Thursday, October 5, 2017

Virtual styling of bonsai using GIMP

These notes accompany a presentation given at the BRAT Top Ten day on the 30th of September 2017. At the BRAT day, I used photographs of Mack Boshoff's tree used for the demonstrations earlier in the day. Mack's final design, following a large marker pen sketch he drew in advance, looks fantastic (Mack did two or three hours worth of work after I took the photo I used for styling). I've made some styling decisions on the tree below for the purpose of showing how the software works

Drawing is an important part of designing your bonsai - laying things out on a page can help you understand your design and think through all of the implications of the design. There are many different ways to draw- pencil, watercolour, marker pens, ballpoint, charcoal. One method of drawing that has become increasingly popular is to use layer-based image editing to mock up a 'virtual styling' of your bonsai. Some bonsai professionals offer virtual styling as a service.

Layer-based image software is the most flexible and powerful way of editing photographs, used professionally to retouch and composite images for magazines, design mockups and advertising.  The gold standard tool is Adobe Photoshop, and if you have a license for Photoshop, most of these instructions can be used for working up virtuals there. This tutorial uses GIMP, a free layer- based image editor. You can download GIMP here (for windows, mac or linux), and there are some further learning resources here.

When you first launch GIMP, you can go to the 'file' menu, choose 'open' and select an image to work on.


Apart from the photo you are working on, there are two main areas on the screen where you will be working- to the left, is the tool bar - where the various selecting, drawing and editing tools are.

On the right, is the layers and brushes dock. Layers allow you to stack up transparent 'sheets' that you can draw on, switch on and switch off, move around independently of each other and use to have multiple options for your bonsai.

Photographs for image editing

Your tree should be photographed under bright light, with a well-contrasting flat background, at eye level, as close as possible to the intended front for your tree (remembering to consider a few different possibilities for the front).

Cropping your tree out from the background

Having imported the photograph of your tree, we want to 'cut it out' from the background, so that we can look at the tree without any distractions. GIMP has a number of different selection tools you can use to select the tree, then cut and paste it into a new layer (using the edit->cut and edit->paste-->as new layer commands). I find the foreground select tool and the select by colour tools to be the most useful in this case, but this video runs through how all of the selection tools work.

Once you have pasted your tree onto a new layer and switched off the old base photograph alyer, you'll see a grey checkerboard pattern behind the tree. This checkerboard represents the areas that are transparent. To avoid looking through the image to the transparency behind everything,  you can then create a new layer, lower it to the bottom in the layer dock, and use the paint bucket tool to paint that layer black (or white, or grey, or some other flat colour that contrasts well with your tree). This helps you see the foliage and branch structure cleanly without clutter. In general, deciduous trees in winter look best on a black background, while conifers look good on a white background if they have dark foliage.

It's always a good idea to make a copy of the layer before you work on it- so that you can go back to the original when you need to change it later. At the bottom of the labour toolbar isthe copy button- the two cards/squares on top of each other- select the tree's layer, then rpess this button and you'll get a copy of it. Move it to the bottom of the layer stack, so you have it to use later.

Changing the planting angle

We can use the 'rotate' tool to adjust the angle of the tree- select the rotate tool, then make sure that the tree's layer is selected before adjusting it. As you drag your mouse, you'll see the preview of the tree rotating so that you can choose the new growing angle.

Once you've done that, you can use the erase tool to erase the pot that is now at the wrong angle. We'll discuss putting it back into a pot further down in this tutorial

Bending branches

 In much the same way as we rotated the whole tree, we can select an individual branch, cut it and paste as a new layer (as we did above to select the tree from the background) and then rotate the individual branch. When you select the rotate tool, you will see a circle and crosshair: this is the point that the whole rotated layer will rotate around. You can drag this base point down to the base of the branch before starting the rotation. Using this tool, you can begin to set the 'skeleton' of your tree. 

Pruning and developing branches

There are two tools you will use to prune and grow your trees- the Erase tool, when selected, will allow you to shorten foliage pads, cut back branches, or remove whole trunks.

The clone or rubber stamp tool is a little more complicated to use but very powerful, allowing you to mask foliage pads that match the existing texture of the tree's foliage.

To use it, make sure you are working on the tree layer, select the clone tool, then hold down the 'ctrl' key and click on the source area you want to copy the foliage from. Now when you click and drag with the mouse, you will see a crosshair at the source, copying whatever is under the cursor and painting it where you move the cursor. You can use this to thicken or widen a foliage pad, or copy from one part of the tree to another to flesh out and refine a branch's foliage. Step by step demonstration here
after pruning and growing out branches with the erase and clone tools

Jins and Sharis

To make a jin or shari, you will select the area you want to jin (I find the Intelligent Scissors select tool to be the best one for this), then create a new layer, and use the paintbucket to fill the selection you have just made with white. This will give you a solid white shape overlaying where you want your jin and shari to be- which doesn't look very realistic- we'll be fixing that in the next step.

Instead of just switching layers on and off, we can use the layer overlay control to adjust how transparent your jin layer is. Slide the layer transparency slider down from 100%, watching the white jin sections until the transparency makes the jin look realistic- showing shadows and texture, but still showing a good contrast against the normal bark.


