James Ritson

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Photo FAQs Answered With Tutorials

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Hi

I have done a bit of a search but can't find what I am looking for so I thought I would ask.

I am a long, long, long time Photoshop user (25yrs+) but have begun using AP for a variety of reasons. So lots of UN-learning to do. O.o

I have watched most of the tutorials I can find on "Channels" but can't seem to do what I want, which is of course frustrating because I can do it in PS in my sleep.

What I am trying to do is "Channel Chopping" i.e. copying and pasting channels to alter colour and tonality.

By way of example, editing a tomato, in CMYK it may lack definition and shape after conversion from RGB as the M and Y channels would be saturated. To add shape and form you would look at the individual channels and perhaps copy the C channel and paste it into the K (within a selection of course) to increase the shading and restore the "volume".

I can't figure out how to do this in AP. I can see and choose individual channels, but can't seem to copy and paste between them.

 

Any suggestions would be greatly appreciated.

 

Kind regards,

Jason.

 

 

Jason@shoot.co.nz

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Select the CMYK pixel layer on canvas or in Layers panel.

Select the required pixels.

Press Cmd-J to duplicate the selected pixels to a new unnamed pixel layer which will be selected automatically in Layers panel.

Right-click Pixel Cyan channel thumbnail and pick "Create Spare Channel".

Right-click Spare Channel thumbnail and pick "Load to Pixel Black".

Optionally merge down the adjusted layer into the original.

 

 

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3 hours ago, owenr said:

Select the CMYK pixel layer on canvas or in Layers panel.

Select the required pixels.

Press Cmd-J to duplicate the selected pixels to a new unnamed pixel layer which will be selected automatically in Layers panel.

Right-click Pixel Cyan channel thumbnail and pick "Create Spare Channel".

Right-click Spare Channel thumbnail and pick "Load to Pixel Black".

Optionally merge down the adjusted layer into the original.

 

 

Kind of.

Seems much more complicated and convoluted than it needs too be, creating extra layers and channels. Why can't you just select and view individual channels easily, and copy and paste directly between them, without having to create all the extra stuff?

Will work, but needs work, if you know what I mean.

 

Cheers,

Jason.9_9

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12 minutes ago, photo570 said:

Kind of.

Seems much more complicated and convoluted than it needs too be, creating extra layers and channels. Why can't you just select and view individual channels easily, and copy and paste directly between them, without having to create all the extra stuff?

Will work, but needs work, if you know what I mean.

 

Cheers,

Jason.9_9

 

Yes, it's ridiculously convoluted. Can only hope that it will be improved within a few years.

 

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Hello James, I have found your videos very useful as I am very new to AP and never an advance PS user. 

 

Can anyone share what is the most accurate method to remove the colour cast caused by a Lee Big Stopper or other ND filters? Is there a video tutorial for it?

 

From what hat people have asked in the forum and what I can figure out, my options are the WB sampler tool, WB adjustments in RAW and HSL? 

 

Any advice and help will be appreciated, thanks in advance. 

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On 11/5/2017 at 2:22 PM, photo570 said:

Seems much more complicated and convoluted than it needs too be, creating extra layers and channels. Why can't you just select and view individual channels easily, and copy and paste directly between them, without having to create all the extra stuff?

I don't have much experience working with color channels in AP & quite possibly I do not understand what you are trying to do, so with that in mind would the following work as an alternative to copying and pasting channels?

 

1. Make any selections as needed.

2. In the Channels panel, make only the composite channel of interest editable, for example Composite Black.

3. Add an adjustment layer, for example Brightness Contrast or HSL.

4. Change the adjustment layer settings to get the tonal effect you want.

 

I experimented with this approach & it seems to be simple, very flexible, & most importantly non-destructive. 


Affinity Photo 1.6.6; Affinity Designer 1.6.0; AP for iPad 1.6.2 (but no supported iPad -- yet!)

macOS High Sierra 10.13.2; iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM 

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3 hours ago, R C-R said:

I don't have much experience working with color channels in AP & quite possibly I do not understand what you are trying to do, so with that in mind would the following work as an alternative to copying and pasting channels?

 

1. Make any selections as needed.

2. In the Channels panel, make only the composite channel of interest editable, for example Composite Black.

3. Add an adjustment layer, for example Brightness Contrast or HSL.

4. Change the adjustment layer settings to get the tonal effect you want.

 

I experimented with this approach & it seems to be simple, very flexible, & most importantly non-destructive. 

 

Simple, very flexible, non-destructive and completely irrelevant. photo570 wants to copy one channel to another channel.

 

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4 hours ago, owenr said:

Simple, very flexible, non-destructive and completely irrelevant. photo570 wants to copy one channel to another channel.

I understand it is not what @photo570 wanted to do, which is why I suggested it as an alternative, one that might offer some advantages to the (to me, anyway) rather stark results copying & pasting color channels often creates.

 

Thus, I do not consider it irrelevant.


Affinity Photo 1.6.6; Affinity Designer 1.6.0; AP for iPad 1.6.2 (but no supported iPad -- yet!)

macOS High Sierra 10.13.2; iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM 

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1 hour ago, R C-R said:

I understand it is not what @photo570 wanted to do, which is why I suggested it as an alternative, one that might offer some advantages to the (to me, anyway) rather stark results copying & pasting color channels often creates.

 

Thus, I do not consider it irrelevant.

 

OK, fair enough, but I don't understand why you're making only one composite channel editable since that makes no difference to the output of an Adjustment layer. am I missing something?

 

 

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7 minutes ago, owenr said:

... but I don't understand why you're making only one composite channel editable since that makes no difference to the output of an Adjustment layer.

At least on my system, it makes a difference for some adjustment layer types but not others. I don't know why.


