PDA

View Full Version : Color Artifacts with Digital Watercolor


Thoughtcast
12-12-2005, 03:56 PM
Hi.


Recently I have been doodling in Painter IX, and have discovered a rather irritating problem.

It seems that the Digital Watercolor brushes tend to burn themselves when applying a specific amount of pressure with the pen. I'm using a Wacom Graphire 3 at school, and an Intuous 3 at home, however, this problem occurs using both, so I strongly doubt that it's hardware-related.

The problem results in strange color artifacts, where the colors suddenly go green, blue, or sometimes red, independent of what color i'm actually painting with. The otherwise painterly edges of my strokes become razor sharp, and this can only be remedied by applying more pressure (overriding the artifact with a darker color), or drying (at which point I need to draw over with an opaque brush to get rid of the jagged edges).

It really bothers me since I loose some flexibility with getting down different values fast (which is what I mainly use the Digital Watercolor for). Maybe I could be using some other brush category, but I can't quite stand the thought of having strange problems occuring whenever I feel like using DW.

I'll throw up some screenshots.

http://webis.sofe.se/lijg04/color_artifact_CPIX_001.jpg

http://webis.sofe.se/lijg04/color_artifact_CPIX_002.jpg

http://webis.sofe.se/lijg04/color_artifact_CPIX_003.jpg


Now, the way I see it; using a slightly orange color on a blue background might produce som green colors when painting with DW, because of how they work (in sort of a multiply-mode), but using a neutral blue color on a blue background probably wouldn't, and using an orange color on orange background ceartainly wouldn't.

I read about and tried manipulating the Bleed and Resaturation values, but they really didn't make a difference when it came to the artifacts. I also thought I might have accidentally applied some Color Variability to my brush, but after having checked, I could see that all three sliders were at 0.

Maybe it could have something to do with the color and gamma settings of my graphics card, but I recently calibrated my monitor using Quickgamma, so I'm fairly sure I get a good representation of colors.

If anyone has any idea or has experienced similar problems, please speak your mind.

skwearsercle
12-14-2005, 05:22 AM
I have not been able to dulicate the problem. If you give me all the specific settings of the brush you are using and any other relevent info I will try again.

Thoughtcast
12-14-2005, 10:44 AM
Alright.


The brush I'm using where the problem is most pronounced has the following settings: (It's a slightly modified Broad Water Brush)

General:

Dab type: Circular
Stroke Type: Single
Method: Digital Wet
Subcategory: Grainy Digital Wet Abrasive

Opacity, bound to pressure
Grain, 8%, not bound.


Spacing:

Spacing: 10%
Min Spacing: 0,7
Damping: 20%

Continuous Time Deposition, unchecked.
Cubic Interpolation points: 0.


Size:

Min Size: 73%, not bound.
Size Step: 5%


Angle:

Squeeze: 85%
Angle: 0, not bound.
Ang Range: 0.
Ang Step: 0.


Well:

Resaturation: 10%, not bound.
Bleed: 70%, bound to pressure inverted.
Dryout: Max. (That is to say, the slider is at max, so the brush should never dry).
Brush Loading, unchecked.


Random:

Jitter: 0,18, not bound.
Random Brush Stroke Grain, unchecked.


Impasto:

Draw to: Color.


Digital Watercolor:

Diffusion: 0
Wet Fringe: 2%


Color Variability:

HSV, all sliders at 0.


Color Expression:

Controller: None.


That should be it for the brush settings. Some other relevant information might have been what type of screen I use, what type of graphics card I use and so forth, but I have tried the brush on several other computers now, and the problem persists.

It's probably due to me having fiddled with the brush settings while not understanding them correctly, but it would be really nice if I could understand exactly what is causing the artifacts, so as to avoid them in the future.

Simply changing the Stroke Type on the Broad Water Brush from Rake to Single makes the artifacts appear. You might say that is actually the cause of the problem, but since there are a number of DW-Brushes that have their Stroke Type set to Single and not having such a pronounced artifact problem, that could hardly be the end of it.

skwearsercle
12-14-2005, 09:57 PM
I'll have a closer look at this over the next few days. However in the meantime it does look like another instance of a badly buggy tool not working properly. I can reproduce the effect with the off the shelf bog standard Broad Water Brush

I don't think the sharp edge is much of a problem as that is probably part of the watercolour effect. However the brushes do seem to put down a variation of dab colours.

I agree that it does look a lot like some slight colour variability has been dialled in, (it hasn't).

I'll try and pin it down over the next few days. But I am reasonably sure that it is just a broken tool as usual and nothing to do with your hardware.

As a side note I find that the standard broadwater with the rake stroke type also produces the colour changes like the single stroke.

Thoughtcast
12-16-2005, 11:38 AM
I agree that the sharp edges really doesn't present much of a problem most of the time, they're part of the reason I use DW, but sometimes they get overly accented, like when the color artifacts appear. The edges get too sharp.

I myself haven't been able to get the color artifacts to appear using the standard Broad Water Brush, but then again, I haven't tried it that much.

I'm glad someone who's probably got a better knowledge of Painter than I is looking into the problem. Hope there is an easy enough workaround, or at least, explaination.

Archibob
12-20-2005, 11:42 PM
i have often had the same problem, but i thought it was just my calibration or something. next time it occurs, i'll take some screenshots too. i'm glad it's not just me


=BoB=

zerae
12-24-2005, 10:53 PM
Yes it happens all the time, very easy to reproduce I can take a bunch of screenshots if you want. My workaround is to apply the watercolors in a single passage if I work them too much it happens that. Paper texture is also important and seems to affect how the watercolors behave.

ivanushka
12-28-2005, 09:11 AM
I have very similar problems, when using the 'airbrush detail brush' tool. The artifacts seem most aparent when their is a hard transition in color hue, and the same artifacts are almost non-existent when there is a soft color transition..

CGTalk Moderation
12-28-2005, 09:11 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.