GMIC Water color filter tutorial on using the filter andhow similar effect can be created using Gimp GMIC filter programming: Tom Keil Tutorial: Arto Huotari
Section 1: GMIC Water color filter GMIC water color filter creates channels of Cyan, Magenta and Yellow and mixes them to each other for different colors. Water color like effect is created by preliminary preparation of the image and textured masks created with Cubism and Fuzzy frame filters. For deeper understanding it is recommended to read through the second section of the tutorial. Whole range of the effect is presented in video “Travel in water color” by Zonder.
GMic Water color filter, learning the filterSince the filter has a lot of settings it may be that for your image the filter does not producedesired results with the default settings. This tutorial aims to help new user to produce someresult and hopefully lead to quicker learning of the filter.Start by setting all sliders to left except Cyan Stroke Strength, Magenta Stroke Strength andYellow Stroke Strength. Set these sliders to the right. Preview should now look black. Nextslide color intensity slider to the right to get colors to the preview window
GMic Water color filter, learning the filterNext go to the Color brushes settings section and slide the edge distance sliders. Start withthe strongest color and proceed to weaker colors next. Move the sliders so that you havethree stacked boxes of different size.
GMic Water color filter, learning the filterNext set the abstraction setting to your liking. Again start with the strongest color
GMic Water color filter, learning the filterNext increase the brush size to merge the grains of individual colors
GMic Water color filter, learning the filter To complete the color settings move the stroke strength sliders to left in order to smooth outand weaken the colors.
GMic Water color filter, learning the filterSet paper color, texture and invert colors settings. Then revert back to the top of the dialogueand adjust Light colors slider at least to 0.01. Note that the effect of the slider may not belinear. Note the difference between 0.05 and 0.06. This is caused by high color intensity andzero dark colors setting. Adjust color intensity settings and click OK to process the image
GMic Water color filter, learning the filterFinal image processed with the previous values
Section 2: Creating the effect in Gimp.Base image used in this tutorial is 1164x947 pixels. For larger images effectproduces different results and different values for parameters should be used.
Step 1: Reduce the detail of the image using selective Gaussian blurDuplicate background layer, select Filters → Blur → Selective Gaussian blurSlice of unmodified image is shown on the right. Blur was done using with radius10 and delta 30
Step 2-1: Enhancing and bringing out the remaining detail. Duplicate the layer.Filters → Edge detect → Edge → Sobel (with value 3 in this case)Edit → Fade Edge→ Dodge (middle slice)Set layer mode to Value (right slice)
Step 2-2: Enhancing and bringing out the remaining detail. Duplicate the layer, Set layer mode to burn Filters → Blur → Gaussian blur (value 5) Filters → Edge Detect → Edge → Sobel (3) Edit → Fade Edge → Divide Right click to layer → Add layer mask → Gray scale copy → Invert colors → AddPrevious Burn Blur Sobel Masked Divide
Step 2-3: Enhancing and bringing out the remaining detail. Duplicate the thirdlayer in the stack. Move it to top, set layer mode to DevideFilters → Blur → Gaussian blur (value 10)Filters → Edge Detect → Edge → Sobel (6)Edit → Fade Edge → DivideRight click to layer → Add layer mask → Gray scale copy → Invert colors → Add From step 2-2 Step 2-3 final
Step 2-3: ExplainedBoth blur value and edge detection intensity were increased from previous step. Ifwe look in to the images with out masks a difference can be seen.Image on the left has smaller blur value and edge detection intensity. There aremore detail edges present and the edges are thinner.
Step 2-3: ExplainedOn step 2-3 layer mode divide was used instead of burn. By zooming in to theimage and changing layer modes the difference can be seen.Different layer modes give different results. Idea here is not to use only burnsince using burn only creates very dark and strong edges. Our target is to createwater color like image we want to enhance the edges with out making them toodark and sharp Before Divide Dodge Burn Value
Step 2-4: Continue duplicating the third layer on the stack and use increasing blur and Edge Detect values until the layer bitmap is white after divide. Disregard the white layer. With the example image, blur value 40 loses all detail.There are multiple ways to vary the layer stack. Layer mode of each layer affects the endresult, also different result is produced if the visible result (edit copy visible) of previousstep is used instead of third layer in the stack for each new enhancement layer (paste asnew layer). Now is a good time to save the image and also save it to different name andcontinue with new copy.
Step 3-1: Spread strong colorsBlank the background layer. Select one of the visible layers, right click and select“merge visible layers.”
Step 3-1: Spread strong colorsDuplicate the layerBreak the image to LAB channels.Colors → Components → Decompose → LABBlank A and B layers and select L layer.From tool box select tool “select by color”Zoom in to the image and select as dark pixel you can find and set the selectionthreshold to your liking. For sample image the L channel was very light so I usedthreshold of 30. Idea here is to simulate the spread of strong water color becauseof absorption to paper.
Step 3-3: Spread strong colors, recompose the image. Select → None Unblank the A and B layer Colors → Components → Recompose. Note that this will compose the image to the layer it was originally decomposed from. It is recommended to rename the layer now to “From LAB”OriginalModified
Step 4-1: Move to CMY color space / preparationDuplicate the “From LAB” layerInvert colors of the “From LAB” layerAdd new layer with a black colorAdd new layer with a white colorBlank the black and white layerActivate the “Inverted From LAB” layer.
Step 4-2: Move to CMY color space ... / create color layersSwitch to the channels tab and blank Green and Blue channelsEdit → Copy VisibleEdit → Paste as new layerMove the layer on top of black layerRename the layer as CyanBlank the layerSelect “Inverted From LAB” layer
Step 4-3: Move to CMY color space / create color layersRepeat previous steps for green and blue channelSwitch to channels tab and blank Red and Blue channelsEdit → Copy VisibleEdit → Paste as new layerMove the layer on top of black layerRename the layer as MagentaBlank the layerSelect “Inverted From LAB” layerSwitch to the channels tab and blank Red and Green channelsEdit → Copy VisibleEdit → Paste as new layerMove the layer on top of black layerRename the layer as YellowBlank the layerSwitch to channels tab and turn on all channelsSwitch back to layers tab and add black mask to Cyan, Magenta and Yellow layersFinal layer stack is shown on the right
Step 4-4: Move to CMY color space / set layer modesUnblank the layers and set layer modes as shownYour image should be completely white now Difference Addition Addition Addition Normal
Step 5-1: Create line artUse your favorite method of creating the line art and place it on top of layerstack. Use the original image to create the line art.This was created byFilters → Blur → Selective Gaussian Blur 3 with delta 15Filters → GMic → Artistic → B&W Pencil with default valuesColors → Levels to lighten the sketch if necessarySet layer mode to Multiply
Step 6-1: Use water color brushes to paint out the colors. Use white color to painton the black masks of the Cyan, Magenta and Yellow layers.Final image and final layer stack shown.Note that also red, green and blue can be added to color layers as has beendone here to bring to make the water look blue instead of brown.