Add a Dissolve Blend Mode (Feature Suggestion)

[josbin]

I would love to have a dissolve blend mode in Affinit Photo, as Photoshop has. It has some use cases for creating nice and noisy Blurs 😍
Maybe there would be a possiblity to add it to the diffuse Filter, which just diffuses uniformly, not respecting the blur level of the pixels.

Just a Suggestion!

 

[Hughhh]

It needs the dissolve mode. I changed back to PS because of that one feature. So +1 for this request

[NotMyFault]

It is possible to achieve the same effect with help of procedural texture filters.

Can someone please provide example images generated in PS (layer a, layer b, result of blending with alpha of layer a set to  25/33/50/66/75/90%)?

[NotMyFault]

 

[Hughhh]

Thanks @NotMyFault for suggesting this workaround, including producing a video.

The dissolve mode is often used by illustrators in combination with a soft brush setting to paint a “hard” gradient.

Its just a convenient way to produce that kind of effect; so I guess a workaround will not be the solution to many.

I haven’t tried your suggestion nor am I a technical person, but the dissolve mode when used with a soft brush produces a kind of dithering similar to bitmap, since Affinity has stated they won’t include bitmap capabilities in AP, I am somewhat not expectant to see this implemented anytime soon.

But I’m willing to be put right, bc I think AP is great software.

Thanks again

[NotMyFault]

32 minutes ago, Hughhh said:

Thanks @NotMyFault for suggesting this workaround, including producing a video.

The dissolve mode is often used by illustrators in combination with a soft brush setting to paint a “hard” gradient.

Its just a convenient way to produce that kind of effect; so I guess a workaround will not be the solution to many.

I haven’t tried your suggestion nor am I a technical person, but the dissolve mode when used with a soft brush produces a kind of dithering similar to bitmap, since Affinity has stated they won’t include bitmap capabilities in AP, I am somewhat not expectant to see this implemented anytime soon.

But I’m willing to be put right, bc I think AP is great software.

Thanks again

Could you provide an example document (PNG export) showing the effect? you mention many topics who are probably well known in the Photoshop universe, but I never used Photoshop so unsure if I understand in correct.

bitmap capabilities = 1 bit color formats? pure black or white (not greyscale)?

a “hard” gradient = no clue

 

I'm positive that the effects can be achieved with Photo, but it probably require a totally different workflow.

 

[Hughhh]

45 minutes ago, NotMyFault said:

Could you provide an example document (PNG export) showing the effect? you mention many topics who are probably well known in the Photoshop universe, but I never used Photoshop so unsure if I understand in correct.

bitmap capabilities = 1 bit color formats? pure black or white (not greyscale)?

a “hard” gradient = no clue

 

I'm positive that the effects can be achieved with Photo, but it probably require a totally different workflow.

 

Hi @NotMyFault,

Thanks for your kind and timely answer.

I attached a file depicting the effect.

Brush blend mode is set to “dissolve”, hardness set to 50%. This is what I mean by “hard” gradient in comparison to what the brush usually would produce. 

By bitmap capabilities I meant pure b/w with no greyscale. One can see there is no grayscale involved in the effect, which makes it easy to tint it with color overlays. (I also attached a close up of the same effect with 15% hardness for demonstration purpose)

Also thanks for your effort to decipher my vocabulary, which, I guess, is less program related, but has more to do with my background as illustrator.

Thanks again

 

[josbin]

Here a video:

 

 

[NotMyFault]

Thanks for the video. Really helps to clarify.

To achieve the same effect in Photo:

1. create a rectangle in canvas size in black color
2. add the diffuse filter
3. invert the inherent mask of filter
4. paint in white over inherent mask with soft brush

You can of course create a brush with has the noise pattern baked-in, but aliasing and semi-transparenzy would spoil the effect. Using view/resample mode neigtest neighbor could compensate to some extend.

pure 1 bit pixel layers are unsupported in Affinity and Serif said consistently it has no intention to ever do so. You can achieve the same look with RGB/8 or GREY/8 documents but waist 8 to 24 times storage. Posterize adjustment can help, if you need it on alpha channel use the step function or the quantize function in PT filters.

[josbin]

Hmmm I dont think that it works. Here is the way I understood your instructions. 

 

 

[loukash]

1 hour ago, josbin said:

I dont think that it works

1. disable Wet Edges on your brush (unless it's what you want)
2. use Layer → New Live Filter Effect → Noise → Diffuse

[josbin]

Cool that works. But it is not as intuitive as in Photoshop as the settings of the live filter seems to influence the amount of diffusion and not the Pixel Values itself. Maybe I am not using the right settings. But it is in some ways more powerful than Photoshop as you can create very smooth diffusion. Also i see an edge at the canvas bound. Is there a way to get rid of this?

Thanks and best!

 

[loukash]

The filter depends on the document DPI, and you should always view it at the actual pixel zoom factor or multiplications thereof.
Also, you may want to add the Threshold adjustment to get true 1-bit diffusion.
And as I just noticed, for some reason Threshold only works on brushes that have a solid color background layer below, not on "free floating" brush layers with transparency and nothing underneath. (A bug or by design?) So you may want to add e.g. a white Fill Layer at the bottom of the stack.

