Understanding Sticker Spray colour

[Juz]

This tutorial will outline how to use colour with the sticker spray tool. In order to get the most of out this tutorial you should have a basic knowledge of how to create stickers and how to make use of them as stickersprays.

You can learn basic sticker creation with Someonesane's video demonstration here:
http://www.youtube.com/watch?v=0iSJNHe4dT4
or with Judith Tramayne's video demonstration here:
http://www2.ambientdesign.com/forums...ad.php?t=24794

And you will find some good information on stickersprays in my Using Photoshop Brushes in AR3 tutorial here:
http://www2.ambientdesign.com/forums...ad.php?t=26478


There are two areas where we can define colour with sticker spray brushes. Firstly, within the sticker image itself and secondly using the Spray Variation Dialog.

Understanding Sticker Spray Colour.

Attached is an image of the Computer Colour Spectrum. We can see underneath the Red, Green and Blue primary colours (RGB) that when added together in varying ways will allow us to mix any colour within this spectrum.

If we look at the vertical dotted lines in this diagram we can see that Red (255,0,0) is the starting and ending colour value 0°/360°. Green our second primary colour of RGB sits at 120°. Our last RGB primary value of Blue is at 240°. We can also see that mixing Red with Green and no Blue will result in Yellow(60°). Green with Blue and no red will result in Cyan (180°). Red with Blue and no Green will give us magenta (300°).

[Juz]

As Artrage users we are familiar with this colour spectrum as we use it to select our hues of colour (see attached).

The important thing to notice is that in all of these different displays of the spectrum the value Red (255,0,0) is ALWAYS the starting and ending value (0°/360°). This value of Red is our Reference Value/Base Value for how Artrage will calculate a sticker colour.

It is helpful to think of this value of red (255,0,0) as the default/home colour for your sticker hues.

[Juz]

When working with colours as degrees of hue, it's much easier for us to have the spectrum laid out in a circle (full 360°) rather than a linear fashion. This will make a better roadmap for us and it will be easier to predict how hues will move as we design brushes .

There are two ways this can be done. If we start at Red we could move in one direction through yellow then green. We could also proceed in the opposite direction through Magenta then Blue.

It does not matter which way the colours are laid out as the program code will start at 0° Red (255,0,0) and increment degrees of hue in a positive or negative direction starting from this 0° Red value.

[Juz]

Here is an example from Artrage and Painter side by side. Moving clockwise from our Base Red Value, Artrage travels through Magenta then Blue whereas Painter travels through Yellow then Green.

[Juz]

I've laid out the colours in the same direction as the Artrage hue wheel. This wheel will aid in predicting how our sticker spray colour will behave (download a copy for a roadmap).

I've also made these values into a brushmaking.col for you to use for your own original sticker creation (download from under the colour wheel).

Be sure to only use this palette for brush making or monitor output work. These values are right out of the CMYK gamut and will result in very disappointing prints. I will not be offering it up in the art supplies section for this reason.

[Juz]

Before we get into the 'meat and potatoes' of creating and using colour in sticker spray we need to be aware of some options in our Spray Variation panel. This panel uses the HSL (hue, saturation, luminance) colour space for colour.

Whenever we use either 'Setup Settings for an Object Spray' or 'Setup Settings for an Image Brush' from the menu dropdown our default property values for colour are the same.
The 'Hue' property has a value of 'Tracing H' @100%, the 'Luminance' property has a value of 'Tracing L' @50%, the 'Saturation' property has a value of 'Tracing S' @100% and the Alpha property has a value of 'Tracing Alpha' @100%.
This means that the program will trace the HSL (hue, saturation and luminance) values as well as the alpha (opacity) values of any colour we choose with our usual colour selection methods all relative to our base red (255,0,0) 0° 'home' colour.

[Juz]

Here is a visualisation of HSL colour space.

You can see from this diagram that hues wrap around the circumference, saturation proceeds from the outer toward the core with values least saturated at the core and luminance runs from the top lightest values to the bottom darkest values. Our colour wheel road map is a slice from the exact vertical centre, 50% from the top lightest value and from the bottom darkest value. This is why our default setting in the Spray Variation panel for luminance starts at 50%.

[Juz]

How the Hue of our original sticker affects the Traced Hue of our brushstroke.

When we create our sticker for a sticker spray in our (255,0,0) red, the traced colour will be the exact HSL value we choose. So if my sticker is made with the 'home' colour and I choose blue to paint with the resulting brushstroke will be blue.

[Juz]

Lets look at what happens if we make our original sticker Magenta.

On our colour wheel, the hue of Magenta is located at +60° from our 'home' colour of red. When I choose the same blue to paint with the resulting colour will be +60° from that blue giving us cyan.

[Juz]

In the same way we can predict values that move in a negative direction from our 'home' colour of red. Lets look at yellow.

On our colour wheel the hue of Yellow is located at -60° from our 'home' colour of red. When I choose the same blue to paint with the resulting colour will be -60° from that blue giving us Magenta.

Any degree of hue we increment from our 'home' red in a sticker will be reflected as the same degree of hue increment in our 'traced' (chosen) colour. If I travel 90° of hue in a positive direction the traced hue will follow suit i.e. the brushstroke will be 90° (travelling around the spectrum in a positive direction) from the colour I select for my brushstroke.