In the following Quick Tip you will learn how to create a seamless wood grain effect. This is a step-by-step tutorial which is perfect for beginners to Inkscape. Let's begin!
Start by importing the bitmap with your wood sample into inkscape. Use either File/ Import (Control + I) or just drag and drop it into Inkscape. Embed or link it. It's not going to stay in the file as we just need it for color reference.
Use the colour picker (F7) to pick a few shades from the bitmap and assign them to shapes (e.g. some circles).
Create a square and assign the base colour. This would usually be the lightest colour you picked.
Add some lines with the straight lines too. To match them perfectly you can use a duplicate of the square, convert it to a path, break the right hand nodes and delete them. Only the left line will remain.
Combine the shapes with the Path/ Union option (Control + +) and add more nodes to the lines
UseSelect a row of nodes, convert the lines to curves and move them slightly to create an uneven pattern.
The more you move the nodes the wilder the pattern will be. Change the lines' stroke width just little from on the next and then convert the lines to paths (Path/ Stroke to Path).
Use the colour picker and assign varying colors to the shapes.
Use the node modifier to add more variation to the lines by adjusting the thickness of the lines.
This treatment takes some patience but it gives it a more natural feel and is worth the effort when the material is shown close up.
There is no need to move every node as long as you achieve a less even pattern.
To reduce the contrast of the lines and blend the pattern with the background change the alpha setting of the fill colors.
Play around with pattern, the amount of movement in the lines, their thickness, colour and alpha setting to fine tune your material. Add gradients and shine to the texture if you don't need the wood to be seamlessly tileable.