Lesson 1 - Colours: Basic Techniques

[Goofy]

Note: This lesson is rather easy, so I recommend completing it soon so we can move on to the next one - the course is long.

Getting Started

Hi everyone and, one more time, welcome to GIMP Basics Course II!

Required material

• GIMP, a free image manipulation program
  
  • You should download either GIMP 2.6.12 or GIMP 2.8.0 Release Candidate 1. The newer version may make studying harder, though, as I have made the lessons with GIMP 2.6.11
• Access to an image hosting site (I highly recommend ImageShack)
• Extra brushes (more on this on Lesson 4)
• Optional: Extra fonts (you can find them on dafont for example)

The GIMP interface

This is a screenshot of the interface of GIMP version 2.6.11. I have marked the important parts of the image with colours and numbers.

Click to view content: 

• File: file operations, such like saving and printing options, can be found here
• Edit: some edit functions (including for example copying and pasting as well as GIMP preferences) are found here
• Select: this legend opens a few selection functions (grow/shrink selection etc.)
• View: edit view preferences
• Image: image operations (image autocropping, rescaling etc.) and several image properties can be found here
• Layer: layer functions and options (layer autocropping, rescaling etc.) are found here
  
  • At this point you may be wondering what a layer actually is. Well, layers are kind of "image levels" that you can put on top of each other. If you have a layer and another, non-transparent layer on top of it, you can't see what there is under the upper layer. So, layers are a little like images that have been put one upon the other. You can also edit layers' opacity and layer mode in the Layer menu (see below) - we'll learn more about this later on this lesson. You can basically create as many layers as you want (the only limit is the maximum file size you have set in your preferences)
• Colors: colour functions, tools and options; brightness, contrast, recolouring and all the likes
• Tools: a tab for selecting tools - by default this includes some tools that are not found in the Toolbox. I suggest using the Toolbox instead of this, however - especially when you have more experience. It's a lot quicker that way
• Filters: artistic effects plus countless automatic plug-in functions and such can be found under this legend. We'll be working with certain filters a lot during this course
• Windows: this can mainly be used for bringing up windows - so nothing very useful to know here if you ask me. You can also jump between different images opened in GIMP by using this tab
• Help: quite self-explanatory, yet this tab is not very helpful if you ask me. You won't need it anyways

Note that you can open several of the tabs mentioned above simply by right-clicking your image (that will open a quick menu where you can select the tab you want to open).

• 1. Layer menu: this menu shows you the layers of your image file. Most layer actions can be performed by right-clicking the layer. The topmost layer is also the topmost one in the layers menu (in the example picture above no layers can be seen, because I haven't any image file opened). By clicking on the eye next to the layer you can make it invisible (or make it visible again). This way you can like "temporarily delete" the layer - you can't see it, but it still is there.
• 2. Brush menu: the selection of brushes, gradients and patterns is displayed here. Click on a brush to select it
• 3. The Toolbox: the selection of the basic tools. I have customised my Toolbox options so I have more tools in my Toolbox than there are by default - changing the options is taught in my GIMP Basics Tutorial [link]
• 4. Tool options and details: here you can adjust the options and details for the tool you are using, such like scale, pressure or opacity
• 5. Colour & gradient window: Your selected foreground and background colours are displayed here, as well as the gradient you're using. To change the FG (the upper one) and BG (on the right of the FG colour) colours you have to click on either of them. Then a window with several sliders will pop up. By moving the sliders you can change the colour. To change the gradient, simply click on it and you'll see a selection of different gradients to choose from

Useful shortcuts

Here I have listed a few very useful shortcuts that will make your life easier...

• Ctrl + Z: undo
• Ctrl + Y: redo
• Ctrl + N: new image
• Ctrl + Shift + N: new layer
• Ctrl + S: save
• Ctrl + Shift + S: save as (you can change the name and file format of your image by using this option)
• Ctrl + A: select all (the whole image/layer)
• Ctrl + C: copy
• Ctrl + X: cut
• Ctrl + V: paste
• Ctrl + Shift + V: paste to a new image
• Ctrl + F: rerun the last plug-in (this contains mostly filters)
• Ctrl + Shift + F: reshow the window of the last used plug-in
• Ctrl (hold) + Scroll: zoom in/out (this is the most important of all!)

