Selective greyscale in The GIMP

I decided to make a selective greyscale image in The GIMP, and as lots of friends say to me that they would like to use The GIMP more but don’t know how, I thought I would write a bit of a walkthru for how I did it.

orange flower

Starting with your colour image, use the lasso tool to select a large chunk of the area you want coloured (this is optional but usually makes things faster)

snapshot1

The next step is to get a coarse selection of the area we want coloured. You can use the “select by color” tool if the colour is pretty distinctive in your image, or use the “select contiguous regions” tool as I did. Holding shift will force the tool to add to the selection (otherwise it might try to move it if you click on an already selected area). Keep shift-clicking until you have most of the area you want selected.

snapshot2

Next use a quickmask to start fine-tuning the selection. In the bottom left of the image window, click the little red box to turn on the quickmask. The red area is the area outside of the selection, so we want to make everything around the flower red.

snapshot3

Select a large paintbrush and paint in the areas you want to be in your selection. Painting white will add to the selection, painting black will remove from the selection. If you make a mistake you can use undo, or paint with black to correct (you can swap the foreground and background colours by clicking the arrow by the colour selector)

snapshot4

Move to a smaller brush to fine tune the selection.

snapshot5

When your selection is good enough, turn off the quickmask again by clicking the little red square in the bottom left. At some point we need to make a copy of the layer, so we can do that now by right clicking the layer in the layers dialog box, and selecting “Dupicate Layer”. When you have 2 layers make sure you select the top one before continuing (most actions in the gimp only affect the currently selected layer. Don’t worry, your selection in the image does not depend on a layer, so will not be lost. Of course, you could have done this before starting the editing too).

newLayer

Next we will feather the selection a little, this makes the edges of the selection slightly transparent, which makes the effect look a little better. Either right click on the image to get a menu or use the menu on the top of the image window: Select->Feather.

Next we want to make a layer mask on our top layer. Right click on the layer in the layer menu and select “Add Layer Mask”, then select “Selection” when asked what to initialise the mask to. A layer mask restricts what is visible of the layer, so we are going to make only our selection visible.

snapshot6

By clicking the “eye” icon on the bottom layer, you can hide the layer from showing, which will allow you to see your new masked layer of the flower (don’t forget to turn it back on though).

snapshot7

Next we need to make the background greyscale. First make sure you don’t still have a selection by pressing CTRL+SHIFT+A or Select->None from the menu. Next select your background layer in the Layers dialog.

selectLayer

There are several ways to make an image greyscale, the simplest is to desaturate the layer (this will make the current layer greyscale). From the right click menu, or menu bar at the top of the image, select Layer->Colours->Desaturate

snapshot8

And voila, your background is grey, your foreground is in colour.

snapshot9

There are of course other ways to achieve the same effect, I have only shown one.

Hopefully you found this useful and will consider The GIMP for your photo editing. Let me know if there are any other common tasks that you would like to know how to do in The GIMP and I will probably write up about them.

About Anton Piatek

Professional bit herder, amateur photographer. Linux and tech geek
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10 Responses to Selective greyscale in The GIMP

  1. Thanks for these easy to follow instructions! Well written and actually worked. Only one small thing I’d change: Duplicate and make the grey-scale image first before doing anything, then start the right-clicking. Painting the quickmask with white certainly speeds up the process – but I’d love a WACOM tablet to improve the quality of vertical and horizontal lines!
    Using your technique I was able to produce this pink flower on a grey background in just under two hours. Not bad for a first time!

  2. Anton says:

    Glad you found it useful!
    I will try to think of some more gimp tutorials soon, so check back to see what I come up with.
    Duplicating the image first might work better as you say. There are other ways, but I would need to play with them to remember exactly how to do them.

  3. Leo says:

    Thank you 😀
    it is as just as stephentrepreneur saied:easy to follow instructions! 😀
    and thanks that it is Gimp and not Photoshop….

  4. tiny tim says:

    wow, got this on stumble. Have seen a million tuts on how to do it on ps but none for the gimp. Brilliant! please do more tuts and you might get a bookmark 😉

  5. IGD says:

    Great tutorial.. But there is an easier way to do this. Just select the part of the flower you want in color. Copy paste in another layer. Desaturate the entire picture (layer 1) and voila!

  6. Samantha says:

    Even easier way…

    Duplicate the image, desaturate the copied layer, and erase the portions of it that you want to be colorized…

  7. Anton says:

    As I said – there are loads of ways of doing it.

    Use whichever seems easiest to you!

  8. kristi says:

    does any one know how to turn grayscale OFF i must of accidentally turned it on and dont want it on grayscale

  9. Anton Piatek says:

    @kristi you have probably set the colour-depth to greyscale, and this causes gimp to only allow your image to have new colours that fit (i.e. only greys)
    Try Image->Mode->RGB

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