Affinity Photo 1.6.6; Affinity Designer 1.6.0; AP for iPad 1.6.2 (but no supported iPad -- yet!)

macOS High Sierra 10.13.2; iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM 

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24 minutes ago, R C-R said:

At least on my system, it makes a difference for some adjustment layer types but not others. I don't know why.

 

None on my system. Maybe you've broken something :D

 

 

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1 minute ago, owenr said:

None on my system. Maybe you've broken something :D

Maybe, but check out the attached Ec flower.afphoto file. I included a "flower selection" spare channel for convenience -- you can load that to the pixel selection if you want to try to duplicate my results.

 

The original photo, the Brightness Contrast adjusted results, the HSL adjusted results, & the results with both adjustments are shown below:

original.png.1c8d81e27f16d6506ffb11468ee247a6.png 5a0b74a66c874_BrightnessContrast.png.de03ecbb0e0e6f681d31b6ba7bae2e8b.png

HSL.png.c678fdc0cdc7511e66c1454d7333a43d.png Both.png.7fede7509fb67c5a2340813538e31f55.png

Both adjustments were applied with only the Composite Black channel editable on the pixel selection. They can both be non-destructively adjusted with just that channel editable, or to get different results use some other combination of composite channels made editable. 


Affinity Photo 1.6.6; Affinity Designer 1.6.0; AP for iPad 1.6.2 (but no supported iPad -- yet!)

macOS High Sierra 10.13.2; iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM 

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15 minutes ago, R C-R said:

[...] or to get different results use some other combination of composite channels made editable. 

 

No difference on my system, and that's what I'd expect because an Adjustment layer doesn't edit pixels, so the editability of each composite channel should have no bearing on the output of the Adjustment layer.

 

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4 minutes ago, owenr said:

No difference on my system, and that's what I'd expect because an Adjustment layer doesn't edit pixels, so the editability of each composite channel should have no bearing on the output of the Adjustment layer.

So if you download & open my Ec flower.afphoto file, & toggle on & off the two adjustment layers without doing anything else, do you get the results I showed in the screenshots or something else?

 

Or if you use the "flower selection" spare channel to set the pixel selection, enable editing only for the Composite Black channel, & change the settings of either the HSL or Brightness Contrast adjustments, do you see that affect anything other than the composite black channel?


Affinity Photo 1.6.6; Affinity Designer 1.6.0; AP for iPad 1.6.2 (but no supported iPad -- yet!)

macOS High Sierra 10.13.2; iMac (27-inch, Late 2012); 2.9GHz i5 CPU; NVIDIA GeForce GTX 660M; 8GB RAM 

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5 hours ago, R C-R said:

So if you download & open my Ec flower.afphoto file, & toggle on & off the two adjustment layers without doing anything else, do you get the results I showed in the screenshots or something else?

 

Same as you.

 

5 hours ago, R C-R said:

Or if you use the "flower selection" spare channel to set the pixel selection, enable editing only for the Composite Black channel, & change the settings of either the HSL or Brightness Contrast adjustments, do you see that affect anything other than the composite black channel?

 

All 4 colour channels are affected for me.

 

5a0bd8417f578_ScreenShot2017-11-15at05_50_00.thumb.png.f4b78f2e61557ebdee647791c4cfc520.png 

5a0bd83b5aadd_ScreenShot2017-11-15at05_50_45.thumb.png.6407c854b75e634de5ada1f2b8825500.png 5a0bd8350d2ff_ScreenShot2017-11-15at05_51_15.thumb.png.67532ea0c83251dc39e035f582ad3b9a.png

 

 

 

 

 

Edited by owenr
Added images

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Sorry,

I have been away for a while and not looked in on this thread. Thanks R C-R But not at all what I am trying to do. "Channel Chopping" is an old technique where you take the tonal information from one channel, copy it and then paste it into another channel to drastically change the colour. The benefit of doing this as opposed to using something like selective colour or hue saturation is that preserves detail and texture. With SC or HS, if you make huge colour changes, eg red to blue you loose contrast in the individual channels, and therefore everything flattens out and looses "Shape"

 

I have bought the workbook, should arrive soon (shipping to New Zealand O.o) hopefully that will have some clues in it.

 

Thanks,

Jason.

Edited by photo570
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10 hours ago, photo570 said:

Sorry,

I have been away for a while and not looked in on this thread. Thanks R C-R But not at all what I am trying to do. "Channel Chopping" is an old technique where you take the tonal information from one channel, copy it and then paste it into another channel to drastically change the colour. The benefit of doing this as opposed to using something like selective colour or hue saturation is that preserves detail and texture. With SC or HS, if you make huge colour changes, eg red to blue you loose contrast in the individual channels, and therefore everything flattens out and looses "Shape"

 

I have bought the workbook, should arrive soon (shipping to New Zealand O.o) hopefully that will have some clues in it.

 

Thanks,

Jason.

 

I have realised there is a direct method using Apply Image filter.

 

Select the relevant pixel/image layer in your CMYK document

Open Filters > Apply Image dialog:

  1. Use Current Layer As Source
  2. Equations
  3. Equation Colour Space: CMYK
  4. Change the DK field to "SC" (without quotes)
  5. Apply

 

5a1ab9c6708a1_ScreenShot2017-11-26at12_50_33.thumb.png.2d907e13de12cfbde38f393f0c5baafb.png

 

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Thanks Owenr.

Will this work within a selection? If so then it may just accomplish the same effect as "Channel chopping" Yay!

Will have to give it a try over the next few days.

The work book has arrived, and I am slowly working my way through it. Soooooo much Adobe to unlearn. It is a real struggle for me, as I have been using PS for nearly 30 years and don't really think about what I am doing, it is all just automatic.

 

Kind regards,

Jason Berge.

 

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