Copying and pasting into/out of channels more intuitively

[ateleman]

I'm used to using Photoshop where I find that some of these manipulations mentioned below were solved more intuitively, and wonder if this could be improved in Affinity Photo (which is great!):

I'm a scientist, and often obtain several single-channel/grayscale images from a CCD camera or a microscope (ie an 8-bit grayscale image), which I then need to combine into a single RGB image. So basically I start with two grayscale/single-channel images and I want to put one into the green channel of an RGB image, and  the other into the blue channel of the RGB.

With Photoshop, it was easy: I would first convert one of the grayscale images into an RGB. Then I would click on the other grayscale image and 'copy' it. Then I would go back to the RGB image,  select the red channel and delete (because in  this case, for instance, I don't need it), then click on the blue channel, 'paste', and be done. (ie the copied grayscale image would be pasted into the blue channel only).

This approach does not seem to work in Affinity photo. Instead, I found the following solution:

1. open the two single-channel TIFF files in affinity photo

2. convert one to RGB by going to Document > Convert Format / ICC profile and then select RGB/8 as the color format

3. click on the ‘Channels’ panel. 

4. Select the channel you want to delete (e.g. Composite Red), then use the markee tool to select everything,

and hit the delete key. (Selecting everything with “Select All” / Command-A will cause everything to be deleted).

5. Go to the other file containing the grayscale image that you want to paste into one channel of the RGB image,

copy, then go to the RGB, click on “Layers” and paste. This should create a new layer with a black & white version

of the channel you want to add.

6. Make sure you select this new layer in the ‘layers’ panel, then click on ‘channels’, select the channel you want (e.g. blue),

right-click and select “create spare channel”.

7. Go back to the ‘layers’ and delete the new layer that you added in step 5

8. Go back to ‘channels’, right-click on the spare channel (which is still there after deleting the original layer)

and select ‘load to Background blue’.

9. In the upper right corner of the ‘channels’ panel is an arrow that goes around in a circle. Click on this to ‘reset’

and see all the channels.

Since I am fairly new to AP, there might be a faster/easier way to do this? If so, I would be happy to hear about it !

Otherwise, I would suggest the following change to make it more intuitive to work with channels: if I select only one channel  for editing, then all copy/paste/delete operations should apply only to this channel. (Otherwise, what's the point of having the other channels not selected for editing?)

Currently, in AP, the following things seem un-intuitive:

1. if I select only one channel for editing (e.g. "Composite Red") and do "Select All" and hit delete, then the entire layer gets deleted (ie all three channels), rather than only deleting the information from the red channel. The work-around for this currently is that selecting everything with the markee, rather that saying 'select all', works.

2. if I have only one channel selected, and then click 'copy', for some reason the entire layer (ie all three channels RGB) gets copied into the clipboard. Instead, I would suggest that if only one channel is selected, then only the information from that one channel should be copied, yielding an 8-bit grayscale image in the clipboard.

3. if I have only one channel selected, and I paste from the clipboard a single-channel 8-bit grayscale image, then for some reason this image gets pasted into all three channels. I would suggest that the data from the single-channel image in the clipboard should only go into the single selected channel.

I think these changes would make it much easier to both split channels and combine channels to make RGB images...

 

Thanks !!

 

[ImreLovasz]

I completely agree, Select All / Delete acting on invisible channels almost melted my brain :-(

Dealing with layers/channels are quite counterintuitive at the moment, and the ideas outlined above would greatly improve the workflow. I think a lot of image processing op should be selection and visibility aware. For example, if I'm about to paste a grey scale image when two channels visible, I'd expect to paste the image into both visible channels. Or, pasting an RGB image into a single channel should pop up a dialog asking whether I want to paste a specific channel or lightness (or even more options), etc.

Cheers,
Imre

 

 

[loukash]

On 2/3/2021 at 1:01 PM, ateleman said:

there might be a faster/easier way to do this? If so, I would be happy to hear about it !

For me, this task is a completely new territory in general, even after using Photoshop since the mid-1990s and Photo since 2015. Never done stuff like this before.
But after experimenting with the available tools for, say, 10 minutes, once you know where to click and what happens when you do, it seems quite easy to me.
Here I'm actually taking an existing RGB image, splitting it into separate channels first, and then merging back to RGB.
(For some unknown reason, the thumbnails in the Layers panel don't always update immediately)

[loukash]

A lunch break brings new ideas…
Here I'm starting with three grayscale layers placed on top of each other in a grayscale document:

[loukash]

Another method:

[loukash]

The above FX method even faster via macros:

[loukash]

So many possibilities…
The FX method 100% non-destructive:

[ImreLovasz]

Excellent, thanks a lot for these, loukash!

