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An Eye with GIMP (tutorial)

18 Oct

An experiment with creating an eye texture for a project. Not complete yet, and it needs work, but it looks promising and may be of use to someone.  I didn’t keep exact details the first time, and my first attempt (above) came out better than this one. Typical! I’m sure some of these steps could be done differently and/or better, but this is the way I did it.

  • Create a new image, 800×800, standard RGB, fill with black.

  • Filters, Noise, RGB noise. Set the Red, Green, and Blue sliders right across to 1.00.

 

  • Filters, Blur, Motion Blur. Linear, length=50, angle = 90. (The blur must be vertical).

  • Filters, Blur, Motion Blur. Linear, length=25, angle =270. (Some tutorials on the net recommend doing the motion blur a second time, backwards, to tidy things up).

  • Colors, Adjust brightness and contrast, brightness=50, contrast=30.

  • Create a new layer, name = “Centre“, fill type = transparency.
  • Use the blend tool, foreground = black, gradient = FG to Transparent, shape=linear.

  • Draw a line straight down from the top to about 200 pixels down.

  • Create a new layer, name =  “Outer
  • Draw a line straight up from the bottom, again about 200 pixels long.

  • Flatten the image (merge the three layers into one).
  • Filters, Distors, Polar Coordinates. Circle depth=100, offset angle=0, TICK Map from top, TICK To polar.

  • Colors, Colorize. Hue=35, saturation=50, lightness=0.

  • Add a new layer, name = “Pupil“.
  • Use a circular selection to fill the centre with black.

  • Remove the selection.
  •  Filters, Blur, Gaussian Blur, blur radius = 20.

  • Add a new layer, name = “Catchlight”.
  • Use the paintbrush, color = white, hardness = 50, size  = 100. Draw a squiggle for the catchlight (reflection in the eye from illumination).

Macro with Magnifying Glass (Dandelion)

16 Oct

I’ve always wanted to try macro photography but I don’t have a suitable lens. I’m using a friend’s Canon DSLR and it’s not worth buying a new lens when it wouldn’t fit the camera (a Sony) that I’m planning on buying myself. As always, there’s a way around the problem. There are a number of posts around the web about using a magnifying glass, combined with the usual lens on your camera, to do a “poor man’s macro“.

  • The setup, showing lens, dandelion, black card for background (held up by two marble blocks), and power supply:

I went hunting around in my “mirrors and lenses” box and found the top lens from an old overhead projector. Not a huge magnification but good glass and a good 75mm (3″) across. That makes it just a fraction wider than the inside of a roll of masking tape. Some hot-melt glue to fasten the masking tape roll to a metal box and I was good to go. Illumination was a 125W halogen worklight and a small 12V 50W halogen powered by the computer power supply in the background.

  • View from the camera (with room lights on).

Yes, that’s more masking tape holding the lens to the mounting.

  • A couple more shots, with various lighting and colour tweeks.

Tree Splodge

11 Oct

This may prove useful to someone, in some bizarre set of circumstances. This is an image transformation done with the free GIMP editor.

  • Starting with a photo of a whole bunch of trees

  • Mirror one side of the image onto the other. In GIMP, the best way to do this (that I’ve found) is:
  1. Duplicate the layer.
  2. Add an alpha (transparency) channel to the new top layer.
  3. Transform (flip horizontal) the top layer.
  4. Create a rectangular selection, then type 0, 0, <half the width>, <all the height> into the text boxes for selection size.
  5. [Delete] which will take out the left hand side of the top (reflected) layer.
  6. Flatten it down to one layer again.
  • Here’s the mirrored image:

  • Resize to a square image, in my case 2048 x 2048.

  • Flip vertically so there is sky at the bottom

  • Now, the key ingredient, Filters – Distorts – Polar Coordinates

Circle depth 100%
Offset angle 0°
Map from top
To Polar

  • Followed by a little trimming to get rid of the sky and clouds

  • And converted into a “splodge” the same way

Adding trees to a sunset

6 Oct

The problem:

  • My wife said: “Hopelessly overexposed, but the trees look nice. Perhaps you could replace the sky?”

Steps I took:

  • Here’s a sunset shot from the same evening, with some nice dramatic clouds, but a bit naff at the bottom.

  • Make a copy of the “trees” image and convert it to greyscale.

  • Select the main chunk of sky, staying away from the trees, and change it to white. Red is just to show the selection I used.