By using these you don't have to spend time jumping from window to window and menu to menu all the time. You'll learn them quite quickly, and after that using them gets more and more automatic.

Lesson 1 - Colours: Basic Techniques

On this lesson we'll study a very basic feature of GIMP - the colour functions. The concept of this lesson is very simple but important, so don't get fooled by that! The lessons will progressively get more difficult. In the end you should be able to make your own avatars, signatures, wallpapers - and many more things if you mix the different techniques.

Techniques

• Adjusting brightness and contrast
• Adjusting colour balance
• Adjusting colours via curves
• Layer duplicating and layer modes
• File saving and image uploading

Brightness and contrast

Adjusting the brightness and contrast of your image can often be a very useful technique. If you increase contrast very much I'd recommend you to increase brightness as well to prevent the image from getting "burned".

Step 1

For this lesson I have selected the following photo:

Click to view content: 

Step 2

Just open the Brightness and Contrast function, which is found under the Colours drop menu. Then adjust brightness and contrast as you want:

Click to view content: 

And now you're done! Your result should be somewhat like this:

Click to view content: 

Colour balance

Via the Color Balance function of GIMP you can add a certain colour to the image. This may often give your image the final touch; blue usually makes your image a little more "dreamlike", while adding magenta can simply give the image a nice look.

I'll use the same example image as above.

Step 1

I'll activate the Color Balance function and set the values as follows (notice the dialog under the drop menu) - usually when you are changing the colour balance you should keep the new colour values between -15 and 15 (this varies very much - sometimes you can adjust some colour to even something around 70):

Click to view content: 

Now the difference is quite subtle, but it is there.

Click to view content: 

Curves

Editing the brightness curves is sometimes preferable to adjusting contrast, while their effect is quite similar.

On the horizontal axle of the Curves window you see the brightness spectrum of your image. The vertical axle represents final brightness (I know, this is difficult to explain as well as understand). So, you can change black to white (without touching the other levels of brightness), for example, by selecting the Freehand curve type and drawing a vertical line up to the top of the window. At this point the curve should look a little like "V" but with the left cusp being all-vertical.

Because you did not get it (which I'm not surprised of) here's a demonstration:

Step 1

First off open the Curves window and set the curve somewhat like this:

Click to view content: 

You should play with this function a little so you'll get the idea of how it works. But anyways, here is the result:

Click to view content: 

Layer duplicating

Layer duplicating and layer mode changing is a very effective, useful and easy technique that can be used for various operations to increase the showiness of your image.

Step 1

Right-click on the image layer and select Duplicate Layer:

Click to view content: 

Step 2

Now select the new layer by left-clicking on it in the layers dialog. After this change the layer mode to Overlay by clicking on the layer mode drop menu.

Click to view content: 

Step 3

Under the layer mode you can see the opacity of the layer - now set it to 50 %:

Click to view content: 

Here's the result:

Click to view content: 

I suggest playing a little with those layer modes; they're very interesting creatures and can give you results which you could never reach without using and mixing them.

Saving the image

Now that you're ready you will want to save your image. You can save the file in many different formats of which these are the most important:

• .jpg/.jpeg: this is the most common file type, but I don't recommend using it as it typically decreases the quality of the image dramatically. That's because .jpg is a highly packed file format and thus requires less disk space - at the cost of quality
• .png: this is often the best choice for your finished works. PNG images are high-quality (even though you can adjust that when saving) and flat (they can't retain layers), but don't require a lot of space. Saving in PNG format doesn't maintain the layers, but the image will still look the same as in .psd or .xcf format
• .xcf: this is the own format of GIMP. You will want to use this or .psd (I always use the latter) to save your unfinished works as, for it will retain the layers and layer modes of your image. Remember, though, that therefore these files take more space
• .psd: this is the PhotoShop counterpart for .xcf: it can be used to save unfinished images (or images whose original, layered versions you want to save). PSD takes a little more disk space than XCF but it certainly has its' reasons to do so.
• .gif: this is the format for GIF animations. It's enough if you recognise it at this point, though, as I won't teach GIF animations to you during this course - it's more of an intermediate/advanced skill (damn, I can hardly create those myself - and all thanks for even that goes to Astaroth)

