Pasting Images Into Alpha Channel

[SlipperyBrick]

Hi,

 

I am looking to do something pretty simple. I want to paste a greyscale image into the alpha channel of another image but for some reason I can't seem to do it. 

 

Each time I paste an image (with the alpha channel of that image selected, it just pastes my image into a new layer.

[Grazie]

Why would you want to?  What is it you finally want to do?

[SlipperyBrick]

Hey,

 

I'm using Affinity Photo for game development and most of the time when I'm dealing with textures I need to pack certain textures in to certain channels.

 

It's ok though after some Googling and YouTube I found a great video that explained how to do it

 

It's so easy in Photoshop but in Affinity Photo once again they have added a slightly more clever way to work

 

 

I love Photo and Designer <3

[giakaama]

Why do this workflow so hard. What's wrong with copy/paste workflow ? The photoshop way . With this workflow we're doing too many clicks for a simple operation .

What's wrong with :

Step 1. Open image

Step 2. Ctrl+A -> Copy Image

Step 3. Select Alpha channel -> Ctrl+V - Paste 

Step 4. Save 

 

 

[MEB]

Hi giakaama,
Welcome to Affinity Forums
Nothing wrong with that (quite the contrary). I do hope there's improvements here in future versions. Affinity Photo is still relatively new. There's quite a few areas that must be looked into/improved/expanded.

[bigbigsimon]

By the way, there are two significant bugs (on Mac at least): 1) you only get the "load to red channel" etc if you right click just below the name of the spare channel. 2) If you want to pack 4 channels, wherever there is a pixel that is 0 in the alpha channel, it turns to black on the color channel, the only workaround I could find was to make this more than 0. Please fix this, I don't want to use photoshop instead .

[Klaus E.]

Maybe someone can create a video that only shows the needed workflow. Then it is much easier to understand.

[Alej]

Has this been implemented already?

I know these posts are from many years ago and found myself in this exact situation. But I wonder if I'm doing it wrong (color, copy merged, paste on the composite alpha) but it just pastes a new layer with what was copied.

Thanks in advance, trying to get away from photoshop little by little.

[Tatom]

Of course they did not implement it. Maybe in 5 years it will be there. Designer still has no pages, although it was promised after the initial release...

Edited February 8, 2021 by Tatom

[IdleJohn]

It's stuff like this which makes it impossible for me to convert to Affinity from Photoshop, as much as I want to 😭

[Tatom]

Same for me.This workflow is a joke. A very bad one, implemented by midwits.

[IdleJohn]

SOLUTION:

1) Paste as new layer, make it the top layer
2) Right click layer > Rasterize to Mask

File > Export

This is a different workflow to what I was used to in PS, but I think it's more flexible because you can optionally have a bunch of layers above or below the mask layer all with their own transparency that will contribute to the final exported alpha channel. ALSO you can have multiple mask layers that all contribute to the final alpha channel.

[Alej]

25 minutes ago, IdleJohn said:

SOLUTION:

1) Paste as new layer, make it the top layer
2) Right click layer > Rasterize to Mask

File > Export

This is a different workflow to what I was used to in PS, but I think it's more flexible because you can optionally have a bunch of layers above or below the mask layer all with their own transparency that will contribute to the final exported alpha channel. ALSO you can have multiple mask layers that all contribute to the final alpha channel.

Solid take, in my experience the photoshop way is a work around to be honest for forcing .TGA files to have the alpha channel (since the exporting is treated completely different if it is .PNG or .TGA there).

The main issue with this though is that sometimes, especially video games, control over the colors where the alpha is zero (or “fully” transparent) is required (premultiplied alpha blending workflows for example). At this point I think it’s better to use something else, .PNG and transparency of the layers (or globally making one like rasterizing to mask with a layer at the very top) works perfectly fine for UI-like assets. For intricate R-G-B-A handling I’m just using substance designer when possible in the end (which also has another set of constraints, like textures there are always power of 2, sometimes a positive, sometimes a drawback). 

