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...