>
<p class="images">
<img src="button.png" alt=""/>
......@@ -212,7 +217,8 @@
<p>
You can make almost any image, especially a small one, easier to understand by adding black object outlines to enhance contrast.
To do this, you'll use the opposite of technique you used to create the television silhouette with its outline. First,
right-click on the remote control layer and select <span class="filter">Layers-&gt;Alpha to selection</span>. Create a new empty layer below the remote control layer.
right-click on the remote control layer and select <span class="filter">Layers -&gt; Alpha to selection</span>.
Create a new empty layer below the remote control layer.
Increase the size of the selection by 1 pixel, and fill the selection with black.
</p>
<p class="images">
......@@ -244,7 +250,8 @@
<p>
For extra realism you can add a TV glow. Create a layer above the screen, but below the remote. Create a rectangular selection of the screen,
then increase its size by 6 pixels and fill it with blue. Now, shrink that selection by 3 pixels and fill with white.
Deselect the are with <kbd>Ctrl-Shift-A</kbd> and apply <span class="filter">&lt;Image&gt;Filter-&gt;Blur-&gt;Gaussian Blur RLE</span> by about 5 pixels.
Deselect the are with <kbd>Ctrl-Shift-A</kbd> and apply
<span class="filter">&lt;Image&gt; Filter -&gt; Blur -&gt; Gaussian Blur RLE</span> by about 5 pixels.
Now set the layer mode to <i>overlay</i>, creating the transparency effect.
</p>
......
......@@ -47,13 +47,14 @@
</p>
<p>
The last step is to save our brush as a GIMP picture brush. The extension of this kind of brush is .GIH. So right click on the image, then choose
<span class="filter">&lt;Image&gt;File-&gt;Save As....</span>
<span class="filter">&lt;Image&gt; File -&gt; Save As....</span>
Because all brushes resides in the /gimp/brushes folder go to that folder and type in a name for the brush. For our example, the brush was named HAPPY.GIH
<br />
Then Save As Pixmap Brush Pipe dialog will ask you how you want to save the image. Since we have 3 layers make sure we put 3 in the Ranks edit box.
You can also choose how you want the images to appear as you move the mouse aruond. In mose cases Random will do fine.