[IdleJohn]

One thing I forgot to mention, if you are opening a file that already has an alpha channel that you want to edit, first thing to do is right click Background Alpha > Create Greyscale Layer, then 'remove' the original alpha channel with Background Alpha > Fill

[IdleJohn]

42 minutes ago, Alej said:

especially video games, control over the colors where the alpha is zero (or “fully” transparent) is required

For sure, it's always important to have completely separate alpha and colour. Now with this workflow I can have a layers group for the colour, and a layers group for the alpha. Then all that is required before export is to right click my 'alpha' layer group and Rasterise to Mask.

[crimity]

For the devs: I need this functionality on a daily basis as a technical artist working on games as well as any other artist working with textures on any project I've worked on. I was trying to switch over to Affinity completely when I ran into this issue and had to go back to photoshop. What I'm looking for:

1. Alpha should not have to be transparency. Like in photoshop when you load a TGA, alpha is not considered transparency and when working with some other formats like TIFF it is optional. Photoshops implementation could be better in allowing all formats to be optional on load so with formats like PNG you don't have to go through the main menu bar > Layer > Layer Mask > From Transparency then copy the mask to the alpha channel after loading.
2. Should have a way to quickly select the channel you want to edit and paste or paint directly to it.

Without this I'm stuck in Photoshop land.

[Tatom]

They don't car about this since.... well, they never did. It was also a suggestion for their former product improvement (PhotoPlus).

[SlipperyBrick]

I'm not too sure what the confusion is about. When I originally posted this topic I had no idea how to copy image data into separate channels (a very popular thing to do in game development).

This feature has been around for a long time now in Photo, sure its a few more clicks but there is absolutely nothing complicated about it. You can isolate individual channels, create spare channels and paste those into individual channels, mask individual channels, etc. You have every operation you need to manipulate each individual channel of an image.

Here is a video showing how it is done in Photo.

I'm slightly confused as the feature is completely functional. It works and does what is required. Sure there can be usability improvements, but like I said above, there is nothing complicated about this.

I hope the video tutorial helps people who are looking to apply this to their workflow.

[Tatom]

Nothing complicated?
It was clearly implemented by someone never spent a single minute in the 3D industry.
If I as UX expert were hired to implement to worst and least efficient way of channel packing, I would clearly fail compared to the AF 'implementation'.
It is a bad joke.

But for Crimity:

I made a FilterForge filter for texture packing; if you have FF you could download it and prosper.
Still not PS (that is why I still have PS, it is faster), but helps you to solve this ridiculously unsolved problem.

https://www.filterforge.com/filters/14794.html

[Old Bruce]

4 minutes ago, Tatom said:

It was clearly implemented by someone never spent a single minute in the 3D industry.

Quite possible as this is a 2D application.

[Tatom]

7 minutes ago, Old Bruce said:

Quite possible as this is a 2D application.

Used by 3D artists (or should be used). PS was a 2D application, but it handles alphas perfectly almost since it exists.
So that is not an excuse for anything. If I had no expertise in a field, I would make a research or I would ask someone who has, not to make bad decisions.
Technically it would be pretty easy to make it work with the current - terrible - alpha handling, just some creative mind needed.

[crimity]

2 hours ago, SlipperyBrick said:

I'm not too sure what the confusion is about. When I originally posted this topic I had no idea how to copy image data into separate channels (a very popular thing to do in game development).

This feature has been around for a long time now in Photo, sure its a few more clicks but there is absolutely nothing complicated about it. You can isolate individual channels, create spare channels and paste those into individual channels, mask individual channels, etc. You have every operation you need to manipulate each individual channel of an image.

Here is a video showing how it is done in Photo.

I'm slightly confused as the feature is completely functional. It works and does what is required. Sure there can be usability improvements, but like I said above, there is nothing complicated about this.

I hope the video tutorial helps people who are looking to apply this to their workflow.

