Digital painting and intuitive color blending in the HSL space
May 13, 2015 9:18 PM Subscribe
I've been fooling around with Procreate a little bit recently, and it's great! But I find "blending" between two colors with the HSL-space color picker pretty difficult. Is there a smarter way of doing this that I'm missing?
Here's a color test that I did. The top one was pretty easy to achieve -- I found that, for a given hue, the next darkest hue that was actually perceptually the same rather than numerically the same was easy to find by stepping roughly the same distance in both the Saturation and Lightness dimensions. The bottom one, a blend between two colors (the top row is just the result of smudging the bottom one and erasing in between), looks okay to me, but I couldn't do it just using the color picker -- I had to basically just mix the colors on the canvas by using a wet brush and letting the paint run out until I had a solid blended middle value, then use the color dropper and repaint the area using that. That process works, but it's pretty slow and requires that I switch between brushes if I'm not already using a wet paintbrush on whatever it is I'm actually drawing. Is there anything similar to my diagonal trick that works for interpolating between colors when you're using a standard HSL color picker? Just leaving the Saturation and Lightness values in place while adjusting the Hue didn't yield anything close to a believable blend for me, so it seems like it's more complicated than that. Or is it just a limitation of that particular color space that I'll have to work around?
Here's a color test that I did. The top one was pretty easy to achieve -- I found that, for a given hue, the next darkest hue that was actually perceptually the same rather than numerically the same was easy to find by stepping roughly the same distance in both the Saturation and Lightness dimensions. The bottom one, a blend between two colors (the top row is just the result of smudging the bottom one and erasing in between), looks okay to me, but I couldn't do it just using the color picker -- I had to basically just mix the colors on the canvas by using a wet brush and letting the paint run out until I had a solid blended middle value, then use the color dropper and repaint the area using that. That process works, but it's pretty slow and requires that I switch between brushes if I'm not already using a wet paintbrush on whatever it is I'm actually drawing. Is there anything similar to my diagonal trick that works for interpolating between colors when you're using a standard HSL color picker? Just leaving the Saturation and Lightness values in place while adjusting the Hue didn't yield anything close to a believable blend for me, so it seems like it's more complicated than that. Or is it just a limitation of that particular color space that I'll have to work around?
Best answer: But I find "blending" between two colors with the HSL-space color picker pretty difficult. Is there a smarter way of doing this that I'm missing?
You're right, it is extremely difficult. There are major issues with the HSL "hue ring" color picker system, and in Photoshop at least there are alternative color pickers like Coolorus and MagicPicker that can help you get around it.
The Linux programs Krita and MyPaint 1.1 use a proper painter's wheel in true HSL space (and not HSB). It looks like Layers for iPad has a hue wheel with a Brightness slider, which is a good compromise.
Here's the problem: a proper painter's wheel has the most saturated colors as a ring on the circumference of the circle, gradually getting less intense until all the colors become neutral (white or gray) in the center. Here's an example, on the right.
Given any two colors as points somewhere within the circle, a line can be plotted in the space that describes all the colors that exist as mixtures between the two. If the two colors are very far apart (like complementary colors, totally opposite each other on the wheel), the line will pass through many neutrals on the way.
Given three or more colors on the circle, you can plot a polygonal gamut representing all the coordinates of all the colors that could be mixed from those colors. The relatedness of these colors within the bounds of that polygon is what gives limited palette paintings their harmony. Here's an example from James Gurney's book on the subject, Color & Light.
In most digital painting programs (including Procreate), you don't have a proper painter's wheel. Instead, you have a hue ring with a shade selector inside. This setup makes it practically impossible to navigate along the line plotted between two given colors on the painter's wheel, because you can't intuitively shift both hue and saturation simultaneously. If you're a very skilled and experienced digital painter, you know how to work within these constraints, but it's a flawed system that deserves to be fixed.
posted by overeducated_alligator at 9:31 AM on May 14, 2015 [1 favorite]
You're right, it is extremely difficult. There are major issues with the HSL "hue ring" color picker system, and in Photoshop at least there are alternative color pickers like Coolorus and MagicPicker that can help you get around it.
The Linux programs Krita and MyPaint 1.1 use a proper painter's wheel in true HSL space (and not HSB). It looks like Layers for iPad has a hue wheel with a Brightness slider, which is a good compromise.
Here's the problem: a proper painter's wheel has the most saturated colors as a ring on the circumference of the circle, gradually getting less intense until all the colors become neutral (white or gray) in the center. Here's an example, on the right.
Given any two colors as points somewhere within the circle, a line can be plotted in the space that describes all the colors that exist as mixtures between the two. If the two colors are very far apart (like complementary colors, totally opposite each other on the wheel), the line will pass through many neutrals on the way.
Given three or more colors on the circle, you can plot a polygonal gamut representing all the coordinates of all the colors that could be mixed from those colors. The relatedness of these colors within the bounds of that polygon is what gives limited palette paintings their harmony. Here's an example from James Gurney's book on the subject, Color & Light.
In most digital painting programs (including Procreate), you don't have a proper painter's wheel. Instead, you have a hue ring with a shade selector inside. This setup makes it practically impossible to navigate along the line plotted between two given colors on the painter's wheel, because you can't intuitively shift both hue and saturation simultaneously. If you're a very skilled and experienced digital painter, you know how to work within these constraints, but it's a flawed system that deserves to be fixed.
posted by overeducated_alligator at 9:31 AM on May 14, 2015 [1 favorite]
Response by poster: Cool, thank you Chicoreus for the bevy of informational links and overeducated_alligator for the extended discussion on the difficulties and alternatives. It seems like blending on the canvas really is the best option, which isn't so bad, and I guess doing it on a different layer negates the risk that I'll mess something up by blending over it.
posted by invitapriore at 3:14 PM on May 14, 2015
posted by invitapriore at 3:14 PM on May 14, 2015
This thread is closed to new comments.
Here's a few tips for what I do when making color scales, blending, etc. This should apply to any digital painting program.
I've linked other people's videos of the actual process below, since it's easier to show it visually.
When do I use the color wheel?
1. Only at the very beginning, I start by picking the two end colors off the color wheel (purple and blue in your case), after this all the color mixing will be done on screen (meaning I won't have to fiddle with the color picker anymore : ) )
What tools do I use?
1. I switch to a soft round brush set at 50% opacity or so to do the actual blending between the two colors (I usually paint with only three basic brushes, so I probably have this one up already).
2. I use the ALT key to switch between the eyedropper tool and my brush when needed (this is really handy since you'll need to switch a lot and pick colors off the screen when painting)
3. I almost never use the smudge tool to do this, I've linked a video explaining why below (I literally can't remember the last time I used smudge for something).
Videos:
CtrlPaint: Brush Blending Technique Explains the basic blending process, this is in black and white, but it applies to color as well.
Demo of making a value gradient A shorter video of someone blending between four gray values.
CtrlPaint: Blending Practice Some practice blending exercises, with a linked practice sheet to work on.
CtrlPaint: The Smudge Tool Why I don't use the smudge tool to blend colors/what the smudge tool is actually useful for.
About color pickers:
Sycra: How to Choose Colors and Use a Painter's Wheel Longer intro to using the color picker and basic color theory. Great video, pay attention to when he talks about perceived color versus actual color (3 minutes, 10 seconds: When he's talking about the "red" colored goblin's ear.)
CtrlPaint: Color Pickers Shorter intro to the basic color picker.
CtrlPaint: Alternative Color Control Other color pickers that you might have in your program and what they do, this video is Photoshop specific I think.
posted by Chicoreus at 7:41 AM on May 14, 2015 [1 favorite]