You can select the file format in this window when you are about to save your image:

Click to view content: 

However, you can do it faster by typing the extension (.png for example) here:

Click to view content: 

It is often useful to save your image both as .psd or .xcf and .png. You'll then have two files - one with the layers and one that has been flattened (the layers have been merged into one layer - this doesn't affect the look of the image though) and which you can upload.

If you want to share your work on web you'll have to upload your image to an image hosting site. Those include for example

• ImageShack (as I mentioned before I highly recommend this one - you have to register, though, but it's free)
• TinyPic
• Photobucket

To upload your image you first have to save it in the PNG format. To post images on TWC you must copy the direct link to the image you uploaded and put it inside IMG tags:

[IMG]link[/IMG]

And that's it - we're done with Lesson 1! You have now learned a very basic but important selection of colour techniques which you can use to improve photos and other images. Remember to keep on practising!

Homework

Edit two images by using the techniques I have taught on this lesson. Here are some nice photos you could use:

Click to view content: 

You can also pick your own images, but please provide me with the original image as well. Post the results in this thread by Tuesday the 8th of May.

Tips

• Try to keep the result natural-looking - like the original image, but with more showiness
• Mix the techniques I have taught above (but not too much - only a bit of each)
• Pick images that are large enough (at least 600 x 600)
• To quickly open an image in GIMP, right-click the image, click "Copy" and then paste (Ctrl + V) in GIMP
• Edit your images temperately - try to retain the naturality as said above. Don't apply too many techniques on the same image. Also you should avoid very high contrast or colour saturation

Optional exercise: do testing with layer options (layer modes, duplicating, curves and colour balance for example) by yourself - this will help you to get the idea of how all that works.

Optional exercise: read at least the first parts of my GIMP Basics Tutorial - it contains a lot of useful information that I won't be going through on this course.

As the homework for this lesson is very easy and quick to finish I highly recommend doing the optional "exercises" as well!

Lesson passed

• NekoGenijalan
• Legio
• Kameraden
• Shankbot12
• Gen. Chris
• King William the Conqueror
• Hader
• Soarin'
• ulti
• Maximinus Thrax
• Queen Chrysalis
• ForteS
• ✧Rarity✧
• lolIsuck
• megalitho
• Lü Bu
• Diamat
• Squid
• edse
• Påsan
• The Norseman
• Willowran
• Beorn
• SonofPeverel
• MasterBigAb
• Bolkonsky
• NobleNick

[NekoGenijalan]

I had some free time so I decided to do it right now. Are they any good?

Spoiler Alert, click show to read: 

Spoiler Alert, click show to read: 

EDIT:

Spoiler Alert, click show to read: 

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[Goofy]

I had some free time so I decided to do it right now. Are they any good?

It's nice to see you're eager to start.

Oh well, I didn't remember to mention that try to keep the outcome quite natural-looking.

So, the upper one has way too much green. Usually when you're playing with the Colour Balance function you should keep the new values between -15 and 15. However, the second one is actually pretty nice (yet not natural), although you may want to reduce the amount of black (or decrease the duplicated layer's opacity value - if there is one, I can't actually tell by that picture). You can also use the Color to Alpha function (Colors > Color to Alpha) to make black transparent on the new layer.

It would be good if you wanted to edit the pictures in a little more moderate way.

Remember - on this lesson you don't have to edit the images very much, just a little retouching on colours and contrast.

I'll be editing the lesson on some parts - that will mainly include minor changes and additional notes.

[Chlοë]

Use all the techniques on the two images or one technique on each?

Spoiler Alert, click show to read: 

ORIGINAL:


EDITED:




ORIGINAL:


EDITED:

As you can see I tried to make the bamboo look like it was taken with a camera from the 1960s.

