Thursday, October 8, 2009

GIMP Experiment: Dealing With Line Drawings

A comment came up on the GIMP Registry asking about scripts for working with/creating line drawings in GIMP. As is usually the case, people want to know if what they can do in Photoshop can be done in GIMP. And most always, the answer is yes, but...there are x amount of methods in GIMP to arrive at the same effect done in Photoshop. So I went hunting for a few Photoshop tutorials that would give me comparable effects/functions/or filters to GIMP, to experiment with. First stop, Lunacore.com, using very simple methods/filters, I might add. I'll use the clock as the example for this experiment. Feel free to follow along, if you want.

The watch piece:



Lunacore's method to get the line drawing using Photoshop:
  1. High pass filter (radius of .3)

  2. Sketch to notepaper

  3. Threshold level of 180
Here is that result:


Here is the same process using GIMP:
  1. High pass filter (radius of 2, with -100 Contrast adjust, mode Grayscale)

  2. Quick Sketch filter by Harry Phillips and Michael Schumacher (Gaussian blur between 30-45)

  3. Colors/Threshold of 124

The result of those settings:



Judge the results for yourself.

A second Photoshop approach can be found at VirtualPhotographyStudio.com. This involves the "Old School" method and I featured a similar Paint Shop Pro version of this process here.

The Old School method is fairly simple:

Convert the image to greyscale.

Duplicate the image layer.

On the top most image layer, convert it to a negative image (Invert).

Change the blend mode to Dodge.

Go to Adjust – Blur – Guassian Blur – set to 15.

Select bottom-most image layer.

Go to Adjust – Blur –  Average – set to around 5. Use preview and make your own judgement.

To darken the grays, use Brightness and Contrast, by lowering brightness and raise contrast to bring in the black.

It might help to add some texture to the lines if you feel the image is too crisp or you could tinker with the levels (Color/Levels) by making adjustments using curves.

The same watch piece using the above process:


This looks fairly crisp. Usable as a line drawing?

I've had similar luck using a different method, altogether. It involves :
  

  1. Use Edge Detect (Laplace)

  2. Run Quick Sketch

  3. Use Colors/Levels adjusting with curves. (Tinker with it until you're happy with the results)

The result of that process look like this:



Looks very similar to high pass process shown above.

If I find additional tutorials that show better methods for obtaining line drawings in Photoshop, I'll share it here.

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If you intend to comment to complain about being unable to perform certain steps with tutorials, please explain where you are in the step process and what step you are unable to get to work correctly, instead of saying something like, "I can't do this!". Your comments will help get tutorial corrections made and help give clarification to future viewers who may have trouble in the same locations. Thank you. :)