By Graham K. Rogers

I am looking currently at some apps that produce images from photographs that look like hand-drawn pictures. Some of these are better than others, although in most cases - as with the use of filters - the output is subjective. What I like, you might not. Thus far I have examined My Sketch, AA Sketch and Camera 4 Line Art although one of these, AA Sketch appears to have a clone in the iTunes app store.

As I wrote in the introduction of the first of those articles, my own skills at drawing are rather limited, although sketching to outline concepts or convey ideas to students is within my grasp.

Although I am not by any means artistic, I have downloaded a number of apps (e.g. Brushes, iSketch) that allow drawing and sketching. One basic app that I have had on the iPhone for several months takes the idea of drawing with charcoal and creates the effect on the iPhone screen. In the context of the other apps that produce drawings from photos, this is worth a mention.

Confusingly (see above) the name of this app is ASKetch (with three upper case letters). It was developed by Andrew Kern and there is a useful video on the developer website.

The beauty of sketching with charcoal is the way that effects are created by shading, erasing, and by the use of pressure when applying the charcoal to the paper. An artist skilled in the use of the medium can quickly create a drawing that appears to be in 3D with the subtle gradations in the levels and thicknesses of the grey.

The app works in pretty much the same way on the iPhone and the iPad, except that there is no messy black to worry about. The app opens with a blank screen (portrait or landscape). It is completely blank; just white. Simply dragging one's fingers across the screen, draws a black line. As pressure is applied, so the output becomes thicker and darker.

The tools provided are hidden. This provides a completely uncluttered working area. To access the simple tools, the screen is pressed with two fingers. Most of the drawing control is applied using the first icon on the left. This selects the thickness of line or shading and is changed by swiping to the side. When this is live, the eraser icon alongside is greyed out. When the eraser icon is pressed, the drawing icon is greyed out.

In the center of the toolbar is an undo/redo button. Like the drawing tool, swiping to the side changes its function. Between this and the Trash is an icon that looks like a landscape. This accesses works that have already been created and from here, a new, blank screen can be selected.

When working on an image, pressing the screen will allow it to be copied. This can be pasted into another app: for example an email. When the previously saved images are displayed, pressing any one brings up three options: Export (save to photo library), email or Tweet.

The ASKetch app is simple to use, but the output it allows can be as sophisticated as the skills of the user/artist will allow. The beauty and sophistication of this $1.99 app is in the sensitivity to pressure input. Now I have to learn to draw.

Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand where he is also Assistant Dean. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs.