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Greyscale to Transparency : how to ? [Solved]


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Hi,

 

I have a greyscale image that i want to use as alpha channel for another layer (well, the same, in fact).

This would take me 2 seconds in PS : invert layer, copy, select alpha channel, paste, done.

 

I struggled in Affinity for more than an hour, search tutorials, watched videos... no way. Can't figure it out. I just can't paste anything in the Alpha channel. Not even in a layer mask, but that's not waht i want anyway...

And i dropped PS for Affinity...

(honestly, i just love Af Design, but just don't get Af Photo, it's... bah, i don't get it...)

 

Help, please ?

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Several ways, depending on what you want it for but this might do it. I have found several ways to do a similar thing but i'm still learning.

 

Right click on the appropriate Channel of the Pixel Layer Channel (not composite), called background? Create greyscale layer.

 

Select the grey layer, adjust contrast, levels etc etc. 

Filter - Colours - Erase White Paper.

Right click on the grey layer and select Mask to Below. You might have to invert it first?

 

Voila, a mask on the Alpha. Not 2 seconds but under 30 seconds. 

Windows PCs. Photo and Designer, latest non-beta versions.

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Mmmh... Thanks for your reply, but, really ?

 

So : 

- Duplicate layer

- Invert

- Rasterize to mask

- Drop as Mask on original layer

- Add Level adjust layer, because greys are not really transparent, there's white in it.

- Drop on original layer

- Adjust levels so the white goes out

- Fusion (sorry, french version here...)  the layers to get a transparent layer alone

 

Wow. 

It does work... Somehow.

 

But... Really no way to simply paste greyscale image on alpha layer ?

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Voila, a mask on the Alpha. Not 2 seconds but under 30 seconds. 

 

Yeah, thanks.

You're both kind to have taken time to reply, but i find the solutions quite cumbersome, sorry... 

Again, why is it impossible to paste anything directly on alpha channel ? That's really strange...

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Mmmh... Thanks for your reply, but, really ?

 

So : 

- Duplicate layer

- Invert

- Rasterize to mask

- Drop as Mask on original layer

- Add Level adjust layer, because greys are not really transparent, there's white in it.

- Drop on original layer

- Adjust levels so the white goes out

- Fusion (sorry, french version here...)  the layers to get a transparent layer alone

 

Wow. 

It does work... Somehow.

 

But... Really no way to simply paste greyscale image on alpha layer ?

you can actually create a macro to do it in one step/ klick

 

the levels adjustment would be a separate step in your ps workflow just the same

 

 

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Mmmh... Thanks for your reply, but, really ?

 

So : 

- Duplicate layer

- Invert

- Rasterize to mask

- Drop as Mask on original layer

- Add Level adjust layer, because greys are not really transparent, there's white in it.

- Drop on original layer

- Adjust levels so the white goes out

- Fusion (sorry, french version here...)  the layers to get a transparent layer alone

 

Wow. 

It does work... Somehow.

 

But... Really no way to simply paste greyscale image on alpha layer ?

 

Well, that included adjustments to the grey channel. I assumed you wanted to edit it, like channel masking.

 

Right click, greyscale layer, colours - erase paper, mask to below

 

Thats just three clicks, how is that much worse than PS? How long does it take you to make one click?

 

There are other ways but I think they all involve 3 clicks, sorry. And as MBd says, you could make a macro, then it's only one click!

 

If I find a way with two clicks I'll let you know. Sure AP is not as good as PS at some things but it's better at others and costs a fraction of the price.

Windows PCs. Photo and Designer, latest non-beta versions.

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Still three clicks but if after "Erase paper" you use "erase" in the greyscale layers blending mode, you can adjust opacity to vary the effect.

Windows PCs. Photo and Designer, latest non-beta versions.

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Sorry if that sounded harsh to you, that was certainly not the purpose. Again thanks for helping.

 

It's indeed a bit more than three clicks, your turn to being not that objective  :)  .

Alpha layers being just greyscale images, using one without any other manipulation seems very obvious to me, that's why i don't understand the impossibility to do so in Af... I used about 2% of PS, so i switched to Af with joy, but i just find out that the rare Af flaws are just in my 2%... gasp.

 

It is quite bothering me because i have plenty of image to process this way, and this is something i do very often. Three clicks by hundreds...

 

And again, i can draw on alpha channel, but not paste any copied pixels... Isn't it stupid ?

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Yes, it is a feature I'd like to see, if only because it would help the migration of us long term PS users. Using channels is quite common. I have come across a few others too, some like this I have found a workaround, some not. I must admit, I had to do one quick image for someone a few days back and reverted to Photoshop. I feel so ashamed  :(

 

I once created a 9 channel file for tee shirt printing.

 

If you do have to do a lot, go for the one click macro!

Windows PCs. Photo and Designer, latest non-beta versions.

