Here is a project for the studio where I work in-house. The drawing was executed in Inkscape based on a sketch scan, and seamlessly exported in PDF. Setting the option, I was able to preserve the alpha transparency, which was correctly interpreted and rendered by Acrobat.
Exactly what is Alpha transparency and why is it so important?
Most Artwork and desktop publishing applications deal with vector graphics.
Vector graphics are flat regular or irregular polygons described by Bezier curves, a special type of parametric curve introduced in automobile design in 1962 by French engineer Pierre Bézier based on the work of Paul de Casteljau.
These polygons can have a color fill, which is generally set using an additive or a subtractive color model.
- The additive color model combines 256 levels of red, 256 levels of green and 256 levels of blue
- The subtractive color model combines 256 levels of cyan, 256 levels of magenta, 256 levels of yellow and 256 levels of black.
Adobe‘s ubiquitous Artworking application Illustrator can work with either.
Besides the 256 levels of each color component, several applications use an extra Alpha level, also known as transparency level. Adobe‘s photo-editing software Photoshop makes an extensive use of Alpha transparency with raster graphics, while Illustrator doesn’t use it at all.
The competition has introduced Alpha transparency in vector graphics, allowing for example to fill polygons with gradients going from solid to completely transparent.
In the field of illustration, this can prove to be a time-saving feature, as it exempts the user to quickly create effects without ajusting the gradient colors to match the background.
In this example, the reader can see the difference between a light reflection created without and with Alpha transparency.
Inkscape, an Open Source and cross-platform vector graphics application, uses Alpha transparency and can export it to the universal PDF format, which is correctly rendered by Acrobat.
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