[Goofy]

Use all the techniques on the two images or one technique on each?

Oh, that was taken into account in the original homework description - then I edited it the way it now appears (so the description doesn't actually mention that). But I just added this tip (I don't know if you posted before I added it):

Mix the techniques I have taught above

So, do anything you want - but make sure you use at least two techniques (all in all).

You can use all the four techniques in the same image if you choose, but the result may not be very great-looking.

EDIT: Great work Legio! Passed!

As you can see I tried to make the bamboo look like it was taken with a camera from the 1960s.

Yeah, it looks actually quite nice - the only flaw is the leaves on the left and in the middle: they're all-white, but that is due to the original image, so, great work as I said.

PS. Could you please put the images in spoilers?

EDIT2: NekoGenijalan: nice work - passed!

[Kameraden]

Reddish sundown thing, it might have made the sky a bit too purple.

Spoiler Alert, click show to read: 

Spoiler Alert, click show to read: 

[Shankbot de Bodemloze]

I can post

Pic 1

The orginal:

Spoiler Alert, click show to read: 

My version:

Spoiler Alert, click show to read: 

I think I might have gone OTT with the colour correction on blue And the duplicate layer is set to 25%

Pic 2

The original:

Spoiler Alert, click show to read: 

My version:

Spoiler Alert, click show to read: 

I think maybe it's a bit over-contrasted, but I wanted to try and get across a 'dark' sort of atmosphere The the duplicate layer is set to 50% on this one

NekoGenijalan I really liked your original waterfall one T's a shame teach didn't allow it

*quickly looks up at the profs face, I didn't mean it sir, honest *

[Gen. Chris]

First Image

Spoiler Alert, click show to read: 

Unaltered


Altered


Second Altered, per recommendation from Goofy

Second Image

Spoiler Alert, click show to read: 

Unaltered



Altered

Personally I really like how my sky turned out in the second image

[Shankbot de Bodemloze]

Indeed, it's not as purple Although I do like the 'ground' on Kameraden's

[King William the Conqueror]

Here is my work. Hope it works.

Original

New

Original

New

[Shankbot de Bodemloze]

I like how on the second one you've gone lighter instead of darker Maybe be a bit too bright?

I'm a big fan of high-contrast so you first I think is although the bush on the right-hand side is maybe a bit dark, but I'm one to talk I've done the same for my bamboo one

[Goofy]

Reddish sundown thing, it might have made the sky a bit too purple.

Well, maybe - that is good enough though. I'm still waiting for the other image.

On the other hand note it is easier to make a "reddish sundown thing" by using a new layer (mode set to Overlay) and a transparent-to-red gradient. We'll use gradients on Lesson 3, but if someone got interested and can do that with these short instructions, feel free to try.

I think I might have gone OTT with the colour correction on blue And the duplicate layer is set to 25%

I think you've added too much cyan and yellow - look at the pond above the waterfall for example. You can see the image is "burnt" - with this I mean that it is too bright in that part.
Try to do the same with more moderate changes.

The fault can be mine, though - the homework description for this lesson is a bit confusing. You shouldn't apply too many techniques to one image.

I think maybe it's a bit over-contrasted, but I wanted to try and get across a 'dark' sort of atmosphere The the duplicate layer is set to 50% on this one

Reducing brightness or adjusting the curves without the contrast increasing too much may be a good idea. A gradient would work well also, but I don't (as said above) expect you to be able to use them at this point.

NekoGenijalan I really liked your original waterfall one T's a shame teach didn't allow it

I liked it as well, but I'd like to see even better work by him.

*quickly looks up at the profs face, I didn't mean it sir, honest *

That's it - you're off to the detention!

Personally I really like how my sky turned out in the second image

It has a pretty decent effect indeed. Too bad the image is a bit of low quality; the shrub on the left looks weird because of the high contrast. Good work on that image though!

As it comes to your first image, I think you have the same issue as Shankbot12 - you have either added too much colour (in your case mainly green/yellow) or applied too many techniques on the same image.