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Gep,

 

I am not sure exactly what you want to do but if it is just to use a greyscale image as a transparency mask for another layer, have you tried this:

 

1. In the Layers panel, make sure the greyscale image layer is above the other layer.

2. Select the greyscale image layer & from the Affinity Photo Layers menu, select "Rasterize To Mask."

3. If desired, invert the layer.

4. Optionally, drag the mask layer into the masking position in the Layers panel (or right click on it & choose "Mask to Below").

 

Only the first two steps are essential -- everything else is optional.

 

This also works with color images, since Rasterize To Mask converts them to greyscale.

Affinity Photo 1.10.5, Affinity Designer 1.10.5, Affinity Publisher 1.10.5;  2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.5.280 & Affinity Designer 1.10.5 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Ha!

 

In Affinity Photo

1 Right click on the channel you want

2 Click on create mask layer

3 Drag that to the layer below

 

 

In Photoshop

1 Click on the channel you want

2 Ctrl C

3 Click on the Alpha

4 Ctrl V

 

And how do you Ctrl C and Ctrl V ? add two more (right) clicks to bring up the menu, move your left hand to click (press) the modifier keys both times (I make that 6 clicks) or go all the way up to the edit menu?

Not only is Affinity photo less clicks, you can do it all within a small focused area and it is totally non destructive.

 

That's er,  :unsure: 17.8% more productive ?

 

Actually, with practice it should be almost twice as fast which is 62% ;)

 

Anyone come up with less clicks ?

Windows PCs. Photo and Designer, latest non-beta versions.

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Alpha layers being just greyscale images, using one without any other manipulation seems very obvious to me, that's why i don't understand the impossibility to do so in Af... 

This may help you understand how it works in Affinity Photo:

 

An alpha channel is actually just a mask stored as a greyscale image. (See for example the "About masks and alpha channels" section of the Save selections and alpha channel masks Photoshop User Guide page.)

 

An ordinary ("flat") image file opened in Affinity Photo has just one alpha channel that determines its opacity. For a JPEG file, it is completely opaque (100% white) since the JPEG format does not support transparency; a PNG file may or may not include transparency, so it might have a 100% white, totally opaque alpha channel or one with greyscale values. If the AP document has multiple pixel layers, each layer will have its own alpha channel that determines its opacity.

 

So for example, if you have added a greyscale image to an AP document as a new layer & all parts of it appear opaque (nothing from a layer below it shows through) then its alpha channel is completely white, regardless of the grey levels in its other channel(s). In other words, the alpha channel mask is not the same thing as the greyscale image itself.

Affinity Photo 1.10.5, Affinity Designer 1.10.5, Affinity Publisher 1.10.5;  2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.5.280 & Affinity Designer 1.10.5 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Toltec : Haha, ok i surrender.

I actually had to reinstall PS to double check, thanks,..

AF : 1 point.

 

R C-R : Thanks for the explanations, even if i already quite understand how channels work : i'm making images all day long (which are so perfect they don't need PS or AF, haha ! ...hem.)

 

The confusion is all my fault : i work on images which already have an alpha channel, thus the copy and past process. Indeed, if there is no previous alpha, you have to create a mask to make one...

 

Thanks for your help, case closed.

Now uninstalling PS again...

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Ha!

 

In Affinity Photo

1 Right click on the channel you want

2 Click on create mask layer

3 Drag that to the layer below

To be a bit pedantic about it, you left out step zero: click on the layer in the Layers panel to select it (or click on it in the workspace with the Move tool or whatever). Otherwise, you won't see that layer's channels in the Channels panel or be able to right click on any of them. If no layer is selected, all you you have to work with in the Channels panel are the document's composite channels, & there is no "Create Mask Layer" option for them.

 

But more importantly (for those following this topic who don't already know this), in Affinity Photo every pixel layer already has its own alpha channel, in addition to whatever other channels there are in the document's color space ("Color Format" in AP terminology) -- one other for Greyscale, three others for RGB or LAB, & four others for CMYK. Because alpha channels are really just colorless masks stored in image files as greyscale images, if the source file has an alpha channel, AP will use that; otherwise it will create an alpha channel that masks the entire layer, stored as a 100% white greyscale image.

 

So for example, if the source file is a jpeg it has no alpha channel, so in AP's Channels panel it will appear as an all white rectangle the same size as the jpeg file's pixel dimensions. There is usually no reason to create a new mask layer from that (because it already exists). If all you want to do is make part of or the entire layer partially transparent, you can do that directly on the pixel layer by using an erase brush, by changing the layer's opacity in the Layers panel, etc.

 

It can get confusing because a greyscale pixel layer looks the same as an alpha channel stored as a greyscale image, but they are really two different things. (It took me much longer to figure this out than I like to admit.) So if you want to use a greyscale pixel layer as an alpha channel mask, you have to convert it to that. That is what the "Rasterize To Mask" item on the Layers menu does, & it is a one step process (ignoring step zero as above).

