First of all, I just want to say how kick ass I find this program to be. Now that has been said, let's move on:

I am a developing concept artist (http://en.wikipedia.org/wiki/Concept_art) and I use the computer with a tablet as a painting tool.

To get onto the issue:

Currently, the blending is very flat, and does not work to paint with. The behavior is that of default Photoshop with opacity mapped to the pen pressure.

In Photoshop I have managed to get a smoother blending by combining Opacity and Flow. Set opacity to 100%, and set it to pen pressure. Set Flow to 10% (in the top menubar, not the jitter in brushes palette), and to pen pressure. That gives a more mixed, uneven and gradual build-up.

In gimp I now noticed that the airbrush has more or less the same effect as Flow. The airbrush used alone gives a very fuzzy color...But if you could *combine* the airbrush and the more solid color with opacity, you would get something in the middle, "the best of both worlds" :-)

So if you could combine those two, like add an airbrush slider under the opacity slider, it would rock.

What do you think?

If anyone would want to work on this I would be more than happy to give a donation for the cause. I am going to donate some anyway, so it would be fun to give the donation for this specific task. Some 80 USD is what I can spare at the moment, and more for any other features I find would get more painters/illustrators to use the gimp.

www.conceptart.org/forums is *the* community for concept artists and also illustrators. Here is a thread with a discussion about Gimp and Linux: http://www.conceptart.org/forums/showthread.php?p=1076843#post1076843

Although they don't specifically discuss the blending in gimp, you now know there is an interest in this field of craftsmanship to use the gimp beyond the person writing this email :-)

Thanks -Nils

On 11/16/06, Adrian Likins wrote:

Nils Nordén wrote:

Currently, the blending is very flat, and does not work to paint with. The behavior is that of default Photoshop with opacity mapped to the pen pressure.

In Photoshop I have managed to get a smoother blending by combining Opacity and Flow. Set opacity to 100%, and set it to pen pressure. Set Flow to 10% (in the top menubar, not the jitter in brushes palette), and to pen pressure. That gives a more mixed, uneven and gradual build-up.

In gimp I now noticed that the airbrush has more or less the same effect as Flow. The airbrush used alone gives a very fuzzy color...But if you could *combine* the airbrush and the more solid color with opacity, you would get something in the middle, "the best of both worlds" :-)

So if you could combine those two, like add an airbrush slider under the opacity slider, it would rock.

What do you think?

Sounds like a reasonable idea to me. If I understand correctly, the gimp parallel would be to allow pressure to map to brush spacing?

Was thinking about the same thing recently, after hooking up my tablet for the first time in a while.

Adrian

I looked up some stuff to really understand what flow does, and according to http://www.mambo.net/as/view/159 it seems to be time-based on how rapidly the paint will "flow" out of the cursor. Now, what I discovered is that the Airbrush tool in Gimp actually has something like this, it's called "Rate".

From the manual: "The Rate slider adjusts the speed of color

application that the airbrush paints. A higher setting will produce darker brush strokes in a shorter amount of time."

So this feature is already implemented....now all it needs is some tweaking.

Here I have illustrated some tests with the advantage of flow in photoshop, and compared it to the behavior of the gimp airbrush. At the bottom you can also see the difference in behavior between the gimp airbrush rate, and photoshop flow.

http://www.turtleart.net/stuff/flow.jpg

On 11/17/06, David Gowers wrote:

On 11/17/06, Nils Nordén wrote:

So this feature is already implemented....now all it needs is some

tweaking.

Here I have illustrated some tests with the advantage of flow in photoshop, and compared it to the behavior of the gimp airbrush. At the bottom you can also see the difference in behavior between the gimp airbrush rate, and photoshop flow.

http://www.turtleart.net/stuff/flow.jpg

Your image is unfortunately likely to be misleading. I have the strong suspicion that Photoshop is set up to also modulate opacity according to tablet pressure (unless you've done that image with a mouse, which seems unlikely.)
I suggest you check any opacity-related settings and remake the image.

The Photoshop settings I used for opacity were 100%, and Brushes Palette > Other Dynamics > Opacity control: pen pressure

Gimp settings were Opacity: 100,0 and Pressure sensitivity: Opacity [check]

So, there should be no differences there between the opacity settings in both apps.

What is it you find fishy? I used a wacom tablet btw.

On 11/17/06, Sven Neumann wrote:

Hi,

On Fri, 2006-11-17 at 12:26 +0100, Nils Nordén wrote:

I looked up some stuff to really understand what flow does, and according to http://www.mambo.net/as/view/159 it seems to be time-based on how rapidly the paint will "flow" out of the cursor. Now, what I discovered is that the Airbrush tool in Gimp actually has something like this, it's called "Rate".

From the manual: "The Rate slider adjusts the speed of color

application that the airbrush paints. A higher setting will produce darker brush strokes in a shorter amount of time."

So this feature is already implemented....now all it needs is some tweaking.

I very much doubt that any of the active developers have the time and motivation to do such tweaking. So perhaps you should give it a try yourself. If you need help with the source code, feel free to ask.

Sven

Ok! I think lowering the effects of "Rate" could be the solution...so that shouldn't be too hard for me to test on my own. Now I know what to dig into.. good. This is gonna be fun. I'm sure I'll need some help later on. Thanks!

Nils