In this last Lesson i am introducing some tools basically useful in photography as complementary improvements. They act on bitmap image data. In general these tools have to do with transformations, noise reduction, and they remind what the good old photographers knew as retouching.
These tools are addressed rather for the advanced user, but in their basic use they can be used by a beginner as well. It will be important to use the GIMP's documentation on the topics in reference. After the 19 Lessons you must know how important it is to use the documentation!
The Clone Tool
The Clone Tool deserves your full attention in photography. It has significant hidden powers. It is typically used for local repairs in images, but it can be used more creatively. Those hidden powers emerge using it on different drawables, that is to say from one drawable to another drawable: a layer, a mask, a channel. Still more, it can be used on two drawables belonging to two different images. It even can copy data from a disabled drawable.
As seen in Lesson 13, the Clone Tool can be used with the option Alignment: Registered in the important process of variant selective masking.
Advanced hidden powers for the Clone Tool
As nicely explained in the documentation, there are two more smart ways to exploit the abilities of the Clone Tool:
- you can use it as "Filter Brush",
- you can imitate the Photoshop's "History Brush".
Advanced hidden powers II - avoiding local violence on bitmap data
The paint tools do not act on the whole layer/image, but locally on a part of it. This is related to their inherent ability which they are intended to offer. This is what they have been made for, period.
Sometimes you may find yourself in the following annoying situation. You have tried hard to save a problematic shot, using paint tools locally on specific problematic areas on your image. You finally save a usable JPG. You check this file, and your are surprised to see your image awfully spoiled in those heavily repaired areas. This is getting to your nerves!
Try to save your usable image as a lossless file, let us say a TIF. Now the image looks fine! Strange things happening! The explanation lies in the fact that the lossy compression of the JPG messes up the already "disturbed" frequencies after your heavy local editing.
Solution? Not guaranteed that you will solve your problem with your problematic shot, but chances are that you will have a better result with another approach. Do not paint directly on your layer with your paint tools, instead:
- duplicate the layer,
- in the new layer try to achieve the result you want not with the paint tools but with the color tools and acting on the whole layer, focusing only on the critical interesting areas and ignoring the rest,
- use the Clone Tool copying locally from the new layer with Alignment: Registered as a "filter brush".
The Healing Tool
It resembles the Clone Tool, being a smarter version of it intended for correcting small "defects". The difference is nicely and clearly explained in the documentation.
The Blur/Sharpen Tool
It is used to blur either sharpen bitmap data locally. In the documentation, note the tip for using it as a "filter brush".
The Smudge Tool
Another "strange" tool which can do wonders in the hand of an experienced digital artist, with a drawing tablet. Experienced users use it in their workflow for local editing on secondary drawables and especially masks.
The Dodge/Burn Tool
You can use this to locally lighten either darken bitmap image data. This tool has interesting options as well, with the addition of selectively acting on the shadows, on the midtones or on the highlights. Try it in action to understand the subtle difference between the two options of opacity and exposure.
The Scale Tool
To change the size of the whole image, you use the command Image > Scale Image... explained in Lesson 3. To change the size of an item -a layer, a selection, or a path- you use the Scale Tool. After what you have learnt, it will be very easy to understand the options.
The Blend Tool and the Gradients
Another little miracle in the GIMP. The documentation says it like this: "There are an astonishing number of things you can do with this tool, and the possibilities may seem a bit overwhelming at first". In its simplest use, it fills a layer (or selection) with a color gradient, but please do not believe me if i tell you that it can do many more things until you check the documentation.
Special transformation tools
There is a group of some rather unusual tools: the Shear Tool, the Perspective Tool, the Flip Tool, the Cage Transform Tool. The thing i would like to note is that you should better have a powerful computer if you want to use them on big files.
Noise reduction
Like it or not, you will face it. Digital noise is a potential problem in low light conditions.
You can find G'MIC here. It is a free library with some very useful filters and other goodies. Yes, very useful! Installing this thing as a GIMP plugin may be not an extremely easy thing (you can find instructions though) but it is worth the pain. Once i tried to install this plugin in a portable GIMP installation, and it worked nicely. At the time of this writing (version v2.2.2, 2018) the anisotropic smoothing filter resides under the filter group Repair. It has other methods as well. It also has many other useful filters and stuff for many tasks. It actually is a software bundle by itself. One more nice surprise of free software. Thanks!
Thanks to the people of GIMP, thanks to You for attending this School, thanks to everyone who offers just a bit of himself, sometimes a bit is enough.-
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