February 15, 2014

Lightbox for airbrushing

Projecting images to trace is inaccurate, at least when using an old fashioned analog projector; the lamp gets hot and expands the photo or print. It leads to incorrect positioning of eyes, nose, mouth and other parts of the human face. Digital projectors are less inaccurate, but still leave pencil lines on the airbrush that must be oversprayed or removed in order not to disturb the final product.

Click to see larger image - 3D rendering

This problem can be solved by using a lightbox, which is basically a traditional drawing table on which a (wooden) frame is built, in which lamps are placed. Preferably LED tube lights that do not emit a lot of heat. On top of the frame a glass plate is placed in an (aluminum) profile that is screwed to the frame. On this plate a print or photo is taped to the surface on which the portrait is to be sprayed. Taping the print / photo and airbrush paper or canvas together, makes it possible to work on several portraits at the same time. Simply replace one with the other to work on a different portrait.

Lightbox assembled - 3D rendering

In the image below the lightbox is shown with the LED tubes still turned off. The area around the portrait is covered with opaque carton to prevent light from the LED tubes to annoyingly shine directly on to the artist's face. The print / working surface combination will show clearly without light distracting or blinding the airbrusher.

LEDs turned off

When the LEDS are switched on it looks like in the image below. A sharp image of the print or photo shines through the airbrush paper or canvas. Since the material of the reference image and the working surface are taped together, there is no risk of parts of the face becoming misplaced, relative to each other. The eyes, nose, mouth and other parts show more clearly than in a pencil tracing and are always in the correct position.

LEDs switched on

On top of the lightbox I mounted a separate LED tubelight that allows me to exactly see what I have sprayed when the LED lights in the lightbox are switched off. The switch of the LEDS in the lightbox is mounted on the left side of the lightbox frame, which allows me to turn the LEDS on or off whenever I need to check how far I have progressed with the portrait. The location of the switch is indicated with a white arrow in the photograph below. It is a lamp's foot-switch originally that just needs tapping to alternate between on and off.

LED light switch

This technique works with paper and canvas, even when the canvas is still in its frame. Just make sure the reference image is positioned flush against the back of the framed canvas and the image will show through the canvas.

On the right side of the wooden lightbox frame I mounted the clamps for the airbrushes and a spray pot in which the airbrush can be placed when I need to take a break. On the wall to the left of the lightbox I placed an other tubelight on the same height as the lighbox, so that I can use that as well to simultaneously light the portrait while the LEDS inside the lightbox are still on. The light coming from the left caresses the surface I work on in a sharp angle, preventing my hand and airbrush to cast shadows on the surface which would hinder me in seeing the result of my spraying.

The wood were left over pieces from an other project in the house, the glass plate was second hand and cost me 7 Euro, The LED tubes inside the lightbox cost me 50 Euro and the aluminum profiles that support the glass plate cost a few Euro, which makes the total cost of the lightbox below 100 Euro.

Update February 18: On the Airbrushforum.org Iceman asked if the technique would work with T-shirts as well. It does actually, but I find it more convenient to tape the reference image to an LED-panel and pull the T-shirt over that, making sure the cloth is pressed against the reference image. It works well with white tees - the image shimmering through is quite clear and airbrushing this way leaves no pencil traces on the T-shirt. I have an LED panel that has a remote control dimmer, which allows to choose the required amount of light. LED panels, that come in many different sizes, can be purchased quite cheap after doing some research on the web.

Below is an image of the panel with (an unclear) reference image in front of it.

Reference image on LED panel

Then an image of a T-shirt pulled over it; note the tee is not ironed (...) and hence not laying well against the reference image.

Wrinkled T-shirt over panel and image

Below is the image of the set-up with the LEDs switched on.

And now with LEDs switched on

It is probably a good idea to use a sharper reference image, iron the tee and press it evenly against the reference image (perhaps by making a small frame that fits inside the frame of the LED panel or by taping the reference image on to a glass plate that fits inside the panel's frame), then you will have a clear enough image showing all detail necessary for a good airbrush.