Ho-Hum to Wow! in Gimp

Ho-Hum to Wow! in Gimp



Some time ago I wrote a blog post called “Turn Ho-Hum Color into WOW! with Photoshop” which involved using the LAB color space to adjust an image. In the interests of those of you who use Gimp, this blog post is a revisit on the topic of dragging color out of lackluster images this time using Gimp.

One of the hidden secrets of Gimp is that it supports the LAB color space so you can get access to the L, a and b channels in an image. This adjustment therefore produces similar results to those you can achieve with my earlier post using Photoshop it’s just that the process in Gimp is a little different.

Start out with an image that could use a color boost. This image of a statue over a door in Paris is very monochromatic so it’s a great contender for this process.


Start by making sure your Layers panel is visible – if not, choose Window > Dockable Dialogs > Layers (or Control + L) to display it. Right click the Background layer and choose Duplicate Layer. Select this new top layer.


To convert the image to LAB color, choose Colors > Components > Decompose. From the color model dropdown list, select LAB. You will want to decompose to layers so select Decompose To Layers and click Ok.


You’ll have a new image on the screen with three layers. Right now you’ll be looking at the L channel and below it in the Layers palette are the A and B channels.


Disable visibility on the L layer and click the A layer to select it. You should have a dark murky almost negative looking image on this layer. Choose Colors > Curves and adjust the curves by dragging the top right and bottom left points on the curve one, two or three boxes inwards on the grid. You can read off the values so pairs of values like (30,0) and (225,255) or (64,0) and (191,255) are good.

You need to make sure the line goes through the middle of the grid, or you will get an unwanted color cast in the final image. This A channel controls the Magenta and Green in the image and you’re boosting it now to very high levels. Click Ok.


Repeat this by disabling the visibility on the A channel and do the same on the B channel. This is the Yellow/Blue channel. When you’re done, turn back on the visibility of all three channels. You should see no difference in the image at this stage.


If desired, you can adjust the contrast in the L channel using curves – this will give you some additional boost in contrast in the final image. The L channel is the luminosity channel and it has no color in it at all so you can create a different shape curve here and there is no requirement for the line to go through the middle of the grid.


When you’re done, choose Colors > Components > Recompose. The layers will be recomposed back into the original image.


To see it, you will need to close the LAB version and return to your original image. Because you’re working on a duplicate layer, you can now blend the top layer by selecting a different blend mode such as Overlay for the top layer and then adjust down the Opacity to suit.


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Helen Bradley is a Lifestyle journalist who divides her time between the real and digital worlds, picking the best from both. She writes and produces video instruction for Photoshop and digital photography for magazines and online providers world wide. She has also written four books on photo crafts and blogs at Projectwoman.com.

Some Older Comments

  • Steve November 8, 2011 10:00 am

    Thanks for adding GIMP tutorials.

    There is an easier way to do this, but you have to download a free filter called SmartCurve.

    Just duplicate the layer, then open SmartCurve (when installed, it falls under Filters -> easy.Filter). Chose LAB as the color space and do the same adjustments as shown in the tutorial. While the tutorial shows you a viable approach, using the SmarCurve tool provides a much better and more intuitive interface to accomplish the same thing (you can also save the curves with that tool too).

  • Frank November 7, 2011 12:23 pm

    Thanks for a tutorial about an open-source graphics application. Too often these excellent (IMHO) applications are not given proper consideration. Is PhotoShop worth the $600-800 price tag for a photographer with limited funds? I would rather spend such funds on an upgraded lens.

    I believe that Gimp does support printer profiles. Check on-line - google the question.

  • charlie November 5, 2011 11:39 am

    Does Gimp support printer profiles? Seems like this would be a major sticking point...

  • David November 5, 2011 10:07 am

    Thank you so much for the GIMP tutorial! It's what I use and I have always wondered about fixing colors.

  • Gimped! Gimp Tutorials November 4, 2011 12:51 am

    What a unique way to adjust exposure in an image, I'll definitely be keeping this in mind, especially with the layer masking implications that this could produce.

    I will often create a grayscale copy of a layer for my layer mask, and adjust the exposure to have gimp only modify high points (or low points if I invert the image.) This process wildly differs from what you did here, although LAB mode may support some unique layer masks that I previously didn't have access to.

