Blend Mode: Darker Color not painting over white canvas (please, test with graphic tablets)

[Jose3DSigner]

I want to create a pencil brush for sketching but I discovered that it is not possible in AP because, as you can see in the picture, the strokes accumulate tint at their superimposed parts, where the lines intersect.

A properly usable pencil should have a maximum limit of pigment/tint or, at least, a way to allow color replacement only if the stroke is darker, depending on pen pressure.

A logical solution could be setting Blend Mode = "Darker Color" but the brush engine doesn't paint strokes over white, I don't understand why. Not even "subtract", "difference" or "exclusion" modes work as expected, using black color brush over white canvas.

[Callum]

Hi Jose3DSigner,

This is by design its not really a bug I'm afraid. As far as I'm aware this will always be the case when working with grey scale textures etc. You can see a member of our QA team giving more information regarding this here: 

 

Thanks
C

[Lisbon]

Hi @Jose3DSigner

I probably won't be able to help you but I would like to understand better the problem.

Looking at your example, it looks like a regular brush with low opacity, am I right?
Or is it a texture like the example provided by @Callum?

[Jose3DSigner]

Yes, it's a brush with 100% opacity at maximum pen pressure so, under 100% most of the time.

Then, it does not have texture, some rotation and flow jitter though.

BTW, the darkening occurs with and without texture because the problem seems to be the "Blend Mode", I think.

 

[Jose3DSigner]

In order to avoid the darkening, I think the most appropiate blending mode should be "darker color" but it doesn't work as I expected because the brush paints lighter color pixels as well.

Thank you @Lisbon

[Old Bruce]

21 hours ago, Jose3DSigner said:

the strokes accumulate tint at their superimposed parts, where the lines intersect.

Isn't that the way it works in the real world with real pencil on real paper? More graphite/pigment added means the line will get darker.

Remove all the Dynamics and set up like this to start. For light grey I chose light grey in the colour panel. For darker colours use darker colours.

 

[Lisbon]

Ok Jose.

Like @Callum said this is by design and i believe the problem is related to the fact that you are not using 100% opacity. And when I speak of opacity I am including flow and accumulation. And if one of them isn't 100% you're going to have that accumulation problem when the brush lines cross.

So whatever you do you should have opacity/flow/accumulation set to 100% and then set the right color.

Here is an example:

As you can see, in the image on the right there is no accumulation where the lines intersect.

Hope this helps.

[Jose3DSigner]

Well, from the example, I deduce you are probably using a mouse, not a graphic tablet.

Depending on pen pressure, alpha/transparency may vary from minimum 0% to maximum 100% so, we have a problem with opacity, right? I mean, if you repeat your example with a graphic tablet, the second cross will have the same darkening problem.

Thanks @Lisbon.

 

 

 

[Jose3DSigner]

1 hour ago, Old Bruce said:

Isn't that the way it works in the real world with real pencil on real paper? More graphite/pigment added means the line will get darker.

 

1. Pencils may have different softness, for instance 4B, HB or 4H, meaning they have a maximum value or opacity, 4B is the darkest but never reaches black.

2. It works with a mouse, not with a graphic tablet since the pen pressure affects the opacity.

[Old Bruce]

13 minutes ago, Jose3DSigner said:

Well, from the example, I deduce you are probably using a mouse, not a graphic tablet.

Cant speak for Jose3DSigner but I used a Wacom pen and tablet. I had to turn off everything in the dynamics section to get it to work like you want. Less pressure More pressure same colour strokes on top of or beside other strokes.

6 minutes ago, Jose3DSigner said:

2. It works with a mouse, not with a graphic tablet since the pen pressure affects the opacity.

Turn off the Dynamics.

[Jose3DSigner]

@Old Bruce

Why should I turn off the dynamics. Pencils respond to pressure, they're not felt pens.

What I need is a BLEND MODE that works properly, that's the bug I'm referring to.

[Lisbon]

40 minutes ago, Jose3DSigner said:

Well, from the example, I deduce you are probably using a mouse, not a graphic tablet.

You're right.

41 minutes ago, Jose3DSigner said:

Depending on pen pressure, alpha/transparency may vary from minimum 0% to maximum 100% so, we have a problem with opacity, right?

Exactly. It's hard for me to explain, but if the opacity isn't 100%, it tries to build up the strokes and as result you see that accumulation.

43 minutes ago, Jose3DSigner said:

I mean, if you repeat your example with a graphic tablet, the second cross will have the same darkening problem.

You mentioned the word tablet so many times, but somehow i didn't pay enough attention.
Sorry for that Jose.

45 minutes ago, Jose3DSigner said:

Thanks @Lisbon.

I didn't help much, but You're welcome.

[Jose3DSigner]

@Lisbon

Very much appreciated, thanks!

[Old Bruce]

42 minutes ago, Jose3DSigner said:

@Old Bruce

Why should I turn off the dynamics. Pencils respond to pressure, they're not felt pens.

What I need is a BLEND MODE that works properly, that's the bug I'm referring to.

I am assuming you want the grey colour to be the same on all strokes regardless of whether or no they are overlapping.

Try Luminosity for blend. 

[Jose3DSigner]

I already tried it and, furthermore, I tried all the blend modes without success. I think blending is not working properly or the brush engine concept is not correct.

Thanks for your attempt to help @Old Bruce

[Old Bruce]

If the brush has any transparency then the strokes will get darker when you do a second pass. The transparency can be in the brush itself or set with the flow, hardness and accumulation settings with or without dynamics involved.

I think what you are needing is a brush which will change the colour or tint as pressure is varied. To the best of my knowledge Affinity has no such brushes.

[Jose3DSigner]

Yes, it can be understood as a tint replacement depending on the pressure, instead of tint accumulation,
but there is an important exception to that: lighter pixels should not replace darker pixels,
that's why I referred to "Darker Color" blend mode previously, as a possible bug.

All the best.