Here is my work. Hope it works.

On the first image - very good, but the contrast is way too high. And as Shankbot12 said, the second image may be a bit too bright.

I think you (Shankbot12, Gen. Chris and King William the Conqueror) should make a little more temperately edited versions - try to keep the look quite natural!

Don't give up yet, and don't take my critic personally - I'll do my best to make you learn! Legio's results are pretty good - look at them if you need more examples!

[King William the Conqueror]

Okay

So you need a new one of both or of just the second one?

Original

New

[Gen. Chris]

Actually that was the effect I wanted for my first one. And I only used one technique.


EDIT

How's this instead?

Spoiler Alert, click show to read: 

[Shankbot de Bodemloze]

*Shankbot12 storms off out of the class whilst mumbling back to the drawing board - and I've got the bloody detetention! Thanks a lot teach you little -

"Ah Shankbot12, what were you about to say?" The teach booms, leaning over from the desk.

"Nothin' sir, I swear down," comes the mumbles reply, as Shankbot12 stuffs his hands in his pockets and carries on walking out.*

I'm on it prof I was just about to start an AAR update so will tomorrow be okay? If not just let me know... I don't want another detention

EDIT: *he runs into Gen in the hall. "Hey Gen wasup!" Shankbot12 says, trying his best to impersonate a 'bad-man'

"Nothing just finished my second attempt is all." Gen says, showing of his new work to Shankbot12, or Shankzzz as he wants to be called

"Nice!" says Shankbot12 with a clap of approval before storming even more angrier than before, at least someone else has finished.

"Cheers, bye, bye, bye," Gen says running off back into the class.*

[Goofy]

You don't exactly have to do any improvements - I just want to make you do your best. Also, to prevent this thread turning into a general graphics discussion I'll just point out the things you might want to change, and you can then decide if you do that or not.

You have all passed the lesson (except Kameraden).

Okay

So you need a new one of both or of just the second one?

I would like to see a less dark version of the first image, if you don't mind.

Actually that was the effect I wanted for my first one. And I only used one technique.

Ah, I see. You can't tell at a glance which techniques have been used. And if that was the effect you wanted, then I'm all fine with it.

How's this instead?

I prefer the first one - this is too dark.

I'm on it prof I was just about to start an AAR update so will tomorrow be okay?

You can do that if you want.

When you decide to improve your results, please start it from beginning - open the original image and start working on it again.

EDIT: Good work with the new one, William!

[Gen. Chris]

...So...Recess time? .

[King William the Conqueror]

I would like to see a less dark version of the first image, if you want.

Good work with the new one, William!

Thanks.
Here is the first one redone.

Original

Old

New

sorry it is hard to tell the difference

[Shankbot de Bodemloze]

You don't exactly have to do any improvements - I just want to make you do your best. Also, to prevent this thread turning into a general graphics discussion I'll just point out the things you might want to change, and you can then decide if you do that or not.

You have all passed the lesson (except Kameraden).

You can do that if you want.

When you decide to improve your results, please start it from beginning - open the original image and start working on it again.

Sir, I'll stop the talking

Here we go (again): - using the orgianl images and doing the dual save thing *Shankbot smiles gleefully at being a good boy*

Photo 1

The original;

Spoiler Alert, click show to read: 

My new version:

Spoiler Alert, click show to read: 

No layers this time, and a gentler touch with the colour correction

Photo 2

The original:

Spoiler Alert, click show to read: 

My new version:

Spoiler Alert, click show to read: 

Again, overall just a gentler touch Although I seem to be having problems with this one, the left-hand side branch is too bright and the right too dark

Hope these are better sir If there not just let me know and I'll give it another shot

[Goofy]

@Gen. Chris: Yes. The next lesson will be posted on Tuesday or Wednesday.

@King William the Conqueror: I think you should reopen the original image and then do what you did, but with a softer touch.

@Shankbot12: Great work this time! Even though your touch may just be a little too gentle. And I think the image is all-fine - the exposure of the photo is the reason to the light on the left. You can't change that. And the right side is very good.