Edited January 10, 2024 by loukash
see below

[NotMyFault]

27 minutes ago, loukash said:

And as I just noticed, for some reason Threshold only works on brushes that have a solid color background layer below, not on "free floating" brush layers with transparency and nothing underneath. (A bug or by design?) So you may want to add e.g. a white Fill Layer at the bottom of the stack.

Threshold works on RGB only, not on alpha. Brushes have one color and model opacity over alpha channel.

by using a solid backfill layer, solid color + alpha gets transformed into greyscale color + 100% opacity

 

[josbin]

here is a set up i think is quite nice. Thanks @loukash!

 

 

DiffuseFilterSetup.afphoto

[Hughhh]

Thanks @loukash, @NotMyFault & @josbin for making the effort.
Great to see this solved so quickly, since this has been demanded for quite a while.

I will try to summarize this for everyone in a little instruction:

1. Create a document
2. Select brush tool
3. In the brushes window, select a soft brush (adjust softness to your liking)
4. Double click brush choice to display brush setting dialog window
5. In the dialog window select deactivate wet edges from the wet edges drop down menu
6. In the Layer drop down menu from the top menu bar, select New Live Filter Layer -> Noise -> Diffuse 
7. Adjust desired intensity of diffusion in the Live Filter Dialog window
8. Create a new layer in the layer window and add a solid background with the fill tool (e.g. white)
9. To create 1 bit diffusion (black and white only) add Threshold function from the adjustments selection in the layers panel (third icon in the bottom row, from right) to your Live Filter Layer
10. Enjoy painting with a 1 bit diffused brushed!

I hope I got it right & included everything, let me know if something is wrong or missing.

[rsepierre]

I don't think any of the alternative techniques proposed here does anything close to what the dissolve blend mode does in photoshop.

First, I don't think that a black brush over on a white background is a good test to see if the effect works properly. 
That is because it is not at all specific to brushes and can be used with any kind of layer. But also because it can be used on any color, on gradients, on pictures and a black brush does not test this ability. The dissolve blend mode also doesn't modify the image at all or displace any pixel from it's original position and affects only blending/alpha/transpancy in a non-destructive way.

A better test/exemple would be a colored gradient from side to side combined with an alpha gradient from top to bottom and why not throw a sharp shape in the middle to test the fact that neither the image or the mask's sharpness is modified (unlike with the diffuse affinity filter which adds a "pixellated blur" thus displacing pixels from their original position).

Basically what the disolve blend mode accomplishes is to treat the alpha channel only as either a 0% or 100% value. So a blue layer at 20% opacity over a red layer would result in 80% of the pixels to be completely red, and 20% of the pixels to be completely blue. I assume the distribution is not completely random, but it looks somewhat random.

--> I just discovered while making the test images that indeed the pattern is not random at all. If you superpose a 20% opacity photo on top of a 20% opacity color with disolve blend mode on both, the color layer will be completely invisible as the selected pixels will be the same. If it was random, selected pixels would be different for the photo layer and for the color layer letting some blue pixels coming through.

I joined 3 screenshots testing the effect. I named the layers based on what they do/how they are set up and I hope it paints a good idea of how the blend mode functions.

In my screenshots with the picture layer and color layer (the first one), I added 1% extra opacity to the blue layer (21% total) and we can observe that about 1% of total number of pixels appear blue, 20% are pixels from the picture and 79% are red. Where I did a square cutout in the middle of the picture, we can see that 21% of the total number of pixels appear blue, 79% are red.

My three exemples use a 500x500px canvas resulting in an obvious pixelated effect. It can be less obvious on a 5000x5000px canvas while still providing a unique grain style.

This blend mode is really nice and can be really useful for doing fake pixel art and things or sort.

I'm fairly certain it has been used for the communication of this year's "Nuit blanche" in paris of which you can get a peak of here : https://www.paris.fr/nuit-blanche-2024

 

One way this could be implemented is if the "Dynamic Procedural Texture" was able to fetch data from the channels of the current layer, we could then do something like this : 



The noise() is essentialy acting as a random number generator for each pixels. We could then compare that value to the current Alpha value. If the alpha is 20% then that random value would have 80% chance to be higher. We would then associate a fully transparent or fully opaque Alpha value based on that coin flip. (i'm not sure if it's supposed to be "1:0" or "255:0", but the general logic is here).


Another way it could be achieved is through the half-tone dynamic filter which offers another way of treating values as either completely black or white. Advantage being it's configurability, difference being that it will not appear to be random (this being an advantage or disadvantage is completely up to preference).

But the filter can not be attributed to a layer's Alpha channel and using it on a mask does not seem to work either although it seem's like it should.
--> For exemple the "gaussian blur" filter can be applied to a mask without any issue !!
.

Edited June 14, 2024 by rsepierre
corrections and additions