It was pretty frustrating to realize a 3 minutes task might take much longer because the tool doesn't work as expected.

Cheers,
Imre

[ImreLovasz]

Hi,

So, I've checked the videos and there are a few nice tricks up Affinity Photo's sleeve, indeed 🙂

However, sometimes we just want to fix a few things, and the first video demonstrates that some simple tasks require (unnecessarily) convoluted workflow.

Cheers,
Imre

[ateleman]

Dear loukash,

Thank you ! That is very helpful  !!

[loukash]

4 hours ago, ImreLovasz said:

sometimes we just want to fix a few things

What do you mean by "fix a few things"? Give us an example.

4 hours ago, ImreLovasz said:

the first video demonstrates that some simple tasks require (unnecessarily) convoluted workflow.

That's a workflow –actually two workflows – for 1) splitting an RGB image into composite gray layers (easy peasy), and 2) a slightly overcomplex method to clean them up to be true R/G/B channels. But 2) also demonstrates what tools are available for channel editing, and those could be useful in other scenarios I haven't even explored yet.

Whereas my other examples show that for this specific task as requested above – "start with two grayscale/single-channel images and […] put one into the green channel of an RGB image, and  the other into the blue channel of the RGB" – there are other, more straightforward methods that will also do exactly what you want.

[ateleman]

I think that what ImreLovasz means is that, although the approaches you showed in AP work well, and I'm grateful for that (I'll be using them a lot !!), nonetheless it could be a  bit more streamlined/simple. In Photoshop,  if I want to copy a region in a picture from only 1 channel, it only takes 3 clicks: 1) I select the channel,  2)  I mark the region I want to copy,  and 3) I press command-C. Done. With AP, I need to first create a grayscale layer from the channel. It's a bit more cluncky,  but not much. (Plus, logically, what's the point of being able to select a single channel if then the actions you do are not restricted to that channel?) But as I said, the current solution works...

[loukash]

6 minutes ago, ateleman said:

if I want to copy a region in a picture from only 1 channel, it only takes 3 clicks: 1) I select the channel,  2)  I mark the region I want to copy,  and 3) I press command-C. Done.

Fair enough, that's less steps.

6 minutes ago, ateleman said:

(Plus, logically, what's the point of being able to select a single channel if then the actions you do are not restricted to that channel?)

Some actions like moving or deleting/cutting a selection from a channel, or painting on a channel are possible:

Others like copying, pasting and duplicating are not. Those always affect the composite image.
Either a bug or a design flaw.

[ambersand]

It's a bit sad that I can edit a channel with the tools, select all in a channel, but neither copy nor paste it to the active edit channel in the same image or another open one.

Let me point out that AP is now very close being able do this, just please enable the paste. Please! (of course a warning might occur if the copy has more bits than the expected 8bit)

The workaround with Spare Channels is just too annoying and wasting A LOT of time.

Also the FX workaround above is not really great.

Edited August 25, 2021 by ambersand

[Mike_A]

I'd  just like to say thank you to loukash for posting those videos - as a new user I'll certainly be studying them.

Nevertheless, the fact that it takes six videos to explain how to manipulate channels seems to suggest that AP needs some serious re-working in this area!

[Menno555]

I am new to AP (day 2 of the trail version) and I like it a lot. English is not my native language, so some things I have to learn.
But indeed the use of color channels is not easy. I use my older Photoshop till now (pre Adobe Cloud) for mainly astrophotography.
So I work also with gray scale images I paste into the RGB channels, especially narrowband. Just simple work, nothing complicated.
But now with AP I can not manage to do that. The videos here and other topics I found do have some work arounds but I don't understand those.
So yes, if a more intuitive way can be made to simply paste into and alter color channels, that would be a huge step forwards

[inediblered]

It's insane that in photoshop this is as easy as CTRL+C CTRL+V and here it's convoluted to the extreme. 

[Samborlang]

Thank you for this. It has been very helpful for my commercial projects. I was able to copy and paste the alpha channel from another image.