Tuesday, 3 January 2012

A Gift For New Neighbours

Happy New year! Where did the last half of 2011 go? Ho hum, work has completely swamped my days and nights of late, so the seasonal break was hugely welcome. Along with high spirits and good cheer, I used the spare time to re-introduce myself to ArtRage Pro's brilliant Sticker Spray tool. The subject matter was not initially significant or planned, but grew from brush stroke tests while designing an impasto brush head. It eventually became a fantasy piece in which a mother and baby of unspecified species are welcomed to their new home with a basket of fish. Above them Gannets inevitably begin to gather for scraps. The image is 5000 x 3500 pixels at 300ppi which roughly translates to the imperial paper size, A3.
I've always loved paintings which make beautiful sense when viewed as a whole, but break down to abstract textured marks in close up. The Impressionists and The Glasgow boys are two of my favourite examples of such techniques and I kept them in mind when designing the brush used for this painting.

ArtRage Pro gives us the ability to create editable stickers with depth, gloss and shadow settings. These stickers can be used as single 'peel and stick' elements or sprayed out in user definable ways with the Sticker Spray tool. It is this ability to emit samples in controllable ways which gives us the opportunity to make custom brush heads. The process for this brush involved three stages illustrated in the diagram above (click image to zoom.) Column 1 is the final brush stroke. I made 3 slight variations because sticker spray brushes do not currently react to Artrage's surface and light settings - a heavy impasto, a light impasto and a reversed impasto which digs into the surface. Column 2 is the sticker sheet to which you can add data for colour, texture (depth,) gloss and metallic effects. For this brush I have simply provided colour and depth information. Column 3, the Spray Variation panel is used to fine tune the behaviour of your brush as is the Settings panel in column 4.

The first stage in brush creation is to make the actual brush head bitmap. In this case I made six variations which will be sprayed out randomly to avoid too much repetition in the stroke. Variation must be arranged in a grid on the same page so that each element lies within its own square. Later I will tell Artrage to randomly choose any of these six shapes for each sample sprayed. In order to ensure my brush can use a full colour pallet, the initial brush heads of the colour map must be pure red. This is simply because ArtRage uses pure red as the starting point in its colour processing. The colour map actually has a transparent background and is loaded as a png file. Transparency discards everything but the actual brush shape. The next map along, the depth map, is black and white where black represents no depth and white is maximum depth. This map is used to add depth to the heavy impasto brush. The depth map for a lighter impasto effect changes the white to a dark grey. The reversed brush uses a white background with black shapes.

The colour and depth maps are next loaded into a newly created sticker sheet within ArtRage (see column 2.) I could have created my sticker sheet as a single row of six shapes, it doesn't matter as long as type in the matching numbers bottom right of the sticker sheet; columns: 3, Rows: 2. Artrage now draws the correct grid showing the six shapes contained in their own squares. I also choose where to store the new sticker sheet and give it a name then press OK. Column 3 of the diagram shows the Spray Variation panel accessed through Settings. This is where I give the brush its characteristics. I want the brush to access the full colour pallet so I set Hue/Tracing H to 100%, Luminance/Tracing L to 50% and Saturation/Tracing S to 100%. Next I want the brush lay down any of the 6 available shapes in random sequence so I set both Sheet Row and Sheet Column to 100% Random. I make the brush pressure sensitive in two ways. First by increasing brush size with pressure via Scale/Pen Pressure and second by increasing the transparency of the mark via Alpha/Pen Pressure. I also set Rotation/Stroke direction to 100% to make the brush shapes follow the directions of stroke. Finally I set Luminance/Base value to a low negative value to compensate for the effect the depth lighting has on colour (er, I think!) EDIT: Wait, that last sentence is wrong. :D It turns out my colour map wasn't quite pure red (originally done in Photoshop.) To fix this I imported the map into ArtRage, coloured it up then re-exported and now no compensation is necessary. Finally I return to the Settings panel, set the Spray Rate to 95% and make sure the Auto-Flatten and Continuous settings are checked. If Auto-Flatten was not checked hundreds of thousands of samples would be editable which would eat your computer memory in no time. Continuous emits samples even when your hand has stopped moving. It is like Photoshop's Spray Gun setting.

I've realised it is easier to make a new brush than to describe making a new brush. :) Click on images to enlarge.