Corel Painter "weird artifacts" on canvas
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  1. #1
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    Corel Painter "weird artifacts" on canvas

    Hello everyone,

    I'm having some problems with my Corel Painter and I was hoping someone could give me some advice on how to fix it.

    The thing is, I'm having these strange markings every time I paint. No matter what brush I use, these artifacts which seem like diagonal lines and burn marks start to appear as I paint. And this is most notable when I paint on a new layer. I'm using Corel 11, but the same thing used to happen when I used 10. It's really ugly and it messes up my work.

    I don't know how to exactly explain the situation as I think it's uncommon. But I hope anyone with greater experience in Corel can understand what I mean with the image I've attached.

    If there's any other info that I've left out, please let me know.

    Thanks.

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    Does the diagonal lines bug happen in Painter 11? Did you installed the last update in Painter 10? I thought this bug was fixed!

    About the second issue, it is a well know bug. I observed it at least from Painter 6 (it was even worst) to Painter 12. And there is not any real fix, just a workaround if you know what is happening.

    So here an explanation:

    1-I have made a simple test based on opaque to transparent samples (see the RIF file in attachment). Each sample is using the same background color so all of them are invisible if you don't hide the background. Here is what they look like.

    The numbers indicate the amount of opacity per sample.

    2-The goal of this test is to show exactly what is happening.
    I used this kind of brush so the bug will appear quickly


    3-Now you just need to paint using more or less brush pressure. The bug is appearing when using low opacity brush strokes. You can use the background color or a brighter color if you want. You need to paint on samples layer only.

    4-That is the kind of result you will obtain

    With any other program you will get something like this

    so, nothing special is visible

    5-Now, you can observe on Painter result (version 11 here) that the brush behavior depends on how opaque or transparent is a layer.
    On 100% opaque area, the gradient is just smooth but under 100% opacity, Painter produces a weird ugly result. That's because of a bug which changes a little bit the color of a dab depending of the pixel opacity you are covering:
    If the pixel is opaque -> no bug
    If the pixel is non opaque -> there is a color shift which changes considering the amount of the pixel transparency

    Now, as a brush stroke is the combination of multiple basic shapes like you can see there

    The bug is fed by itself till the area of a layer reach 100% opacity. That's the "oily" rendering you get in your post.

    This bug happens with all highlighted dab types so that's a very important bug in my opinion.


    Painter 12 introduced "stroke attributes" setting and I think using it fix this bug at the price of performance loss anyway. I am not 100% sure since I tried only the trial quickly.


    As I said, there is no fix for your Painter version. You can increase opacity of your brush, or avoid painting on transparent area or such workaround...

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    Hello Hecartha,

    Finally a response! First of all, wow, thank you for such a detailed explanation. I really appreciate the effort and time you took to just help a complete stranger. Seriously, I wasn't expecting such grand gesture.

    So it IS a common problem afterall... I was beggining to think it was happening only to me, as I've never heard anyone else complain about this. Yes, these ugly markings happened with 10, and now the same thing is happening with 11. And yes, my 11 has its updates.

    But being that these are really bugs from the software, I guess there's nothing I can do, except follow your instructions, cause you're absolutely right about what's going on here. Now that I've read your explanation, I think you pretty much nailed it. Yes, painting on a new layer does originate those markings, while painting directly on the canvas doesn't.

    So does this mean that the only solution to avoid these markings is the fact that my brushes will have to be set at 100% now, with little or no pressure sensitivity? Man, that would really be a drag and remove the thrill of brush customization that the software provides... Which is actually why I paint with as little layers as possible. Mostly I'll flatten everything down and work on the canvas (cause again, painting on the canvas layer is fine). But this however, and obviosly, can become very limiting for when wanting to edit colors, etc, or even fix eventual mistakes on the artwork.

    Anyway, I'll look into it and again thanks for the help. Atleast now I know what I'm facing up against and its no mystery anymore.

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