Pixelation

General => General Discussion => Topic started by: Lethandralis on October 06, 2017, 03:33:30 am

Title: Saturation Shifting
Post by: Lethandralis on October 06, 2017, 03:33:30 am
I have a good understanding in hue shifting in pixel art now. I have still have two questions regarding shading though:

- Does saturation always go up as the shades get darker? Is the saturation shift always necessary, should it be subtle or really noticable?

- How does environment lighting affect hue shifting? I normally hue shift from purple(darkest) to yellow(brightest), but does this only applied to environments lit by sunlight? What if my sprite is illuminated with a blue or purple light?
Title: Re: Saturation Shifting
Post by: eishiya on October 06, 2017, 04:18:36 am
Saturation goes up or down depending on the look you want, the material you're colouring, and the light. For example, skin and wax will often have more saturated shadows because of their slight translucency, which allows light to bounce around inside of them, picking up more of the hues, whereas more opaque materials like painted wood will have duller shadows. Strong direct light that penetrates objects will often drag more colour/saturation into the shadows than weak or diffuse light which bounces off the surfaces.

In addition, the similarity of the lights (key, ambient, etc) to the colour of the object affects the saturation. If they match, the object's colour will be reinforced, leading to higher saturation. So, if you have a green object in a green environment (=green ambient light), it'll have more saturated shadows than it would in a red or grey environment, where the ambient light does not reinforce its colour. The same goes for any other light sources - a green object lit by a red lamp will have less saturated highlights than it would when lit by an otherwise identical green lamp.


The light in the environment determines the directions in which you shift. Sunlight and incandescent lightbulbs tend to colour things yellow-ish, which is why we often hue-shift highlights towards yellow. The blue sky often acts to create a blue ambient light, which is why shadows are often depicted as bluish, and many artists tweak that to purple simply because that looks better contrasted against yellow, being its complement. Artists often use this "yellow lights, purple/blue shadows" set-up because it's something that most viewers are used to and it fits many of the common environments seen in artwork - but you're right, it's mainly meant for outdoor environments lit by sunlight. If your environment has different light sources, then those should probably affect your choice of hue-shifting. If you have a red-coloured environment with blue lamps, then the key light will be blue and you'll want to hue-shift your lights towards blue, and the ambient light will be red so you'll want to make your shadows redder. If you have a red environment with red lighting, then all the hues will be shifted towards red.


If you're interested in learning more about light and how it affects the colours of objects and their shadows, this is an excellent tutorial (http://www.itchy-animation.co.uk/light.htm). The tutorial consists of four sections, so don't miss the links at the end of each section.
Title: Re: Saturation Shifting
Post by: Lethandralis on October 06, 2017, 05:47:48 am
Thank you for the detailed answer, it is really helpful. The tutorial looks really useful, I'll study it as soon as I get the time.