Elements and Channels

[Andrew B.]

Hi Richard. I was just in discussion with someone about Elements and Channels and I remembered your tools and techniques. What kind of interface can someone put on Element's Channels.
Can you do things like apply highpass, threshold, contrast, or other filters to channels. Can you switch into a cmyk mode to see if one of those channels makes the beginning of a good mask, and then copy it to an alpha channel.

BTW, I realize that most users will never need to do any of this. I'm just trying to get a feel for how far the channels can be taken.

[Dave Likes]

Confused about Mixing

I also am trying to use the Channel Mixing to color correct too much red in faces--I sometimes get from scanning 35mm negs.

The book explains how--but not in detail?

How would I use channel mixing to fix this? Step by step?

Thanks,

Dave

[Andrew B.]

Hi Dave.

I can't think of any situations where I've used channel mixing to correct that kind of problem.

Why don't you post an example of the problem. Then people can run tests and see what works. Also, is this something that can possibly be controlled at the scanner step. Or is this just some odd random thing that happens?

[Dave Likes]

Hi Andrew,

I can't seem to get the IMG code to turn on in order to post this image. But I've enclosed a link to it. Note that their is too much red in the faces yet not enough red in the women's dress?

This image was scanned using my Nikon Coolscan IV-ED 35mm film scanner. It is kodak portra 160 VC film. The scan may be slightly underexposed by 1/2 stop.

My feeling is that it was something wrong with the film or developing? As I normally get great scans with my Nikon? Just about 1 in 20 do I get a problem scan like this one.

http://home.infi.net/~ldlikes/redgroup.jpg

Dave

[Richard_Lynch]

Andrew,

The way channels break out in layers, you can actually control them more easily than you would normal Photoshop channels. the reason for this is because you can do anything to the channels in the layer palette that you would to a normal layer but the result effects the channels. Quite honestly I use the technique I have in the Elements book when working in Photoshop (actually, one very similar) because it is not always so straight-forward to apply filters or more, adjustment layers and such to specific channels. Of course you can, by activating just one channel, but I actually find the layered channels easier to use -- there are no tricks to getting a full-color preview of the results.

If there is something you find that you can't seem to accomplish, I'd be glad to help solve that for you.

[Richard_Lynch]

In testing corrections of that image, I had much more inclination to add yellow using the Color Balance than to remove red (which seemed to desaturate the image). I would give a go with color balance before anything else (well, beside the initial correction, of course).

You can use the Channel Mixer, but I think I might do that in combination with something else. In fact, you might want to try a color range correction using Blend Masking...I don't advocate channel mixing too much in the book for working with skin tone...That isn't to say it can't be done.

[Andrew B.]

>>If there is something you find that you can't seem to accomplish, I'd be glad to help solve that for you.

I don't have Elements loaded, I'm only trying to understand the channels interface in Elements because of a discussion I am in.

In Photoshop I generally copy the channel into a layer. Then point that layer at the channel it came from. Once this is done I can do whatever I want to it and see a live preview as I work, all in a nondestructive way.

Is this how you are working in Elements?

There is another area as well. Channels can be used to make masks. So here I would not point the copy back at the channel, I would work on it until it makes a good mask. Then copy it into a new alpha channel, and load it whenever I want to.

Are you able to create alpha channels from layers and then call them up as needed? What is the interface like?

[Susan S.]

Andrew - Richard's interface for seeing the different channels in Elements uses a large number of steps (involving HUE/Satuaration adjustment layers as filters to filter out the individual colours) to create greyscale version of each channel appearing as separate layers on a PE2 document. The channel layers can then be recombined to see the effects of individual edits on the channels again using Hue/saturation layers as filters. To do this by hand takes an inordinate number of steps, but Richard gives purchasers of his book a one click action that does it for us.
These channel layers can be used to make masks - but as PE doesn't have native layer masking Richard's book suggest using clipping groups to use these edited channel layers as masks - this also makes them easier to save for PE1 users who don't have the ability to save selections (alpha channels) unlike PE2. One of Richard's new tools gives the ability to add layer masks, but as I've generally got into the habit of using clipping groups anyway, I haven't yet explored this feature much.