  • Use a round brush (in my case 50 pixels) of white to refine the edges around the trees and change it to white.  It’s better to eat a little tree than to leave a splodge in the sky. This is also a good time to clone out any annoyances in the image, in this case a roof and chimney.

  • Adjust the contrast. I used +50%.

A note on alpha masks:

  • If you’re not familiar with alpha masks (masks for short), these are just a 2 dimensional pattern of transparency. They can vary from opaque to transparent and anywhere in between. Each pixel location gets its own level of transparency. Conveniently, you can display, edit, and convert from/to as a greyscale image.

A mask can cover a layer completely or with varying levels of opacity. The grey value of the mask determines how much it covers. Where it is black, it completely masks the layer, producing a transparent area; where it is white, it leaves the layer unmasked (in its original state); where it is grey, it produces a semi-masking effect, with the transparency increasing as the grey becomes darker.   (from the PaintShop Pro help)

My first, failed, attempt:

  • I took my “trees” image and created an alpha mask (in Paintshop Pro that’s [Mask], [New], [from Image] and select the greyscale picture). This leaves just the trees on a transparent background.

  • Then I slid a copy of the “clouds” image BEHIND the masked trees, and moved it down a bit to provide a background. As you can see, it didn’t work, especially in the trees at the right.

  • I tried various techniques of blurring the mask, or having multiple layers with different masks, but nothing worked well.

A better way:

  • I took my “scrolled down clouds” image.

  • And I applied the tree mask to that (inverted, of course). This gave me a cloudscape with holes.

  • And then I just put a background layer of black BELOW the masked clouds.

  • A final crop and the result looks – in my opinion – better than either of the source images.

Quick and Cheap Mounting for Laserprints

1 Oct

There are all sorts of fancy, and often expensive, ways to properly mount your photos. However, sometimes you just want a way to tidy up a printed image. It doesn’t matter that it’s not archival and may die after a year – you can always print another one. This is how we’ve mounted a few recent pictures. No guarantee of longevity but that’s ok with us – we plan to cycle at least one new picture onto our walls every month.

  • Find out the heaviest card that you can print through your laser printer (in my case 170GSM) and that you can buy cheaply (in my case 160GSM), and print your picture out on this A4 white card. If your printer has manual feed options for printing heavier materials, you will want to use them.

  • Here’s a table full of requisites:  The printed A4 picture, black A3 card, metal ruler, pencil & paper, glue stick, paper cutting device (knife or guillotine), a sheet of glass, and a couple of heavy weights with straight edges (in this case samples of granite benchtop). Also required, a cloth and (in my case) magnifier.
  • All printers have an “unprintable area”, in my case about 6mm, at the edges of the card. Unless the picture happened to be exactly the same aspect ratio as the paper, there will also be a wider white strip at top/bottom or sides. These look ugly – but don’t just chop them off. Measure outwards from the printed image for 2mm.

  • And cut the card back to leave just the 2mm of white along the edge.

  • Repeat on all four sides.

  • Now measure the dimensions of your trimmed photo, and also the dimensions of the A3 black card (which should be 420mm x 297mm).

  • Calculate the offset from top/bottom and sides. Ii.e. left offset = (width_of_a3 – width_of_picture) / 2.

  • Put the black A3 card down and position heavy, straight-edged objects in from the edges by the calculated offsets.

  • Apply glue-stick to the back of the printout, paying particular attention to the edges (a waste piece of paper helps). This is a $2 stick of “Amos” brand glue.

  • Place the trimmed and glued printout carefully onto the backing sheet. You don’t want to get glue anywhere but underneath the printout as it will show on the black.

  • Burnish flat with a piece of cloth (here, a tea-towel). Laserprinter toner is melted plastic – it doesn’t rub off easily.

  • Place a piece of (clean) plate glass over the picture to press it flat. This piece is out of a flat-bed printer.

  • Put some heavy-ish objects onto the glass to press everything flat. A sheet of paper protects the glass from getting scratched. There’s about 3kg used here.

  • Leave for 30 minutes (min) to 24 hours (max). I haven’t noticed much difference. Final result is as below. Bonus for us, if when we have another earthquake, these won’t do any damage when they fall on your head!

Some Experiments with Oil and Water

30 Sep

I’ve seen a number of post on the net about photographing oil and water. This article “How I create My Oil & Water Abstracts” is particularly helpful and very pretty.

Seized by the urge to take some photos, Barbara and I hauled out some lighting, a glass container, water, oil, and food colouring. Some of the photos, purely by accident, ended up quite interesting. Setup details below, but first some more pictures to show the range of images we found:


Camera Setup

This was all set up in the kitchen, with what was to hand. A major factor is that, though a friend has lent me her nice Canon EOS 10D, I don’t have a macro lens or off-camera flash for it. Most of the examples I found on the net were of macro shots (some looking very pretty), but that wasn’t an option. We set the camera up on a tripod, as close as possible. One of the ubiquitous plastic “storage cubes” held the glass dish above a 125W halogen worklight, supported on a plate of glass (one of many salvaged from flat bed scanners).

The dish was the lid of a pyrex casserole dish, so it could take the heat. We didn’t know if the glass sheet would stand the heat but if it didn’t, the cube would hopefully contain the debris (especially after the water hit the hot 240V halogen bulb). The first box we used was red, rather than black and that caused quite an interesting tint to some of the images. We also tried inserting a yellow or blue cardboard sheet at one side of the box to add colour variation. The photo above shows a sheet of paper between the glass and the dish – that didn’t work very well at all and we left it out later. Note that the photo above is a composite – with the light on there is a tremendous glare that hides the details.

The accident was that, still being rather a noob at photography, I forgot to reset the aperture from when I was taking landscape photos in the morning. All the photos above were taken at 1/22 aperture which is very small for this setup. Since the camera was on Aperture Priority, the shutter speeds were very slow, generally ranging from  1/20 sec to as slow as 1/5 sec. This caused some really interesting swirling light traces as we stirred the mixture.


Playing with Photoshop

While playing around with these and other photos we took (about 95 for the session), I ended up with this image, which my daughter titled “High Velocity Alien Blood Splatter”:

A Little Practice with the Clone Tool

25 Sep

This is Linwood Avenue, a pleasant but busy road near my home in Christchurch. Two rows of trees, with daffodils planted amongst the grass between them. However, there’s a two lane road on each side of it, then surburban houses. The blocks are a reasonable length – a few hundred metres – with signs on the cross streets. I decided to practice my cloning skills by extending the trees and removing the cars, streets, and houses.

Here’s the source photograph, taken from slightly off-centre and with the camera about 400mm above the ground:

As well as copious use of the clone tool, I used GIMP’s resynthesis plugin which helps build chunks of texture out of sample areas. That helps avoid the dreaded “regular pattern syndrome” which can easily occur when cloning.

When I had a reasonable looking image, I copied it, shrunk it to 25% size, and blurred it:

That section got pasted into the distance of the image, roughly along the lines of perspective.

And this is the result (so far):

I expect I’ll try some more of these to improve my skills.

A Test of Character

22 Sep

This theory (from August 1931 Popular Mechanics) is rather strange, but – without actually trying it – who knows whether it worked?

Color-Matching Test Shows Your Character

Color sense, the ability to match various tints of colors, has been found to have a definite relation to character, since it indicates mental balance. Dr. William S. Wadsworth, coroner’s  physician of Philadelphia, has evolved a color test to guage a man’s mental make-up and show whether or not he is capable of certain acts. From the results of such tests, he claims, it is possible to determine whether an individual is mentally well-ordered, whether he is whimsical and, aside from showing possible criminal tendencies, demonstrate also if he is fit to be put in a position of trust upon which the lives and safety of others may depend.

The equipment consists of a blackboard on which are pasted ten colored slips of paper with a small box back of each slip. The person taking the test is handed a package of 100 slips of tinted paper and asked to place in the receptacle the tints most nearly matching the sample in front of each. After the test, the papers are pasted on a large chart, each near the sample with which the person associated it. Provided the individual is not color-blind, he would be classed as whimsical, unstable and unreliable if he placed orange tints near greens and blues near yellows. The combinations may reveal a hysterical extent. Some artists and painters taking the tests have shown a queer color sense, and one etcher who works in blacks and whites was found to be color-blind.

Survival

18 Sep

Three articles on using what’s around you for survival in an emergency:

From “Popular Science“, February 1963 source

How to survive a blizzard using your car and your head

  • Conroy fits face mask while Leo Morin makes warm clothing from seat upholstery.

Stranded in a snowstorm in your car, how would you survive? Don Conroy, Air Force survival specialist at Hanscom Field, Mass., suggests you tear the car apart.

Snowshoes can be improvised from fiberboard cut from inside the doors, face masks and mukluks shaped from the ceiling lining. Seat covers can be ripped into strips for leg and foot wrappings; upholstery padding can be made into warm boots.

Conroy has one more tip: Remove the spare to a safe distance. Fill a hubcap with gas by disconnecting the fuel line at the carburetor and pressing the starter. Dump the gas on the tire to start a long-lasting and bright signal fire.

  • Serviceable snowshoe is improvised from fiberboard panel cut from inside car door. It’s tied to a boot with strips ripped from the seat covers.


From “Safe Flight International”  source

Survival Uses for Aircraft Parts

PROPELLER:  SHOVEL, SNOW CUTTING TOOL, BRACING FOR SHELTER

WING TIPS:  WATER COLLECTION AND WATER CARRIERS

etc, etc


From the very amusing “The Art of Manlinesssource

How to Use a [BUSTED] Cell Phone to Meet 5 Basic Survival Needs

Each cell phone also had a circuit board.  I used the circuit board from a SmartPhone to make two very useful items to a survivor.  I noticed that when I abraded the edge of the circuit board against a smooth rock it actually ground down to a fairly decent cutting edge.  I used half of the circuit board to make a useful cutting tool which I used to gather and cut some natural bark cordage and also scrape a pile of very fine fire tinder shavings from a dried Mullein stalk.  Both of these items are incredibly useful to a survivor.  This crude cutting tool can be used for a variety of other survival chores as well.

Making a signalling mirror from one layer of the screen was also very clever.

Leaving East Germany

16 Sep

A few notes, some rather amusing, from a bleak period of history. To my generation, the Berlin Wall, Checkpoint Charlie, and escapes from East Germany, were unpleasant reality as we were growing up, though thankfully only in the form of news from afar. The two best pieces of news that I ever saw were the first moon landing and the fall of the Berlin Wall.

This commentary from John Dornberg, published in February 1980 Popular Mechanics, accompanied an article about the epic escape of Peter Strelzyk and Gunter Wetzel (along with their families) by means of a secretly built hot-air balloon.

A hundred ways to beat the border

Anyone with a strong desire to leave East Germany is standing at the end of a long, long line. Successful emigres have used just about every means except rockets. Many have tunneled, and some have scuba-dived, under the border. One man, in 1966, built a mini-submarine that conveyed him, at 3 mph. from the East to the West German coast along the Baltic Sea. Others have rowed that route in rafts and dinghies,  and one woman swam it – over 40 grueling hours.

Over the years, several dozens – a few not even trained as pilots – have used small planes to fly over it. And in 1962 an entire family, using helpers on the other side, crossed the Berlin Wall from one building to another on a tightrope cable with a roller and suspended sling seat.

East Germans are often smuggled out aboard the trucks traveling on the East-West transit routes, They jump their country’s ships in neutral harbors or off friendly shores. They take advantage of the more relaxed rules in some other socialist countries, such as Yugoslavia, to escape while on vacation (although loved ones are often left behind, since the government discourages entire families from vacationing together – for obvious reasons).

Some have simply rammed through border fortifications with armor-plated trucks, buses and cars. And every year several dozens – no one really knows how – continue to make it across the mine-fields, past the tripwires and shrapnel guns, watchtowers and guards, through and over the fences on foot. Every land conveyance known to man has been used, from a tiny Isetta, rebuilt to hide one person under the seat, to a Cadillac, remodeled by a professional escape organization to stow one escapee between dashboard and firewall.

The “gentlemanly” way, though by no means less risky, has been to simply outwit the border guards with passport flim-flams, fake documents or a straight face.

Thus, in the mid-1960s, some 180 East Germans were spirited out disguised as foreign diplomats, riding in long, black limousines from a car-rental agency, and displaying impressive-looking, leather-covered documents, originally printed as membership cards in a fancy West Germany Playboy-type club called “Confederation Diplomatique.” The initials “CD,” embossed on the cards, were misread by East German frontier guards as diplomatic passports.

Four East Germans once passed through Berlin’s “Checkpoint Charlie” wearing homemade Russian officers’ uniforms and driving a Soviet-make car which they had painted regulation olive green. The East German guards actually saluted them as they left.

One East Berliner even managed to escape backward. A professional photographer, he hired several beautiful girls as models, took them to “Checkpoint Charlie” and told border officials he was on assignment from an East German magazine to take publicity pictures of the frontier arrangements, which are ballyhooed by Eastern propaganda as a “defensive measure against capitalist-imperialism.” He asked several of the guards to pose with the girls and, with his back to West Berlin, began taking scores of pictures, moving one or two steps backward – closer to freedom – with each shot until he was standing on the white demarcation line. He then turned and bolted into the arms of American MPs, who had been watching his antics with great amusement.

Beyond the stone markers and demarcation signs is a space (A) up to 100 meters wide, cleared of trees and shrubs. The common double row of barbed wire fence (B) with land mines between is currently being replaced, either by a double row of wire-mesh fencing (C) and mined strip, or by single wire mesh fence (D) 10 feet high with tripwire or remotely triggered shrapnel guns mounted at leg, midsection and head levels. Beyond fencing is a concrete trench (E) to trap vehicles attempting to ram their way out. Beyond that, a plowed security strip (F) 40 feet wide picks up all footprints. Back from the service and patrol road are old-style wooden guard towers (G), newer concrete tower command posts (H) and observation bunkers (I), plus leashed dogs on long wire runs. Even nearby villages (J) have their 10-foot-high walls and the border crossing checkpoint (K), up to three miles from the border, lies along a rear security line (L) with electronic, acoustical and tripwire sensing devices.

The Mauermuseum  which, at least by their own account, recorded the events of border crossings and tried to help, had some more amusing bits in their “143rd Press Conference” of 2005. source, or source (alternate pages German and English)

The large number of visitors encouraged us to look for new premises: on 14 June 1963 the “Haus am Checkpoint Charlie” was opened and became an island of freedom right next to the border. From here, through a small window, escape helpers could observe all movements at the border crossing; escapees were always welcome and supported, escape plans were worked out, and injustice in the GDR was always fought against.

Mauermuseum – “Museum Haus Am Checkpoint Charlie”

Because helping refugees with fake passports was also punishable by Western courts, due to “document forgery,” Albert Schütz, a restaurateur by profession, smuggled invented passports. Instead of “Corps Diplomatique,” the passport would read “CONFEDERATION DIPLOMATIQUE.” Or else he made up United Nations passports. Those travelling with these were treated especially politely, since the GDR wanted to be accepted into the UN.

Checkpoint Charlie also remembers the most original flight. A GDR citizen succeeded in reaching the final checkpoint unnoticed. He was an Austrian, so he said breathlessly to the officer. He had just received a telegram that his mother lay dying in West Berlin. He had forgotten his passport in the excitement. The inspector fetched another and then went into the checkpoint-house, in order to make inquiries. The “Austrian” now told the same story to the new inspector and guard, only this time that his mother was in East Berlin. “Do you think they’ll let me through without a passport?” The answer he got was pessimistic. “I live very close by, then I’d rather go back and get my passport,” he said, and was in West Berlin.

The Giggle Wrecker

For an amusing fictional take on crossing the wall, I recommend the short story “The Giggle Wrecker“, in the collection “Pieces of Modesty” by Peter O’Donnell.

The Minister frowned. ‘If he can be got from Moscow to Berlin, surely you can get him over the Wall? It’s only another hundred yards or so.’    ‘A very particular hundred yards, Minister. Okubo is Japanese, and only four feet ten inches high. In an Aryan country he couldn’t be more obvious if he carried a banner with his name on it. Getting him out would require a major operation. Worst of all, we’re not the only ones who know he’s in East Berlin. The KGB knows it, too.’

—————–

‘We go in from Sweden by air,’ Modesty said. ‘Willie is Herr Jorgensen, who runs a small antique and rare-book business in Gothenberg. I’m his secretary. I can’t show you what I’ll look like just now because I have to dye my hair, but I’ll be equally convincing.’

‘We have got away with it for the last five years,’ Willie said in his rather stilted Jorgensen voice, and took out a packet of Swedish cigarettes. Tarrant looked at Modesty. She said, ‘We’ve made a ten- or twelve-day trip to East Berlin from Sweden every year for the last five. The antique business in Gothenberg is quite genuine and belongs to us.’

She gave a little shrug. ‘We began it a year or two before we retired from crime. It seemed a useful provision, to see what went on behind the Curtain and to establish credible identities there. We kept it up because it seemed a pity to let the thing lapse. The East Berlin police have Herr Jorgensen and Froken Osslund on record. We’ve been tailed and bugged and checked and politely questioned. They’ve given up tailing us now. We know that, because we always know if we’re being tailed. They may still bug our rooms. We never bother to check, because even if the rooms were clean there might be three bugs in each when we got back from a trip. So when we talk in our rooms, we talk in character.’