Thanks for the video. The main issue I'm experiencing which isn't covered in the video is with how you do the same thing with an alpha channel. Hopefully I'm not missing something but the expectation is to treat Alpha as transparency, right? If so that is exactly what I'm trying to avoid. I was trying to test this just now but ran into an issue I have to take care of some other work.

Also I want to be clear that I think Affinity Photo is amazing. I've only recently become aware of it and was extremely surprised with how much faster it is compared to photoshop. This feedback is not meant as a criticism of the app as a whole but a pain point with this type of workflow. I just hope I'm communicating properly so the AP devs will understand the issue game devs are experiencing.

[SlipperyBrick]

4 hours ago, crimity said:

Thanks for the video. The main issue I'm experiencing which isn't covered in the video is with how you do the same thing with an alpha channel. Hopefully I'm not missing something but the expectation is to treat Alpha as transparency, right? If so that is exactly what I'm trying to avoid. I was trying to test this just now but ran into an issue I have to take care of some other work.

Also I want to be clear that I think Affinity Photo is amazing. I've only recently become aware of it and was extremely surprised with how much faster it is compared to photoshop. This feedback is not meant as a criticism of the app as a whole but a pain point with this type of workflow. I just hope I'm communicating properly so the AP devs will understand the issue game devs are experiencing.

In regards to alpha ... just by you packing some arbitrary data into the alpha channel means that the alpha has a sole purpose of storing data for "something" (this something highly depends on your intentions of how you use alpha). Typically, the use of the alpha channel for game development is completely driven by the shaders/materials employed/designed/programmed by the game engine itself. For instance, I am involved in the development of a commercial 3D game engine and we have shaders in our engine that use the alpha channel for all sorts of things; blending between material layers, masking parts of an image, fresnel factor, etc; alpha is just another channel you can store image data in. Within Affinity Designer though, yes alpha explicitly refers and acts as transparency, if this is what you are talking about then I can see the confusion, but of course this can be ignored as after you export your image from Photo and use it within your game engine alpha will be potentially used for something other than transparency (which seems to be the case as you are explaining that you are using alpha for something other than transparency). 

 

[SlipperyBrick]

6 hours ago, Tatom said:

Used by 3D artists (or should be used). PS was a 2D application, but it handles alphas perfectly almost since it exists.
So that is not an excuse for anything. If I had no expertise in a field, I would make a research or I would ask someone who has, not to make bad decisions.
Technically it would be pretty easy to make it work with the current - terrible - alpha handling, just some creative mind needed.

I have absolutely no clue what you are talking about in regards to Photoshop "handling alphas perfectly", what is the context? Handling them perfectly in what way?

I'd love to get to the bottom of this because I've been subscribed to this thread since I asked the original question a few years back. All I've seen is people have some confusion surrounding alpha, the workflow of manipulating channels in Photo, and in general the overall functionality of handling image data through multiple channels within Photo.

I do agree that a copy/paste approach would be great (similar to Photoshop), but other than that the feature works, it works completely as expected, for both creative approaches and traditional approaches.

[Tatom]

16 minutes ago, SlipperyBrick said:

I have absolutely no clue what you are talking about in regards to Photoshop "handling alphas perfectly", what is the context? Handling them perfectly in what way?

I'd love to get to the bottom of this because I've been subscribed to this thread since I asked the original question a few years back. All I've seen is people have some confusion surrounding alpha, the workflow of manipulating channels in Photo, and in general the overall functionality of handling image data through multiple channels within Photo.

I do agree that a copy/paste approach would be great (similar to Photoshop), but other than that the feature works, it works completely as expected, for both creative approaches and traditional approaches.

I meant the possibility of direct interaction with alpha channel (and all channels - including RGB separately) quickly and directly. And PS does a great job with that; you could copy and paste whatever you want to wherever you want into an RGBA image (per channel level).
Everything is more complicated than that is a bad implementation of channel/alpha handling.

In AP the implementation is a joke. That is why I use PS, waiting for a clever developer hired by Serif.