Quick Masking with GIMP Tutorial

Here I am with another tutorial for you!
Who hasn't seen a THUM in your poselist for a couples pose where one of the sims is in Black and White and the other in color and wanted to do the same? This tutorial will show you how to get the same effect for your own pics using the Quick Mask feature in GIMP.

First of all- Open your image in GIMP.

Next, Select your magic wand and select an area on the image. Preferably somewhere on your sim who is in the foreground.

Depending on your threshold you'll get something like the above.
Next- click on the little dotted box in the lower left hand corner of your image. This is the Quick Mask button.

The Quick Mask button is now a red box and your image should now look something like this. The areas overlaid with red are areas NOT selected. The areas where the original colors come through is where the image IS selected.

Next, select your paintbrush (or pencil or airbrush) and using pure white (#FFFFFF) paint over the area you want selected. You'll see that Layla's face is now showing through the red. There is no point in being too exact at this stage.

Go ahead and paint white nearly everywhere you want selected.

Next, we'll deselect what we don't want selected.

This time, change your color to pure black (#000000) and paint the areas you don't want selected. You can see where I've already done this both on the background and on Ignacio's legs. Again- you don't have to be perfect at this stage.

Now you can see I have a rough idea of what is selected and what isn't. At this point go ahead and make your selection as detailed as you'd like by zooming in, using smaller brush sizes, and/or  feathered brushes.

Here is our completed mask.

Click on the Quick Mask button again and you'll now have 'marching ants' around where Layla, and only Layla, is selected. (See on her shirt front where the marching ants are on her buttons? You can switch back and forth between Quick Mask and regular views as much as you need to make sure you don't have anything selected you don't want, and vice versa.)

Now, go to your colors menu and select Desaturate from the drop down menu. (Or, use a B&W filter from the filters menu.)

The part of the image you have selected should now be grayscale.
Save/Export this image.

When you have saved/exported, click undo to undo the B&W. Then click on the Select Menu. From the dropdown menu select Invert. Once you've done this select Colors->Desaturate again.

Now, your foreground sim should be in color while the rest of the image is grayscaled. Again, Save/Export your image, be sure to use a different file name. And now you can make your THUMS for your poselist as usual with your nifty images.

Here are my two finished images-

Questions? Need Clarification? Feel free to ask!