 

Personally, I think it would be less confusing/more obvious if the Layers menu item was named "Convert To Mask" but that is just me.

Affinity Photo 1.10.5, Affinity Designer 1.10.5, Affinity Publisher 1.10.5;  2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.5.280 & Affinity Designer 1.10.5 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Personally, I think it would be less confusing/more obvious if the Layers menu item was named "Convert To Mask" but that is just me.

 

No, it's not just you. There are at least two of us! :lol:

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Affinity Designer/Photo/Publisher for Windows 1.10 • Windows 10 Home/Pro
Affinity Photo for iPad 1.10 • Designer for iPad 1.10 • iPadOS 15.6.1 (iPad Air 2)

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yes, i think i got confused too by this "alpha" channel where i could not paste greyscale pixels...

 

Now i indeed used Rasterize to Mask in a macro and it does the job. Too bad is that i have to do the process in 2 macros because of the inability to record layers move. This i find strange, as AF is very clever in macro's layer selection, offering a bunch of usefull options. I guess it could do so with layers moves... (1 up, 1 down, top, bottom, etc...)

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Gep, you could create a custom keyboard shortcut for the Rasterize to Mask menu item. It would not help with the macro issue but it could speed things up a bit when you manually need to convert a layer to a mask.

Affinity Photo 1.10.5, Affinity Designer 1.10.5, Affinity Publisher 1.10.5;  2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.5.280 & Affinity Designer 1.10.5 for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Personally, I think it would be less confusing/more obvious if the Layers menu item was named "Convert To Mask" but that is just me.

Me four.

 

I didn't even consider using the Rasterize to Mask option for an already rasterized  layer, so found an alternative bodge,

 

Now, had it been a vector image I wanted to make into a mask by rasterizing it.

 

According to the help files

 

Rasterizing

Shape, Line, and Text layers can be rasterized to create raster layers. This "flattening" operation can be performed manually or automatically (when applying filters or retouch brushes).

 

According to an Affinity help search

 

Rasterization

is only a requirement if the appearance of complex vector gradients or effects need to be honoured, particularly for print artwork.

 

Rasterize to Mask

 

 

 

 

 

Somewhat less.

 

Just saying  :)

Windows PCs. Photo and Designer, latest non-beta versions.

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Gep, you could create a custom keyboard shortcut for the Rasterize to Mask menu item. It would not help with the macro issue but it could speed things up a bit when you manually need to convert a layer to a mask.

Doesn't even need to do all that in his case if he right clicks on the channel he wants and selects "Create Mask Layer"

 

I don't see how a macro would help. You have to click on the layer first then it's only one click.

Windows PCs. Photo and Designer, latest non-beta versions.

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Hi Gep,

Welcome to Affinity Forums :)

The command you are looking for is Rasterise To Mask as suggested in the first reply (to convert your greyscale image to a mask). Currently there's no way to paste directly into masks in Affinity. This was requested a few times already and may end up being added to the program in a future version.

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In fact my original calculation of three clicks was grossly overestimated. Sorry AP

 

Right click on the channel you want

Select Create Mask Layer

 

That's it, done.

 

That is precisely half the number of clicks needed in PS.

 

If you want to get it there permanently in the Alpha (no mask layer) just merge in down.

 

That might take a couple more clicks  :D

Windows PCs. Photo and Designer, latest non-beta versions.

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Yes, the only difference is that "create mask" keeps the original layer.

 

Anyway, i need a macro because the wanted result is a little bit more complex :

 

macro1

- open greyscale image

- invert

- rasterize to mask (or create mask,but i'll have to delete the original layer anyway)

create new layer

fill with black

 

- end of macro 1 because of inability to change layer order

- put mask layer above black one

 

macro2

- Fuse visible layers (don't know the proper name in the english version)

- Rename

- Select underlying layer

- Delete x 2 (black layer and mask)

- Change mode to RGB

 

There i have a transparent layer ready to be used in my final image.

(for info, it is to convert a B&W Ambient Occlusion file into a transparent layer, AO files being special shadows from 3D renders. It's usually used in Multiply mode, but my clients are Art Directors, you know... the kind of guys that ask for 4x3 meters street ads files at 300 dpi...Haha, sorry, i guess there's plenty here...)

 

About the rasterize thing, i don't always understand either, because AF seems to rasterize Pixels layers for some effects... -> ? 

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Hi Gep,

Welcome to Affinity Forums :)

The command you are looking for is Rasterise To Mask as suggested in the first reply (to convert your greyscale image to a mask). Currently there's no way to paste directly into masks in Affinity. This was requested a few times already and may end up being added to the program in a future version.

Thanks Meb.

Yes, would be nice, this and the ability to move layers within macros...

 

Hey, i'm moving to Lisbon with friends tonight for a few days. Have any unknown nice place to go ?

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