On Friday 11 April 2008, norman wrote:

I am trying to gather information on how to convert from colour to black & white. In my searches I came across the following which is in photoshop:-

http://www.northlight-images.co.uk/tutorial_pages/elements_2/PSE2_BW.html

Could some kind person please explain to me how I do this in GIMP so that I can add it to my list of things to try.

Norman

Hello Norman,
http://www.gimpguru.org/Tutorials/ has a lot of thing to add to your list. But in the end it's up to you to try them out and find for each image the method that works best.

Have fun! Daniel

On Fri, Apr 11, 2008 at 1:24 PM, norman wrote:

I am trying to gather information on how to convert from colour to black & white. In my searches I came across the following which is in photoshop:-

You might also want to take a look at: http://meetthegimp.org/episode-034-full-control-monochrome-conversion-3/

On Saturday 12 April 2008, norman wrote:

I have looked but this does not answer my specific question, unfortunately. I cannot believe my question was so obscure that no one has been able to answer it yet. Perhaps it is too simple and I am missing the point somewhere.

Norman

Yes, maybe you should rephrase it, I'd thought that you wanted to know methods to have more control than with one of the straightforward methods: - Image->Mode->Grayscale (the whole image will be grayscale, you'd have to change back to RGB mode to edit with colours again) - Colors->Desaturate, which has three predefined modes since GIMP 2.4

If that's not what you want, maybe you should ask again in a different way ;-)

Daniel

On Saturday 12 April 2008, norman wrote:

Yes, maybe you should rephrase it, I'd thought that you wanted to know methods to have more control than with one of the straightforward methods: - Image->Mode->Grayscale (the whole image will be grayscale, you'd have to change back to RGB mode to edit with colours again) - Colors->Desaturate, which has three predefined modes since GIMP 2.4

If that's not what you want, maybe you should ask again in a different way ;-)

Right, I could explain but, as it is said, a picture is worth a thousand words. I was looking at the following and would like to be able to do what is described, using GIMP:-

http://www.northlight-images.co.uk/tutorial_pages/elements_2/PSE2_BW.html

There are 2 things I am puzzled about they are:- how do I create an H/S Adjustment Layer and why is the background copy in b&w whereas the layer labelled background is in colour as is Background copy 2.

Norman

There are no such things as adjustment layers in GIMP, but in one of the future versions, much more powerful tools will be available to allow non-destructive editing. You can do pretty much of what's done there though in different ways as mentioned on the page that Tim gave. As to why the BG copy 2 layer in your page is b&w, I best quote that page itself:

"the top layer (Background copy) shows where we did a simple 'remove colour' and have de-selected the 'eye' so as to hide this layer."

The coloured seem to be effectively desaturated with one of the adjustment layers.

On Sat, 2008-04-12 at 12:48 +0100, norman wrote:

< snip >

There are no such things as adjustment layers in GIMP, but in one of the future versions, much more powerful tools will be available to allow non-destructive editing. You can do pretty much of what's done there though in different ways as mentioned on the page that Tim gave. As to why the BG copy 2 layer in your page is b&w, I best quote that page itself:

"the top layer (Background copy) shows where we did a simple 'remove colour' and have de-selected the 'eye' so as to hide this layer."

The coloured seem to be effectively desaturated with one of the adjustment layers.

Thank you very much indeed. Now I can forget all about the approach I thought I would look at and concentrate on those ways I know best - the methods suggested and demonstrated by Ralph Steinort.

"Rolf" please! ;-)

I think this is basically the same thing that you can do with the channel mixer.

In the top adjustment layer they do a "crude" desaturation by simply removing it. You can do that in Gimp by adding a layer filled with black and setting the mode to "saturation".

I don't get what the lower layer does. I'll ask a friend an d report back. Perhaps there is something interesting in it.

Rolf

On Sat, 2008-04-12 at 16:22 +0200, Rolf Steinort wrote:>

< snip >

I don't get what the lower layer does. I'll ask a friend an d report back. Perhaps there is something interesting in it.

Nothing interesting.

I just talked to John Arnold from http://photowalkthrough.com/ (worth to look into even for Gimp users). He told me that this is an old method and has less control than the channel mixer.

The lower layer just rotates the colours. That leads to a different luminosity and so to different monochrome output.

Rolf

Last attempt...

...of course between the layers that GIMP has and the Channels, I'm sure that it is not impossible to emulate adjustment layers. You should note that each layer in the GIMP is fully functional. Some things you can do with them include applying a filter, like dodge, burn, multiply, or overlay, which works non-destructively on the entire layer. I'm guessing from your response, Norman, that none of us were answering correctly, that I didn't look at the Photoshop tutorial very well that you referenced in your original question.

Looking at the tutorial more closely, here is what I'd suggest resembles the tutorial in your first post, but it requires two less layers than the four given in the tutorial for Photoshop:

1. Load the photo in question 2. Duplicate the "Background" layer by clicking on the Duplicate (or copy layer) button in the Layers dialog
3. Click on the "Background Copy" layer in the Layers dialog 4. Adjust the Mode for this layer by clicking on the Mode drop-down box and selecting Hue (near the bottom)
5. Right-click on the image
6. Select Colors > Hue-Saturation... 7. In the Hue-Saturation dialog, move the Saturation slider down (in a negative direction) until you get the black and white levels you desire.

That's as close as I can get to the same thing. In my opinion the GIMP's is much more straight-forward - namely have filters on discrete layers, rather than Photoshop's having a filter stack.

Nathan

I attached a zip archive containing the three images I worked on using the technique described above. And a fourth that is only slightly desaturated.

I couldn't get these to you, so here are some links to them - they are GIMP 2.4 XCF files, so you'll see all of the layers and such when you load them in GIMP:

http://www.mediafire.com/?j0gdzitgg2y http://www.mediafire.com/?xgaipryzm31 http://www.mediafire.com/?pgywazmwgeo http://www.mediafire.com/?dgzi99gmjos

The original stock photograph used is attributed here: http://www.sxc.hu/photo/981014

Daniel Hornung said:

There are no such things as adjustment layers in GIMP...

No problem - I agree with you that using varied procedures to do things produces a better understanding of the tool as a whole. If education is your goal, then I think that already, you have learned a large number of options to convert an image from color to black and white. To get even deeper into image manipulation, you might try using the selection tools, including the quick mask (button in lower left-hand corner) to enable working on only a selection layer, as opposed to the whole image.

Something I also just realized about the Photoshop tutorial you referenced that might make more sense in GIMP is to use multiple layers as your "image history". You can use layers in one or two ways in the GIMP. Naturally they good for distinguishing between parts of an image. For example you might have one layer containing a field, and a second layer containing a small house, placed on top of the first layer. Also using layers, you could create copies of your image as you make changes, in effect creating your own rudimentary filter stack (like those found in Adobe/Macromedia products.)

At any rate. Keep asking questions. Keep experimenting. The GIMP is one of the most powerful image manipulation tools in the world. The only thing that might make it appear less is the lack of pre-programmed plugins, I suppose. But it incorporates all of the granular functionality of commercial tools easily, like Photoshop or Illustrator.

Nathan

On Mon, Apr 14, 2008 at 9:39 AM, norman wrote:

Thank you very much indeed for the comprehensive and interesting way you have dealt with my original question. I have no doubt that using layers in GIMP coupled with the use of layer masks and curves gives a far superior method of converting colour to black & white. However, I do like to try as many methods as possible as part of the learning curve. Sometimes an old procedure gets over looked simply because it is old.

Norman