[caseyJ]

Save Selection

Andrew;
PS Elements 2 has a "save selection" option under Select. The selection can be given a name and then be reloaded at any time by the "load selection" option also under select. More than one selection can be saved. If no longer needed or wanted it can be deleted "delete selection" also under select. Elements does not have the alpha channel layer such as the full Photoshop but selections can be saved, and even saved with the image file as a PSD and reopened and reloaded at any time. The selection can be copied and pasted or adjusted however you wish. I hope this is the information you were looking for. CaseyJ

[Andrew B.]

Thanks for the info. I'm getting a much better idea now.

I'm still unclear on one thing. In Photoshop you can create your mask on a layer, then move it to an alpha channel, then load it as a selection. I am not talking about a layer mask, I am talking about using a layer as sort of the work bench where you shape the mask for later use.

I guess the bottom line question is can you take the grayscale mask that you create on a layer and convert it to a marching ants selection that exactly matches the luminosity variations of the mask.

And btw, I hope it doesn't sound like I'm nitpicking on these methods. I think it's fantastic that Richard has found such a low-cost way to bring so much power to Elements. I only want to get a better idea of how this works.

[Susan S.]

Andrew - yes - it is certainly possible - with a bit of tweaking and pulling around. Richard has a one click tool that can do this. The way I have done this in the past is from a tutorial on Jay Arraich's very useful Element's website and involves using a layer mask as an intermediate (before the add-on tools I used the layer mask in a temporarily added adjustment layer).

Select and copy the greyscale layer: paste into the layer mask; deselect; command-click (I'm on a Mac - control click for Win I guess) on the layer mask thumbnail to load the mask as a selection; then save the selection which can then be loaded into whatever layer you like. I haven't checked whether this gives an identical result to Richard's.
Susan S.

[Andrew B.]

Thanks Susan. All my questions are answered.

[Dave Likes]

Andrew,

Thanks for trying to correct the color in my image. Your adjustment, using levels, was what I initially did. I had my pro lab print the image. I'm a wedding photographer. Turned out that the skin tones were still too muddy! The red dress was off red. And my blue background had turned green!!!

After many hours of manipulation, using scanner techniques (1/2 stop analog gain in Nikon scan), using Elements the hard way. Selecting the dress, and background individually (using lasso tool, and color saturation) I came up with this improved image (see link).

I'm just looking for a better/easier way? If that is possible? I also would like to know why the image did not scan properly? I did not have channels or some of Richard's tools for Elements prior to fixing this image by brute force!

Dave


http://home.infi.net/~ldlikes/redgroupb.jpg

[Susan S.]

Wow! Dave - that is a very red dress! Perhaps the scanner just didn't believe the colour when it saw it . I had a go at the image as a practice for using the techniques given in Chapter four of Richard's book and used curves on the individual channels - and in general found that the channels did not need much tweaking to get the face tones cleared up and the blue background un-greened. But that correction did not bring the red dress up to anything like *that* colour red - it remained firmly dark-peach whatever I did to the other channels, keeping the flesh tones within reason.
Susan S.

[Richard_Lynch]

I could just be seeing things, but it looks like that second version of the image was not the natural color of the dress. I am guessing this by the detail loss in shadowing and texture. It is not a bad result, but there are better and worse ways of getting there.

Something that you might try is using a Luminosity layer created from the image after the innitial adjustment.

1. finish your general color correction.
2. duplicate the layer
3. desaturate the layer (if you have hidden power, you can just click Add Luminosity).
4. insert another layer between the original and the luminosity layer.
5. paint over the dress with the color of your choice on that layer.
6. experiment with a few of the modes, like color burn, overlay, pin light and linear light. The opacity for this layer is probably best at 25-50%. Note I did NOT say to use Color mode. In my experience, it is usually not the best idea for recoloring information.

I used that to get the results here:

http://hiddenelements.com/samples/redgroup2.jpg

Judging from your sample, this may appear over-saturated. If so, one of us needs to recalibrate -- and it could be me. I've been playing with a lot of things recently, and not all of them have been nice to my configurations.

I still think exploring the Blend Mask function will get the best result over-all in Elements as it will be better at targeting the color for change.