DIY Projector Screen
Why Make Your Own?
You get a new projector and quickly realize that using it against a white wall or hanging up a sheet of white fabric gives very disappointing results. Most available options are targeted at audiophiles with deep pockets who’re looking for the ultimate home-entertainment solution, and they require custom installation and so on.
There are cheaper, premade office-type ones (about $300), but the look and size might not be right for your space. You could get a special paint to put onto the wall, but that’d involve convincing your missus that a great, white patch on the wall is necessary. And that it really does match her scatter cushions.
How to Do It
Start with a piece of black-out cloth about three by two metres at a fabric shop. To make the roll-down mechanism, take a length of white PVC gutter downpipe (about 10cm diameter, so it will be quick to roll up), wrap the fabric once around it and sew it by hand along the length. It needs to be pulled tight along the pipe to stop wrinkles; put glue or concealed duct tape on each end to hold it. The fabric should be evenly supported across the whole length of the top.
Do this by rolling it once around a wooden baton and screw that into the wall. The fabric is strong enough for you to leave the edges as they are. To hold it rolled up, fashion a hook out of thick wire and sew a loop into the top of the screen.
What to Look Out For
LCD or DLP
As with the plasma versus LCD TV debate, in the world of projectors, liquid crystal display (LCD) vies for supremacy with digital light processing (DLP) technologies. DLP usually wins on video image quality, while LCDs run cooler and quieter – fan noise and heat generated can be a major downside of projectors versus televisions.
Resolution
As with flat-screen TVs, high definition is becoming entry level. Choose between 720p (1280 x 720) and 1080p (1920 x 1080) when you’re hooking up game consoles like the Xbox or playing Blu-Ray discs. Lower resolution such as DVD-quality (480p) means you lose definition quicker as you size up the projected image.
Brightness
The so-called ‘ANSI lumens’ number determines how well you’ll be able to see images when there’s a lot of ambient light. Under 1000 and, unless you draw the curtains or wait for nightfall, you’ll find the image too faint. Consider the projector’s primary use and where it will stand most of the time. Gamers will likely need it to be brighter, while those in for late-night screenings in the dark needn’t worry.
Aspect Ratio
For HD sources including game consoles and wide-screen broadcasts choose a native aspect ratio of 16:9 similar to HDTVs. 4:3 ratio projectors can also be adjusted to wide-screen.
Lamp Life
Most projectors lamps have a half-life (the period before it burns half as bright) of between 2000 to 4000 hours. Replacement prices vary greatly, but it is in the hundreds-of-dollars category. Take this cost into account if the projector is going to replace your primary television.
Contrast
Some high-end projectors are already coming out with contrast ratios of 75 000:1, which today’s TVs can’t even hope to match. Quoted figures can be manipulated, but usually the higher the better.
How to Screen Print – 5 Reasons You Should Use Photographic Emulsion to Make Your Stencil
If you are screen printing as a hobby, you may have tried several ways to create your stencil. One such way that has been popularized on the internet is the screen fill method. Essentially, the screen fill method involves painting an image on a screen using a filler that dries and becomes your stencil. Once the stencil is created, the screen is used the same way it always is with screen printing: it is positioned on the fabric, ink is loaded into the screen, and a squeegee is used to push the ink through it. Wherever the holes in the screen have not been painted over, the image is created.
While some may consider the screen fill method simple and inexpensive, there are several drawbacks:
1.It is extremely time consuming, in fact most demonstrations of this method involve low detail, simple art.
2.When you make a mistake painting the filler, it can be quite aggravating to try to fix.
3.It is tedious. It takes a long time and is painstaking.
4.If you want to reproduce the screen, you have to do the whole process over again, and it’ll never be exactly the same.
5.Line work and small type are pretty much out of the question. Imagine trying to paint the centers of letters like “e” and “a” or a long, straight line.
Fortunately, there is another method for creating stencils on screens that solves all five of the above problems, and it is also relatively inexpensive on a per screen basis: the photographic method using light sensitive emulsion.
Basically, the photographic method involves filling all the holes in the screen with photographic emulsion (also know as coating the screen). The emulsion is simply poured into a scoopcoater, and then dragged across the screen, creating a barrier about as thick as a few sheets of paper. When the coat dries, it’s ready for exposure.
Then a film is made with the desired image. The film has two parts to it, the light-blocking part and the transparent part. The film looks just like the final print will look, except it is black and clear.
The film acts as a light barrier when exposing the emulsion with light. Because the emulsion is light sensitive, it becomes water resistant when exposed. After exposure, the screen is rinsed, and the unexposed parts wash away. The image on the film becomes the stencil on the screen, allowing the ink to pass only where the image is. Films are commonly made of transparencies on a paper much like tracing paper, or on specially coated acetate sheets that can be printed with an ink jet printer.
While there are a few types of photographic emulsions, including capillary films, diazo, photopolymer, and dual cure, the light sensitive emulsion that is probably the most useful to the kind of printer that might consider the screen fill method is the dual cure emulsion. The reason why the dual cure is a suitable substitute is because someone who would use the screen fill method most likely is looking to do a short print run if they are using waterbased inks(less than 1000 pieces), they want to make a quality screen that can be recycled, and they want as few steps as possible to create the screen with as little expense.
Coating screens with photographic emulsion is a fairly quick and painless process once you get the hang of it. While there are some best practices and trouble-shooting tips that can shorten your learning curve, even without much experience most people pick it up quickly. The one main drawback of the photographic process is that you need a light source to expose your screen. Fortunately, with the right set-up, you have a large variety of choices including the sun.