PhotoProjector Glossary of Terms

2D Image
A flat ordinary image with no depth information. Example: a normal photograph.

3D Image
An image containing depth information which can be extracted by the human brain as the image is arranged to isolate Left-eye, Right-eye information by one of a series of methods: lenticular screen, hologram, anaglyph, cross-eyed, parallel-eyed, stereogram, ChromaDepth.

2D to 3D Process
The method of converting a single flat 2D image into a 3D image - normally by creating the non-existent depth information and adding it to the 2D image. Several methods can be employed: grey-scale depth map, shifting red/cyan channel information.


The process of align the image data strips with the micro-lenses in the Lenticular Screen.

Alignment Marks
A series of fine lines printed around the border of your image to assist in aligning the Lenticular Screen to the final Interlaced Image.

Viewer can perceive depth without artificial aid like 3D glasses or Lenticular Screen.

An autostereoscopic image, for example a cross-eyed 3D pair of images.

Banding may be commonly caused in an image by partially blocked inkjets. If Banding appears in your Lenticular Image only when viewed under the Lenticular Screen, it is caused by incorrect Interpolation either when sizing your images with your image editor or when setting the Print Parameters in PhotoProjector. Try 'Bilinear Interpolation' to avoid banding issues!

The right Interpolation setting to use is 'Bilinear' and not 'By neighbor' if you wish to avoid banding! Also see Moiré!

Two eyed vision. Human being have binocular vision. The brain perceives depth information by comparing the image in the left eye with the image from the right.

Ghosting in a 3D or Flip image caused by the right and left eyes seeing information in the image aimed at the other eye. Both eyes see left and right channel information instead of each channel being isolated for the left or the right eye. If cross-talk or ghosting is severe, the 3D, Flip, or animation effect is reduced or breaks down completely.

Depth Cues
The human brain uses several cues to perceive depth (3D) information. The strongest one is binocular vision but we also use light-level - where things further away become less distinct and hazy, size - where objects loser to us appear larger, perspective - where objects appear to recede along lines converging to a vanishing point, and shadows - both their perspectives and intensity.

Flat 3D or Cardboarding
A process where images are cut and put into layers for 3D or Flip image creation. Each flat picture is seen in the final image at a different depth but because there is no depth information in each flat image, the overall effect is like looking at cardboard cutouts. Not true Stereo-3D!

Focal Point
The point or position where a lens can accurately focus all the parallel rays of light.

Focal Length
The distance between a lens and the focal point for that lens.

The human brain automatically fuses information from Left and Right channels (eyes) and creates depth information from the parallax. When we create 3D, we fool the brain into recreating the depth information.

The bigger the parallax, (distance between left and right views in a 3D image) the greater the 3D effect. Every person will have different parallax limitations so if we increase the parallax too much - thus making a hyperstereo effect too much stereo - some people will be unable to fuse the information together in their brain to see a 3D image!

Image Resolution and Printer Resolution
Printed Images are made up of tiny points of colour. The resolution of the image defines the amount of data (dots) used to describe the image. The more dots used (if kept to the same micro-size) - the higher the definition and accuracy of the image. The Image resolution is quoted as Dots Per Inch (DPI) and images used on your computer will normally range from 72DPI (for viewing on a computer monitor) up to 4880DPI for printing on a high-end printer.

Typical values for images are 300dpi, 600dpi, 1200 dpi or 360dpi, 720dpi, 1440dpi.

More dots can be given to an image by increasing its size but this is only making the dots bigger and does not impart any addition resolution to an image.

Printers for home and semi-professional use are normally ink-jet printers (best for photographic images) and their DPI printing resolution varies according to the price, brand, and cost of the printer.

Epson Printers use a print resolution defined in multiples of 360dpi, thus their printers have resolutions of 360, 720,1440, 2880, DPI etc.,

Canon, HP, and Lexmark printers use a print resolution defined in multiples of 300dpi, thus their printers have resolutions of 300, 600, 1200, 2400, 4800 DPI etc.,

The Printer resolution is across the page and the vertical resolution is typically 50% of the horizontal resolution.

Interlacing (sometimes referred to as weaving)
The process (normally done by a computer and interlacing software) of combining a series of images into a single image for printing and viewing under a Lenticular Screen. Each image in the series is scanned by the software and strips of image data are taken from each image and 'laced' together to form a final image. The strips of image data are arranged so they align precisely with the Lenticular Lenses in the Lenticular Screen. PhotoProjector is an interlacing software program.

Interpolation (sometimes called resampling) is an imaging method to increase (or decrease) the number of pixels in a digital image. Virtually all image editing software supports one or more methods of interpolation. How smoothly images are enlarged without introducing jaggies depends on the sophistication of the algorithm.
Common Interpolation methods are: by neighbor, bicubic, bilinear!

