#TURN PHOTO INTO SKETCH WITH GIMP HOW TO#
#TURN PHOTO INTO SKETCH WITH GIMP FREE#

We put our original image back in the background, and set the white layer to overlay (as we see here) - this means we can see the coloured areas behind the white layer - this is extremely helpful when we’re painting the white layer, as sometimes the edges are rather fine, or are in the middle of an area that’s more or less the same colour. Images,original image & colouring layer in overlay mode L&C dialog with set-up for the colouring trick ¶

For the colouring, we need some more work (mostly slogging, though). We could stop here, and this is a decent sketch effect. It’s shown here with a white layer behind it. To do this, open the Layers & Channels dialog (if it’s not open already), and add a layer mask to the layer with the inverted edge detect layer ( Edit -> Copy with the highpass layer selected, Add Layer Mask with the inverted edge layer selected, then select the mask and Edit -> Paste) Since we kept the strong edges in the highpass filtered layer, this means that we end up with a rather nice black-on-transparent layer. Invert the Sobel edge detect (you did keep a copy, right?) with Layer -> Colors -> Invert and apply our highpass-filtered copy as a mask. Small trick to get to black-on-transparent. The only problem is it’s white-on-black, when we want black-on-transparent ideally. Just drag the mouse/pen along the bottom of the curves tool.

#TURN PHOTO INTO SKETCH WITH GIMP FREE#

We set the curve type to free (which allows discontinuities), and then for the bottom 3/4 of the curve (or thereabouts) to 0. The easiest way to do this is with the curves tool ( Image -> Colors -> Curves) like this. To get them, we eliminate the edges with small magnitude. We only want the strong edges, otherwise it’ll look crap.

#TURN PHOTO INTO SKETCH WITH GIMP HOW TO#

Curves window for how to do a highpass filter ¶ Equalised & desaturated Sobel ¶īring out detail with an auto-equalise ( Layer -> Colors -> Auto -> Auto-Equalize) of the sobel edge detect, and convert it to greys using desaturate ( Layer -> Colors -> Desaturate). Straightforward Sobel edge detect ( Filters -> Edge-Detect -> Sobel) of original (don’t forget to save a copy of the original) The Sobel edge detect should be done on the background image (without an alpha channel) rather than a copy of the background (which has an alpha channel). Tutorial on how to make a nice baby & daddy photo into a nice baby & daddy painting. Text and images Copyright (C) 2002 Dave Neary and may not be used without permission of the author.

Turn photo into sketch with gimp