© Jan Esmann and Power Retouch. All rights reserved.

Photoshop plug-ins for retouching


Quick introduction

This Photoshop plug-in draws edges around objects in three different ways and converts the photo to a graphic image. This is the Edgeline Photoshop plug-inís control panel. Click on the image for a larger view. It works with the following image modes: 8 & 16 bit/channel: RGB, CMYK, Grayscale, Duotone, Lab.

Three edge drawing methods

The drop down menu lets you select one of three methods.
Enhanced LaPlace † is a variation of the classic LaPlace edge detection algorithm with the improvement that it tends to draw the lines on the inside of edges instead of splashing out on both sides as Find Edges does. Also it avoids enhancing noise to a large degree. Toneline Lithfilm †emulates traditional tone line lithfilm prints with four different exposure directions. Edge detection †is a variation of the traditional edge detection method. Tone line and Edge detection produce two-colored outputs. The colors can be changed.

Output color

These controls also vary with the selected method. Black on white †will draw in black lines against a white background. If using the
by default be set to the foreground and background colors in the host application. If you have changed the colors by clicking in the small colored rectangles, you can revert to the hosts foreground and background colors by clicking on the Reset button Transparent background † - this checkbox is only available if you work on a layer above the background. It is useful for all kinds of graphic design and when you want the output result to be saved as a gif image for web-design. The portrait to the right has transparent background and is done with the Toneline method. If you have an image that's larger than the final result should be, then know it's always best to do edge lining before size reduction. This portrait was downscaled 400% after edge lining with the lith film method.

Enhanced LaPlace

This produces varicolored edge lines of varying thickness. Superficially it resembles traditional edge detectors like Find Edges, but where the traditional ones draw edge lines along both the outer and inner sides of an edge, we have changed it so that it tends to produce edge lines along the inside only. This produces no blur when the images are combined, in fact it can sharpen certain images a lot (see below). Also compared to other traditional methods like Find Edges, our method keeps lines thin which also gives sharper results. The lines drawn will preserve some of the original color, which can be useful for correction layers since they blend in more naturally. Traditional Find Edges swaps colors from the inside of the edge to the outside and thus produces hazy results.

Edge enhancement

Edge enhancement is a technique to trace edges with the intention of giving the photo a sharper and more defined appearance. As you can see the original can be rather unsharp and the end result will still appear sharp and crisp. The end result has not been sharpened or modified beyond what is stated above. It gives the best results on images with a lot of details, like this one.
Edge enhancement 40%
Original photo.

Toneline (lithfilm emulation)

Toneline is a traditional darkroom technique involving two sheets of lithographic film, "lithfilm". Lithfilm has an extremely high level of contrast. The first sheet is a regular negative, the second is a negative of the first negative, hence a positive film. Since they are black/white and negatives of each other, if you place them on top of each other, no light would come through at a regular angle, but if viewed at an oblique angle a thin line of light would pass along edges. Toneline is a printing technique that places the two lithfilm sheets together on top of a sheet of photographic paper. If you exposed directly from the top, no light would come through, but if you expose the paper from an oblique angle, light will pass through the thin celluloid film gap where edges meet. The final tone line image depends on the direction of exposure. The exposure angle will determine the width of the line and the direction determines which edges will be exposed.

Edge detection

This will simply trace all discernible edges with a line of definable width and color. It can roughly be understood as a tone line lithfilm exposed in all directions instead of just one. It produces thicker lines than the Toneline method. These can be thinned with the Clean-Up options.


This combo box offers you the traditional clean-up methods thin, thin more, dilate and erode. They are best used with the strict two color methods, not enhanced LaPlace
Toneline, no clean-up
Toneline & thin
Toneline & thin more
method Enhanced LaPlace then the lines will not all be pure black, but the background will be set to white. Color † will let you select a color for the line and a color for the background. When used with the Enhanced LaPlace method, you will only be able to set the background color. The two colors will