Finally, we can take an existing pot, isolate it in the same way as we did to select the tree, and paste it into this image. If needed, you can use the Scale tool to adjust the size of the pot to suit the tree. Now, you can also bring up the copy of the tree layer from before it was rotated, and erase the existing tree, and it's pot, leaving the landscaping under your tree. If you order the layers so that the pot is on top, the potscaping below, and the tree beneath that, the parts will all cover each other in the right order.

Saving your file

Once you are happy with your virtual styling, you can use the File->Export command to save a JPEG image for printing, emailing or sharing on facebook. Type the whole name eg. reallyawesometree.jpg WITH THE EXTENSION so that GIMP knows to export a JPG (or a GIF or PNG or TIF etc. if you want one of those other formats for some particular use). If you want to save the image so that you can come back later and work on the layers, you should use the File->Save command, and GIMP will save in .XCF format, it's own internal file format. Saving this way means that you won't easily be able to share this file over the internet- it is large, and most people won't have GIMP installed to view it- but you can come back at any time and all of your layers will still be available to use. The end result of my mockups above is available HERE as a 15 Mb XCF so that you can see how the various layers have been cut out and combined.

Friday, April 28, 2017

Bonsai: Restyling a fallen tree

This tree was one of my grandfather's favourites- it started out as the winner of the annual club Style of the Year competition in 1997. It was later exhibited at an international exhibition in Pretoria in 2003. Since I inherited it last year, I've been nervous to do too much work on it. I shortened some of the very obviously out of proportion branches, and lifted it out of the pot to rake out the roots and introduce a little fresh soil underneath. I also attempted an approach graft to try and get some lower growth as the tree had gotten very leggy over the years. Here it is today:

In preparation for a demo I'm doing at my club in September, I spent a bit of time mocking up some virtual options. In all cases I've rotated the main stem over closer to the horizontal and looked at either a long shallow bowl or a freeform slab. Finding a pot this size in a style I want will be anotehr story, but it's a few years away from a final pot- I want to get it into a deeper training pot next season so that it can grow with a bit if vigour.

Option 1: tidying up some of the stems/branches, jinning back or removing one or two others and then refining the foliage a bit
Option 2: some additional jinning, removal of excess branches and styling of foliage into more 'traditional' horizontal pads
 Option 3: Drastic shorting and removal of stem, lots of jin on what's left, a little bit of  refining with what's left. I think this goes too far but sometimes looking at an extreme option is a good way to understand what's possible and what works.
Option 4: Similar to option 2: some jins, thinning out of unnecessary branches, some additional growth.

Tuesday, May 17, 2016

Infrared KonTiki

 When the rain stopped on Sunday, I pulled out my Infrared camera and got a few shots of the Scout rafts on the water at Arrowe Park for KonTiki 2016.

Friday, May 13, 2016

Fitting a pickup in a Yamaha GL1 Guitalele

I was given a Yamaha Guitalele for Christmas in 2014 (because my wife is awesome like that), and I've been using it as a fun guitar for use at home and on camp. I'm looking at playing it at church, but to do that I need a pickup. Having looked around, I rejected the locally available generic piezo pickup options, and ordered a Fishman Isys system on eBay, because Fishman provide a completely system with great installation instructions including templates for all the cutouts, and a pre-wired pickup.

The system has three components- the pickup, the preamp, and the battery box and output jack. The preamp is intended to be installed on a flat surface, while the battery box has a slightly curved face. I started by printing the cutout template, checking the preamp fitted the template, then finding a relatively flat spot on the bass side of the lower bout to install it. Using a Dremel with a cutting wheel, and a set of jeweler's files, I cut the cutout to the template shape, then checked the fit of the preamp, filing the shape to fit.

Next was the battery box, with a more complex cutout. At the same time, I marked the pop for the screw holes, which I then drilled plot holes for. Meranti is brittle and tends to split of you attempt,to drive a screw without a pilot hole.

Next up is the under-saddle piezo transducer, which is installed after drilling a 2.5mm hole off to one side of the bridge, then passing it up from inside the body.

The saddle then needs to be lowered by 1.6mm- I marked off the height on both ends of the saddle, then sanded the base down until it reached the right height. All that remains is to assemble and string up.

All in all, it went smoothly, and the Guitalele sounds great acoustically and plugged in. Unfortunately,there is an occasional buzz, which might be my poor skills in setting the saddle. The Fishman set is design for a full-sized guitar, so there is a lot of loose cable rattling around inside the body, which might be also contributing to the buzz. I will probably shorten and re-solder these cables.

Tuesday, March 29, 2016

Fretless pickup mule

After a long break, I picked up the parts of my fretless project bass and moved towards completion this weekend. First step was to mount all the hardware on the neck, and test it out on my existing Squier James Johnston bass while I was busy.  
After that, I mounted the neck and bridge onto a piece of scrap timber, ready to experiment with pickup placement. Leo Fender used a rig like this to place the Precision, Jazz and Stingray pickups, finding the right spot by trial and error. I will use his positions as a starting point, using this useful graphic as a starting point: