Archive for the ‘Uncategorized’ Category

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Homemade Scaling Caliper for Drawing

July 10, 2017

I was browsing around on the internet this morning looking at drawing tools, and I stumbled across a youtube video of a fellow making a proportional drawing caliper. I’ve used these before, but lost the one I had bought some time ago. This sounded like a good project to fuss around with.

A drawing caliper is a measuring device made of two crossing sticks that allows you to scale up a measured distance depending on where you attach their intersection point. For example, if you set the small end to be 1 inch apart, with the center screw set to 2X, the points at the other end will be 2 inches apart. As long as that intersecting point stays the same, all your measurements will have the same proportion.

There are commercial calipers you can buy, such as this one from AccuraSee, but the one in Jen’s video looked pretty easy to make, and it was; however, I discovered a problem with three of the hole placements.

I decided to make mine out of two strips of balsa wood (3/32″ thick), being easy to cut and shape and not too flimsy. A 6/32″ screw and wingnut holds the pieces together. I printed out Jen’s diagram that he linked to on the video, and used that as a template for the balsa (1″ wide, 9″ long.) I drilled 5 holes according to his diagram, and tested the scaling by lining up the two ends with two rulers. The 1:1 scale in the center was easy to test since it’s in the direct center of the 9 inch strip. Hole #2 also measured out correctly by scaling up 1 inch to 2 inches on the other end, as you can see above. There was a problem, however, with the three other holes not being placed correctly. The 3rd hole should have read 3 inches, but instead I got 3 5/8 inches. hole #4 was 4 7/16, and hole #5 was 5 9/16.

I needed to make a new caliper with those three holes in different spots, and to do that I cut a slot between the three holes with this opening moved slightly forward (towards hole #2.) That way I can adjust the placement of the screw to figure out the new location. Doing this, I discovered hole #3 needed to move 1mm in Jen’s diagram, hole #4 moves 3mm, and hole #5 moves 4mm. Just that tiny adjustment made a huge difference on the other end.

I made marks on the balsa strip where the new holes needed to be, and cut and shaped two new strips of balsa. Now the calipers scale correctly in measurements of 1:1 up to 1:5. Below is Jen’s diagram that I’ve marked up with red lines showing the new placements. You can print this out, and see for yourself if it works to your liking. Balsa doesn’t drill very well, so I may make a new one later out of stronger wood, like oak.

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Alphons Mucha “The Slav Epic” Paintings

October 24, 2016

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These are a few high resolution photos from a set that my friend, Jim Vadeboncoeur Jr., took recently on his trip to Prague. They are three of a group of twenty paintings made by Alphons Mucha, called the Slav Epic.

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The paintings are huge canvases, reaching up to about 20 feet wide. The medium is described as egg tempera mixed with oil, which is also known as “tempera grassa.” This medium works best with the technique he used to apply the paint.

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One of the surprising revelations to me from these was how he painted large gradient areas as dabs of broken color. In reproductions I have seen of them, I’d always assumed that to be the texture of the paint, but the paint is actually quite thin. Instead he mixed the different shades and tones by hand, and applied them as thin brush strokes of dappled paint, most notable in the large skies. Coincidentally, I’ve found that when painting with an oil and casein emulsion, this is often the best way to work with the paint, rather than trying to blend large areas together. If you want it to look smoother, you can go back over it with a fatter oily layer.

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Jim photographed all of the paintings and placed them on his Facebook page. There you can also see close up details.

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Pocket Camera Found

November 30, 2008

While visiting my mother over the holdiay I spent some time digging through the closets hunting for my old Brownie still camera. She thought it was buried in the house somewhere, but apparantly she was confusing it with a Brownie Movie camera. No luck finding the Target 6-20, unfortunately. As a sort of consolation prize, I did uncover my Dad’s old Tele-Instamatic 608:

Instamatic Box

Instamatic Box


Camera and Flash

Camera and Flash

There was no film in the box, but that flip-flash has a few bulbs still unused. I’m curious to play with it. From what I understand the negatives are tiny, so I doubt it will offer that much for scanning purposes, and new film might be hard to find.

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Google Search Time-Life Photo Archive

November 20, 2008

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There’s a very useful search facility offered by Google Images of the Time-Life Photograph archive. It collects tons of photographs and engravings from the 1860s – 1970s. For example, using the images.google.com page enter a search phrase such as “dog source:life” to see all images tagged with “dog” in that archive, or specifically access the site at this location. The search results often give back “about 200” which makes me think there’s even more available. It’s a fun way to kill time.

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Free Stickers

November 4, 2008

Lookie what I got. How about you?

votesticker

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Scanning Black and White Negatives

October 27, 2008

I’m a big fan of black and white photography, and have tons of negatives from pictures I’ve taken over the years. Unfortunately, the prints I’ve had developed were not well made, and I don’t have a darkroom anymore, so scanning the slides is my best option.

There are special scanners you can buy that have a light-source built into the top of them for scanning slides or negatives. This device lights the negative as the scanner passes underneath. I’ve managed to rig up a similar system using a regular scanner and just a piece of Canson Pro Layout Marker paper without any special lighting. Color slides or negatives, by the way, won’t scan properly with this system, only black and white.

Scanner with negatives

Scanner with negatives

To make a print a light source is projected through the negative or slide onto emulsion-coated paper. The reason a regular scanner is not recommended for negatives is it doesn’t have that back lit source, so you’d only be scanning the front and not lighting the negative properly. You could just scan a print, but scanning the negative itself directly will give you better resolution.

What got me started on this project was reading an article about a guy who claimed to get decent scans using a florescent light and a plastic cover to light the negative as it was scanned. The white plastic sheet creates a diffused light through the back of the negative that gave him a proper scan, sort of like how a projection screen works. Unfortunately, my first test of that gave me poor results. The light was too bright. What needs to be controlled is the amount of light coming through the negative. Too much light will blind the scanner and give an image that is too bright. Not enough light will make it too dark.

After trying a series of different screens from paper to plastic and different light sources, I found what worked the best for me was the layout paper and dim daylight. The room was dimly lit by sunny daylight through closed blinds. I left the scanner top open, and placed the negative on the glass covered by the paper. After scanning you’ll need digital software that can invert the colors in the image. My scanner only goes up to 1200dpi, and if I reduce that to 300dpi I’ll get a good 4 x 6” print. If your scanner has a higher dpi that’s even better.

Scanned Negative

Scanned Negative

The Negative Inverted

The Negative Inverted

Another problem you need to be aware of is negatives curl from the emulsion that’s on them which causes them to not lie flat on the glass, and that gives a blurred scan. The paper alone won’t be enough to keep them flat. Slide scanners come with a plastic frame holder that keeps the negatives flat, and to do the same with this customized setup you need to press down the paper and negatives flat, but not block the light passing through or cast a shadow over the negative. I found that I could only manage to scan one or two strips at a time this way but that was okay with me. Also make sure that everything is clean and dust free.

If you want to scan in color, you’ll likely have to get a slide scanner. There are light tables that have special lamps in them for photography (I assume the scanners use these too,) and you could then shoot them on the table instead of scanning. Those tables aren’t cheap though, and you’d need a high quality camera with a macro lens, so a scanner may be more cost effective.