can aperture 3 convert a gray scale photo into a line drawing?

Do you mean a line drawing of the contours or a kind of pencil sketch?

There s no built-in command in Aperture to do either. For operations that go beyond adjusting an image to perfection you use plug-ins or external editors.

For example:

An original image and the results of using the Toonit!-plug-in, the Quartz composition filter "Color pencil", and "Edge detection" in Adobe Photoshop - left to right:

Regards

Léonie

If you really want to do it in Aperture, you can try to play around with the "Curves" adjustment and map all but a few intensity values to the color of the lines that you want, but that would be hard work. Just to give you an idea:

A better(?) example of extracting lines and object contours in Aperture with the "Curves" adjustment:

In this case the background is lighter than the statue in the foreground. The histogram shows two distinctive peaks - one for the lighter background pixels and one for the dark pixels of the statue,

To extract the contours as dark lines on a white background, you will have to map the pixels in the valley between these two peaks to "Black" and all other pixels to "White". Set the channel to "RGB" an drag the curve in the valley down to zero and outside this reagion up to 255 (White). The curve will wiggle a lot, so will have to use many points along the curve to tame it.

Also keep in mind Aperture is not designed to work on grayscale images. See Aperture: Unexpected results when working with grayscale or other non-RGB images

Aperture is not designed to work on grayscale images.

Good point, Frank!

Here is a good technique for photoshop:

http://www.luminous-landscape.com/tutorials/new_page_9.shtml

jimmyjackcorn wrote:

can aperture 3 convert a gray scale photo into a line drawing?

And now that this thread is answered, a small plea: a line drawing is made by hand. My hands have made them. My computer has not. It cannot. Honestly -- anyone who mistakes photos converted to "line drawings" or "watercolors" or "paintings" is simply ignorant. That such ignorance is now accepted does not excuse it.

Here is a good short piece on drawing, with many excellent illustrations.

The phrase I suggest the OP use is "line art". This is a graphics term. Line art is to drawing what clip art is to painting.

End of plea. Thanks for your attention.

Hi. What you say is well-put: not only do I agree, but I think the phrasing and timing of my comment show that. Please carefully re-read what I wrote. Thanks.