transforming chicken scratches with photoshop

January 28, 2007 10:33 PM

How can I photoshop my kid's thin pencil drawings so that they look like they were drawn with a sharpie or thicker pen? I want to stick them on shirts at some point. Some of them are just funny and bizarre.
posted by mecran01 to Computers & Internet (16 answers total)

I think the new illustrator, will trace lines into computerized lines which you could then just adjust the stroke width. The photoshop option which surely exists isn't coming to me right now.
posted by magikker at 10:37 PM on January 28, 2007

Response by poster: I've got creative suite 2.3 (need to install it) so I will check that out, thank you!
posted by mecran01 at 10:41 PM on January 28, 2007

Best answer: This is it
posted by magikker at 10:48 PM on January 28, 2007

Inkscape is a free vector illustrating program that does this quite well.

In it, do this:

1. File --> Import --> Select the file you want to use.
2. Path --> Trace Bitmap
3. Play around with either the "Image Brightness" or "Edge Detection" modes. Click "Preview" to see what it looks like. Click OK when satisfied, and close the "Trace Bitmap" tool.
4. The new "traced" image will be pasted on top of the original bitmap. Move it out of the way and delete the bitmap underneath if you like.
5. To play with the thickness more, click:
Object --> Fill and Stroke
6. In the "Stroke Paint" tab, make sure "Flat Colour" is selected. Then in the "Stroke Style" tab you can select the line thickness.
7. When you're done, go to File --> Export Bitmap.
posted by Jimbob at 11:04 PM on January 28, 2007

I'll second Inkscape - it's great (and free). However, you mention Photoshop so this tutorial may help. I've used it on photo's and created sketches of varying types. There are a lot of interesting tweaks. I don't think it's exactly what you want but have a play.
posted by ninazer0 at 11:21 PM on January 28, 2007

One approach I've used for making lines thicker is to blur everything and then play with a tone-balance histogram to make everything below a certain level of gray turn completely black. Here's what I mean:

Starting image, 1-pixel wide black lines on white background

After a major Gaussian Blur

Here's how I adjusted the tone balance

And the result (Ta da!)
posted by Steven C. Den Beste at 11:42 PM on January 28, 2007 [1 favorite]

By the way, you can get different results as a function of what kind of blur you use and how you adjust the tone balance afterwards. Gaussian Blur is pretty crude as such things go, and that's why the places where lines intersect look a bit crummy in the example above. Other approaches to blurring can look better, more crisp.

The reason I like this approach is that it's fast and easy and the effort doesn't scale as a function of how complex the drawing is, or require mucking around with vectors. (On the other hand, it's much more difficult to make it work with multi-color pictures.)
posted by Steven C. Den Beste at 12:10 AM on January 29, 2007

I did this in Photoshop by using levels to simplify the drawing (blacks on a white background, few shades of grey), selecting the black pixels, and applying a stroke. Another approach might be to expand and feather the selection, then run over it with a black brush - this gives you better control if you want different pen weights.

To colour the image I created a new layer, roughly painted over the area I want to colour with a strong colour, and dropped the opacity of the new layer to about 10%.

If you go the Illustrator route, that first Levels step in Photoshop will still be useful.
posted by Leon at 3:01 AM on January 29, 2007 [1 favorite]

Been doing this in Photoshop for ages the way SCDB posted. If it's black and while, Gaussian Blur, then Levels. You should always be able to get smooth (antialiased) edges, but line ends will always be rounded, which may or may not be a bonus.

It has the added bonus of being able to clean up any scanning noise, and you can repeat it pretty much indefinitely to get the right thickness.

I've usually found auto-tracing bitmaps to be trouble, and require more clean up than was practical, unless the persons drawing, scanning, and cleaning them up knew exactly what they're doing.
posted by Ookseer at 3:13 AM on January 29, 2007

If you're at all artistic or even just plain careful. You could trace the drawings with a sharpie first (by hand). Then scan and print to your heart's content. It's probably not very hard.

If you're just starting out, get some tracing paper and then you won't ruin Jr.'s picture either.

If the images are in color or on cheap (newsprint) paper, you might have better results with this technique.
posted by zpousman at 5:19 AM on January 29, 2007

I would suggest magic-wanding the white space and inverting your selection. At that point "expand" the size of the selection by any number of pixels and fill it with black. That would produce thicker lines.
posted by cusack at 8:56 AM on January 29, 2007

you could always just photocopy the drawing and then manually go over the lines with a sharpie. (alter the photocopy, preserve the original). then scan in the sharpie'd version and go from there.
posted by twistofrhyme at 9:14 AM on January 29, 2007

I've done exactly what twistofrhyme recommends and it worked perfectly.
posted by Rock Steady at 9:55 AM on January 29, 2007

I third the blur-and-levels approach. The "Minimum" filter might also be helpful for this. (It's hidden at the bottom of the Filters menu, under Other.)
posted by bink at 10:01 AM on January 29, 2007

Response by poster: Thank you everyone, multiple great answers! I will post the results in this thread.
posted by mecran01 at 1:37 PM on January 29, 2007

Response by poster: update: my kids are making simple pencil comic strips after attending a library-sponsored comic workshop, and I am looking forward to trying this stuff out tomorrow.
posted by mecran01 at 10:46 PM on March 3, 2007