    Thanks so much for sharing this.

  • phototekie November 3, 2011 08:38 am

    Thanks for the tutorial, Helen.

    While I know the intent of the tutorial is to teach how to do this in GIMP. However, comparing it to LR3, would the comparative steps in LR3 be to adjust Vibrance and Blacks? Just curious...

  • Jeet November 3, 2011 05:24 am

    Sorry, can't seem to make the link work. The image is at:

    (You'll have to copy and paste in browser's address bar)

  • Jeet November 3, 2011 05:19 am

    I've tried different settings as shown in image below:

    The amount of correction for a and b layers in each image is mentioned. For the last one, I used auto levelling on each L, a, b layer.

    Helen's method improves the original image a lot. But I think that colour enhance followed by levels adjustment gives the best effect of the lot (3rd from left, top row). This may or may not be true for all images.

    Comments and advice are welcome.

  • Jeet November 3, 2011 01:28 am

    P.S. Is there any effect on grain at 100% crop?

  • Jeet November 3, 2011 01:27 am

    and Mandeno, terrific effect, almost like coming alive

  • Jeet November 3, 2011 01:25 am

    We aren't paupers tj, I rather think open-source users are open-hearted as well.
    If only I can get the time tonight to try this out, cos till now all I do is 1. Colours>Levels and 2. Auto>Colour Enhance

  • Rick November 3, 2011 01:20 am

    There are few high quality tutorials for GIMP out there, but this is definitely one of them. This software often gets a bad rap because it isn't Photoshop, but don't be fooled: You can do a lot with it. The problem is people don't take the time to learn how to use it well, so it often gets associated with subpar photography.

  • tjmurph9 November 3, 2011 12:33 am

    Magic Helen! And very clearly explained too! I also tried the first of the 4 easy Photoshop tips in GIMP and got a terrific result as well. Good to see we GIMP paupers aren't being forgotten amongst all the resources for the Photoshop sheep.

  • Mandeno Moments November 2, 2011 11:22 pm

    Thanks for remembering the oft-forgotten Gimp. The clarity of your instructions is superb.

    I experimented with one of my photos and you can see the result at http://wp.me/pkqf4-qw

  • Tom_Vienna November 2, 2011 10:53 pm

    Thank you for this tutorial Helen. I use Gimp a lot, but never discomposed and recomposed a picture the way you showed. I can´t wait to give it a try this evening :-)

  • Mayooresan November 2, 2011 10:43 pm

    Wow that is awesome. This tutorial do makes my pics taken in mobile into something splendid :) Thanks alot.

  • Jeet November 2, 2011 09:18 pm

    Thank for a very useful article, Helen. I am just starting out in GIMP and can use all the help I can get.

    @Bekah: I'm like that too, and I think I'll be sticking to the GIMP for some time.

    @Jason: Yes, it might be easier the way you mention, but remember that the GIMP is open-source software, and the steps mentioned above by Helen can be compiled as a script/plugin 'by anyone' to quicken things up. Photoshop, Lightroom and I believe Color Efex and Topaz, all cost a bundle of money most GIMP users have no intention of throwing into the wind.

  • SpeedyGonzales November 2, 2011 05:41 pm

    Thank you for the GIMP tutorial! Please keep those coming. GIMP is an excellent, powerful, but sadly underrated and overlooked piece of software.

  • Jason St. Petersburg Photographer November 2, 2011 03:11 pm

    That seems like a very complex process. In my digital photo editing career I thankfully early on found Color Efex Pro and created a work flow of using 2 or 3 filters that can take photos to wow.

    In this example I used one Topaz adjust filter as well:


  • Justin Ennis November 2, 2011 12:56 pm

    Oh thank you thank you thank you for the Gimp tutorials! This is exactly what I needed!

  • Hefjar November 2, 2011 05:55 am

    This looks like something you could just do with curves...

  • Bekah November 2, 2011 05:16 am

    I really appreciate gimp tutorials! At this point, I'm just a photo enthusiast and I don't really have the money to buy Photoshop or Lightroom just yet.

  • Jerry November 2, 2011 01:12 am

    Coincidentally, this is a method I have been experimenting with recently. It is very useful:
    Duck Stretching a Wing