Will Knott

Hello again.

This post is going to be very image intensive, and I’m used thumbnails to help the bandwidth impaired.
Click on the image to see a larger version.

A quick word on Selective Colourisation, someone asked “what is it”…
Well, this is a colour image.

and this is the same image using selective colourisation on the yellow parts.

Effective isn’t it. The technique works best on a strong colour, unfortunately pink has many shades. Something which complicates things later on. And when yo do this technique on your own images, clean them up first. Red eye looks silly in black and white. However you could try selective colourisation and have a black and white photo, with red glowing eyes. Very zombie.

Anyway, in part one you downloaded your tools, and I gave you an image to play with.

So lets start.

Open the photo and you’ll probably have this view. The picture itself and the toolbar. However, in order to do make the changes, you’ll need to see the layers. To bring up the “Layers Dialog window” from the menu bar of the photograph, choose “Dialog” and then “Layers”.

And you then have the layers window.

What we are going to do first is create a new layer (a copy of the photograph) and turn that copy in to a monochrome version.

So go to the menu bar of the photograph again, and this time choose “Layers” and “Duplicate Layer”.

This… does nothing to the photo. But if you look at the layers window, you can see that there is now a second entry.

Make sure that the upper-most layer is selected, because we are finally going to make that colourful photograph a lot less colourful.

To make the image black and white, go to the menu bar of the image (who by now is an old friend) and choose “Colors” and “Desaturate”.

This causes a new window to open asking you “How do you want to make this image black-and-white”.
Actually its asking “How do you want to make this layer…”, but you’ve probably going “I don’t know which one of Lightness, Luminosity or Average to pick”.

Well don’t worry about it. Remember how I said that selective colourisation works best with a strong colour. You will want the maximum contrast between your selected (eventual) colour and its surrounding monochrome. So at the moment you can’t know. If you want to be really sure, you can always take the same image make multiple layers… and try out the technique on them all. Then you can pick the best looking one. Or make use of “undo”.

Anyway, pick one.

You now have a black and white image. But if you look at the layers window you can see that the colour photo is still available. (You can click on the green arrows at the bottom of the layers window to change the view between the black and white image and the colour one).

So now its time to put some colour back. You don’t use some colour selecting tool, but a mask.

Go back to the picture’s menu bar, and choose “Layers” then “Mask” and “Add Layer Mask”.

This causes a window to pop-up. The default here is “White (Full Opacity)”, choose that one and click “OK”.

The way we get the colour back is to “cut” through the monochrome image. If you look in the layer window you can see that there is not a white rectangle next to the monochrome image. This is the layer. White here means that you can only see the selected layer. Black here means that the layer is transparent, which lets the image in the layer below show through. To do this we’ll use the paintbrust tool from the tool bar.

The paintbrush is the 4th from the left and the 4th one down. Pick this tool and you should see the selected (and alternate) colour for the brush. The topmost one should be black, and the one below it should be white. You can see the selected brush in the image above its called “circle 11″.

You can try out the process. Put you mouse over the image and holding down the primary button, scribble on the image.

See the colour show through?
You can easily get rid of this scribble by choosing “Edit” and “Undo” from (you guessed it) the menu bar of the image.

While the above brush is fine, you should really chose a fuzzy brush. Its more forgiving if you go over the edge of the item you want to return to colour. Click on the “image” of the brush and you’ll see a selection of brushes. Pick a fuzzy brush (you can switch over and over)

and go back to the photograph.
Before you start re-colouring the image, you had better zoom in (“View”, “Zoom” and either “Zoom In” or select a ratio) so that you can more accurately colour the image.

Now you can start to colour in your photo. Use small strokes, that way you can use “undo” as needed.

Personally I prefer to go along the edge of the part I’m colouring in. Filling in is the easy part.

At this point it might be worth looking at the mask itself. Choose “Layers”, “Mask” and “Show Layer Mask”.

And you can see the parts I’ve changed.

You can also see a little “scratch” next to the sleeve. That is a mistake for which I can’t use undo. I can however use the paintbrush to make that black mark white again.

Back on the toolbox, you can see a little two headed arrow where the chosen colours are. Clicking on this will switch the colours.

Now with my brush “painting” in white, I can erase the mistake.

Switching the colours back to black, I can cheat.
Since I “painted” the edge of parts I want to re-colour, I can use the “fill” tool (in the picture above it’s the left-most column, 4th one down with an icon of paint being poured from a tin) to, well, fill in a chunk of the image…

… and switch back to the brush to tidy up the image.

When you are doing the selective re-colourisation, I’d advise you show the mask so you can see if you missed a bit.

You can now turn hide the mask (“Layers”, “Mask” and select “Show Layer Mask” to deselect it) and see the image.

Using the green arrows in the layers window to see the full colour and selective colourised image to see if there is another part you wish to colour in.

Now it’s time to save your image. Go to the menu bar and choose “File” and “Save as”.
Why “save as”? Firstly, if you are using a borrowed machine, you need to make sure you are not overwriting the original image, and that the location you are saving on is going to be on your own removable media. The other reason? Well, GIMP uses the file name extension (the 3 letters after the main file name) to decide how its going to save the image. If you save with a “.xcf” then you are saving n GIMP’s own native format. And it retains all your layer information if (like me) you will need to return to the file to edit it. If you don’t want to return to editing, then the file name extension of the image file sill still be set to the file type you opened (in this case a JPEG or .jpg file).

When you save after editing you are going to get a few warning boxes.

This one reminds you that you are going to loose your layer information. Since that’s the point choose “confirm”.

This one tell you that since a jpeg can’t handle the transparency its going to turn your multi-layer image in to a single layer one. Again that’s the point; choose “export”.

And finally (you will get this one)

The scroll bar on the top wants to know about compression. Since these images are going to be for printing, choose 100%. However if you are just trying out the technique, (and the 100% reslts in a large file size) you can leave the quality levels at a lower setting. Once you are happy with the quality setting click on the “Save” button.

We now have a selective coloured image.

If you look at the pointing hand, I didn’t colour in the cuff. This if you remember is the difficult part.
I could use the same careful drawing technique that I used before (or just leave it as it looks OK) but I won’t.

I’m going to leave it to you. This is the reason for the half post. I want you to tell me the techniques you used to colour in this part. Leave a comment below or e-mail me I’ll post the replies next week.

Take care,
and do your homework,
Will Knott

Tags: Breast Cancer, cancer, gimp, photo editing, pink for October, pinkforoctober, Selective Colourisation, software

This entry was posted on Friday, August 15th, 2008 at 12:03 am and is filed under Breast Cancer, cancer, photo editing, pink for October, pinkforoctober, software. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.