Terragen
images colour correction and other adjustments |
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| You have rendered you picture in Terragen, you have saved
it, then you look at it and say to yourself “This looks good, but
I know there is some room for improvement, but not in Terragen”. Then
it’s time for a little correction, which can have a great impact on
the way the image looks. It can either improve it or be totally messed up. |
The aim of this text is to help you with some very basic notions and
“methods” which might become handy at the time of making corrections
to the finished images. We are going to use Photoshop, but the same ideas
can be applied using any other software with similar capabilities.
The first method we're going to apply is a very simple one that gives
good results in most cases but no perfect control over all aspects of
the image.
The second method we're going to show you here might be a bit complicated
at first sight, but it gives a perfect control over all aspects of the
image. Usually, when you load your image in the editor and you adjust
aspects of the image (curves, contrast, colour correction, etc.) you affect
the entire image. That might not be very desirable in most of the cases,
since when we adjust the lighter parts of the image the darker ones are
also affected.
In order to avoid this we’re going to use some correction layers
used as masks.
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| Open the image in your editor. Usually TG images tend
to have an "overexposed" look to them, a bit too light all
over the image or, quite on the contrary, have very dark areas. Lighting
in Terragen is very hard to master, and sometimes we have to "sacrifice"
a bit of something in order to get what we desire. At the right we
have a strip of our image as it came out of TG (only cropped, resized
and converted to .jpg). Overall we can assume it lacks a bit of contrast
and that some adjustments could be done. |
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First method
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The curves dialog window. The arrow indicates
the "set white point" eyedropper tool. |
The threshold view — darkest areas.
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The layers window. |
Our adjusted image. |
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You have to create a curves adjustment layer (Choose "Layer
> New Adjustment Layer > Curves"). In the curves dialog
box you just have to decide which point of your image is the darkest
and which one is the lightest one. Now click on the "set white
point" eyedropper tool. Go into your image and click on one
of its lightest areas. A good way to find out which areas are really
darker or lighter is to use the "info" window; Watch the
RGB indicators, the closer they are to 256 (on all three channels)
the lighter the spot you are over is. On the other hand, as this
figures show numbers closer to 0 you are over a darker spot. This
is very useful when you have very small changes that your eye probably
won't see.
Another and very easy method for finding these two points is using
the threshold adjustment device. Choose "Image / Adjustment
/ Threshold". When you put the slider to the left, you only
see the darkest areas of your image. Put it to the right and you
only see the lightest areas. Then push "escape" on your
keyboard for exiting this device.
Go back to the curves window and click on the "set black point"
eyedropper tool. Go into your image and click on one of its darkest
areas. Click OK and it's over! You already have a big improvement
of the contrast in your image. The colors are brighter too.
You can also try starting with the black point and ending with the
white one. The results may be slightly different.
If your image contains spots of a neutral gray (again, you can
use the "info" window to guide yourself, as the RGB values
get close to 128 you'll know you are over a neutral gray area) you
might want to use the "set gray point" eyedropper tool
on the same curves window. Repeat the same procedure as with the
other two points, select the tool and click on a neutral gray area
of the image.
If you're not satisfied with the results, it's very simple to go
back to where you started correction by clicking the "Cancel"
(PS 7) or "Reset" (PS 6 or older) button.
In any case, if you find that the corrections are too strong, it's
easy to diminish the effect by playing with the "Opacity"
slider of the adjustment layer.
If, on the other hand, you feel the effect is not enough you can
duplicate this adjustment layer to further enhance the corrections.
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Second Method
In this second method we are going to generate three layers which will
adjust sections with light, midtones and darker areas respectively. By
doing so we can correct each part as we like without affecting the others.
Besides we we'll have perfect control on the way each correction acts,
since we will also be able to use the "opacity" slider in order
to affect the overall effect of each correction layer.
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| Go to the "selection" menu, "colour range" and select
"light" under the selection drop-down menu. This will select all
the lighter areas of our image. |
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Now go to the "layers" window, and create
a new curves adjustment layer (The red arrow shows where adjustment
layers are selected). Hit the "OK" button when the curves
dialog pops-up and repeat the same process with midtones and shades.
you should then have something similar to the image to the left (the
small brightness/contrast icons might be a "curve" icon,
depending on your photoshop version). Now we are ready to start adjusting
our image. |
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It is a bit harder to master colour correction using
this particular method, since it might sometimes be difficult to make
the three adjustment layers “work together”. You might have
to try several different attempts before actually getting the desired
result. But, as we have already said, you now have a lot more control
over what you are adjusting and how.
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A good way to have some idea of how the curves affect
each layer is using the channels. Select one of your curves layers
and then go to the channels window. You'll see that the mask channel
(2) is off by default,
if you turn it on you'll see the effect of that layer. |
| If you turn off the RGB channel (1
on the image above) you will be able to see the mask itself. Areas
in white are affected, while areas in black are left unaltered (once
again by the layer you have selected on the "layers" tab).
Using these two views you should be able to have a pretty good idea
of what's happening with each correction you make. |
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The curves might be tricky from time to time. The only
way to really know how they affect the image is by trial and error,
since every image is different. Draw different curves, try different
settings, and always do radically different attempts until you get
to the one that suits you best. You'll find out that after a few tests
you will have a much better knowledge of how each curve will affect
the image and the process will become very natural and fast. In the
image to the left you can see an example of a subtle curve we've used
for this example (lighter areas). |
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| All adjustments you are going to make are up to you and what you consider
the best for the particular image you've rendered, we are going to give
a little example of an adjustment we found “appropriate” for
this image and a few exaggerated examples just to make our point. |
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Original image |
Adjusted image. Changes are very
subtle, but we've managed to lighten the snow a bit, darken the
shades, and darken and lighten up parts of the midtones. |
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Of course it is quite possible to get some
very exaggerated results as well, some follow:
You have the power to do almost anything
to your image! |
| TIP: you can even
add some other correction layers for different colours. You could
select the greens and adjust them, or the blues and only touch up
the sky. The possibilities are endless! |
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| Remember you can use the "Opacity" slider to adjust how much
each adjustment layer affects the looks of the final image. |
| With this we end our "curves correction" section, but it is
NOT the end of it! We shall now review contrast, sharpness, resizing and
final save to .jpg file so you can share your images. |
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