Key Plane or Zero Parallax Plane
The point or layer in a 3D image where no depth is perceived because both the left and right eye receive the same information. Try holding your hand in front of your eyes about 6 inches away. Shut left-eye, open it, shut right-eye open it and keep repeating whilst moving hand slowly forward or backward. The point where no change in the viewing of your hand is perceived by left or right eye is the zero parallax plane or 'key plane' for your eye parallax.

Key Subject
Often the object of most interest positioned on the key plane or zero parallax.
Lens Pitch
A single cylindrical plano-convex lens is called a Lenticule. The width of the Lenticule is called the Lens Pitch and is normally expressed as both a decimal value, e.g. 0.5070mm and as a Lens Per Inch Value, e.g. 50LPI. Every Lenticular Screen will have a lens pitch quoted in Lines Per Inch.

A single cylindrical plano-convex lens.

Lenticular Lens or Lenticular Screen

An array of lenticules (see above) normally constructed on a PVC or Acrylic transparent material with good optical properties. By arranging strips of image data to align precisely with each lens in the sheet, a number of effects can be achieved:-

Lenticular Effects

Two images or more (up to 5 normally) can be interlaced so that viewing the final image through a lenticular sheet creates the effect of see the images magically transform n an instant from one to the other and back again by wiggling the sheet.

Two or more images (normally at least 4) interlaced so that the final image appears to have depth information when viewed through a lenticular screen, The original images would have been photographed from equal distances in a semi-circle around the subject representing a number of views.

Motion or Animation
Three or more images (can be up to many 20, 30, etc.) interlaced together so that when the final interlaced image is viewed under a lenticular screen, an animation or very short video sequence is observed. Normally used with very high LPI screens. (Typically 100LPI for movie!).

Two key images are used as first and last view with images in the in-between views made up of bits of both images merged together. This gives the effect of one subject (first view) changing into the other subject (last view) as if by changing shape magically, e.g. a cat turning into a crouching human.

These four basic effects can be combined by people experienced with Lenticular Imaging and creation.

An interference pattern observed when viewing an image under a Lenticular Screen as a result of harmonic frequencies between the LPI of the screen, the actual image elements, and the DPI and interpolation used in image editors and printers. Can be reduced by rotating and image to an optimum angle in PhotoProjector and printing it rotated. Also see 'Banding'.

Commonly used to describe the effect in our brain caused by the displacement between our two eyes. We have both horizontal and vertical parallax but we normally view things standing up and therefore rely mostly on horizontal parallax to extract depth information. When creating 3D we recreate a horizontal parallax equal or slighter greater than that of our eyes, and eliminate any vertical parallax to avoid destroying the 3D effect or making us uncomfortable when viewing the 3D image.

The Horizontal Parallax can be divided into three types:-

Positive Parallax
Where elements of the 3D image appear as inside the front plane. (like inside a 3D box).

Negative Parallax
Where image elements appear to be coming out in front of the front plane, like a hologram, outside of the 3D box.

Zero Plane Parallax
Where the image elements appear to sit on the front plane or screen in front of Positive Parallax elements and behind Negative Parallax elements.

When aligning the Lenticular Screen against the final Interlaced image, it important to determine the correct start lenticule for the flip or 3D image to present the right images in the right sequence or phase!

See Lens Pitch!

Pitch Test
It is critical to know how your printer prints ink on the paper and at what frequency of dots. A Pitch test is used before you try and produce any final Lenticular Image as a test of the way the LPI (lens per inch) of your screen needs to be re-interpreted in a way your printer can produce dots of ink aligned to where the physical lenses are in the screen.

A program called PitchTest is included with PhotoProjector for you to perform Pitch Tests on your printer. Accurate and Precise Pitch testing is critical in producing good Lenticular Images!

Pseudo Stereo
If the left/right eye image information is reversed (accidentally) the viewer perceives a false 3D effect which results in a feeling of being uncomfortable and dizzy. A small degree of pseudo-stereoscopic effect is often apparent in Lenticular 3D unless more views are incorporated to reduce the pseudo-stereoscopic effect.

Registration Lines
See Alignment Marks!

Viewing Angle
The amount in degrees of the viewer's movement with regard to the Lenticular screen and image before the images start repeating: the limitation of movement determined by the Viewing Angle of the Lenticule.

Viewing Distance
The distance between the viewer and the Lenticular screen where the 3D or Flip effect is designed to work best. Moving forward or backward of this distance gradually decreases the effect until it can no longer be observed.