GIMP adapting saturation

Hi,

I'm just wondering if it's possible to convert this tutorial with GIMP 2.6 ? I can't find any adjustment layer in GIMP...

http://www.clippingimages.com/blog/adaptive-saturation/


Cheers,
Ced.

Quote:

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Originally Posted by cedricb

I can't find any adjustment layer in GIMP...

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Ced

Welcome on board the C in C forums site. Hope you'll stick around, enjoy yourself and ask lots of questions.

I asked the exact same question about 15 months ago when I joined this site. (And just to prove it, click here for that thread and the very helpful reply that I got). You are correct. The GIMP doesn't have adjustment layers in the same way as the Adobe family of products. We GIMP users just have to get smarter with Layers and Masks.

Although there's a lot more information out there about Photoshop etc, there's still a lot about the GIMP. My own recommendation would be to sign up www.meetthegimp.com. Click on the Table of Contents tab in the right hand pane and you will see details of over 140 video tutorials that take you through things step-by-step.

Thanks for the warm welcome! I did see your original thread but it's difficult to replicate PS/GIMP layers...

As there currently no adjustment layer available.......

I like duplicating the layer and selecting Overlay Mode then reducing opacity until I get the best saturation increase........
An alternative is to use the Lab Mixer in G'MIC adjusting a and b.........then there are color scripts such as Wow to adjust color and saturation....

Will

Another resource on flickr. They're a friendly bunch but have a search first. :)

I think what you are trying to do is use a mask to control the amount of saturation, the mask that is used is an adaptive mask based on the image.

Reading through the tutorial link you posted I think the way to convert it for gimp is to forget the adjustment layers, in gimp an adjustment layer is a copy of the image set to a blending mode so in this case:

copy the image by duplicating the layer

Create a new white layer above the new layer and set its blend mode to difference, this will be your difference layer

Add a white layer mask to the difference layer

Duplicate the Image layer again and desaturate it, then select all Ctrl A and copy Ctrl C, click on the layer mask in the difference layer and paste Ctrl V will now have to press the anchor Icon to merge this down into the layer mask.

Now you have a difference layer with a layer mask right click and apply the layer mask, you will have to desaturate this layer now you can set it back to normal as well.

To aply the adaptive saturation mask just dulicate your image and add a layer mask copy the mask your created and anchor it down into the layer mask. set the blend mode to which ever you prefer or leave it as normal and apply your edit such as curve, unsharp mask for local contrast etc etc.


Well thats at least how I think it interprets into gimp :)

I have been playing around and the apply image command in photoshop seems to blend to layers together the closet im gimp would be a stack of layers.So after playing around I have adapted what I wrote earlier:

Copy image layer twice

Create New white layer above set mode to difference

Set the image layer below the white layer to multiply

You should have a strange looking purpley green image

Merge down the copy image set to multiple on to the other copy image layer

Now merge down the white difference layer onto the layer below

You now have one layer desaturate this layer and use it as your layer mask for example copy your image as a new layer add layer mask, select the new saturation layer mask select all and copy, paste into layer mask. And then adjust your images saturation with either hues saturation, channel mixer, curves etc etc.

Turns out its even easier thaan everything I wrote!!!! :eek: haha

Found the bottom bit on the meet the gimp forum so wether this links back to there I dont know but here is what was wrote on there

(sorry I forgot the link this is someone elses work but it works great for all those who would like to know how its done)



Adapting saturation

•Duplicate your layer
•Change the layermode of the duplicate layer to "Difference"
•Desaturate the duplicate layer
•"Layer->New from Visible"
•"Edit->Cut" (the new layer will be deleted)
•Delete the duplicate layer (we are now back to the original layer, but the paste buffer contains the mask image we need)
•Duplicate the original layer
•Add a layermask to the duplicate layer
•"Edit->Paste"
•"Layer->Anchor" (the paste buffer is now pasted into the layermask)
•"Color->Levels" and click on the "Auto" button

At this point, if your goal is to modify the saturation of the most colorful regions then you can skip ahead to the next paragraph. If your goal is modify the saturation of the more desaturated regions then you should perform a "Colors->Invert".

Click on the thumbnail preview of the duplicate layer to activate the layer. Now you can use the Saturation slider in the "Colors->Hue-Saturation" dialog to change the saturation of either the highlights or shadows (depending upon whether you inverted the layermask as described in the previous paragraph).