Input and the Principles of Film Scanning

Introduction

6 Minute Read

Analog film scanners.

In order to bring analog film imagery into the digital environment, it is necessary to utilize a scanner. There are various scanners, including drum scanners, flatbed scanners and film scanners that can be used to convert a negative, transparency, or reflective material into a digital image file.

The task of creating an optimum digital file from film or flat artwork is dependent on the quality of the original media, the quality of the scanning hardware as well as the how the scanner settings are used.

It is important to start with a high quality original.

Connection

Understanding and applying the technical concepts of Film Scanning will be helpful towards successfully completing the following upcoming assignments:

Ongoing Graded Image Making Assignments

Film Scanning Terms & Definitions

Resolution

The resolution of a scanner determines the level of detail recorded by the scanner and is often expressed and measured as dots per inch (dpi). However, the resolution of the scanner is specified by pixels per inch (ppi) and indicates how precisely the scanner can resolve an image.

Image quality improves with higher resolutions, but only up to a certain point, after which increasing resolution simply makes file sizes unmanageable without yielding any visible improvements to the image.

In determining resolution, the final outcome and use will dictate the number of pixels per inch (ppi – input) to the final resolution of dots per inch (dpi – output).

Recommended Resolutions

72 to 96 dpi for displays, including computer monitors, smartphones and tablets.

300 dpi for digital photographic prints

Bit Depth

The bit depth of an image is a mathematical description of the maximum levels of tone that are possible, expressed as a power of 2. The more levels the scanner is capable of capturing at the scanner stage, the more visual information there is to work with when optimizing the file.

For example, an 8-bit grayscale image is made up of 256 tones of gray. An RGB color image is made up of three-color channels. Each channel contains 8-bit grayscale information defining the amount of each color component of the full color image, making it a 24-bit color that can define up to 16.7 million possible colors. Utilizing higher bit depths (greater than 8-bits per channel/24 bit) will provide greater detail and smoother tonal gradations, but will also increase the file size.

Image Size, File Size and Output Size

The image size, file size and output size are determined by the number of pixels the image contains. The pixel dimensions are the surest way of defining the size of a digital file. This can be expressed by the following formula: number of pixels = physical dimension x (ppi) resolution.

In other words, there is a reciprocal relationship between pixel size, the physical dimensions and resolution.

For example, if a digital image has 3000 pixels along one axis, then the pixels could be output at 10 inches at a resolution of 300 ppi.

Altering the image size dimensions and resolution can be adjusted using the Image Size Dialog in Photoshop as well as with the Crop Tool

Image Resampling

Image resampling (adding or subtracting pixels from the file) is also known as interpolation and can be done in Camera Raw and/or Photoshop. While resampling down will not deteriorate a digital image file quality, “interpolating up” will describe the pixels with less definition that are soft. Recommended interpolation settings for printing:

Bicubic Interpolation provides better image quality by reading values horizontally, vertically, and diagonally to calculate a new pixel value.

Bicubic Smoother is considered the ideal choice for making an image larger.

Using the Flatbed Scanner

Epson Flatbed Scanner

Open cover of flatbed scanner and place reflective material face-down on scanner bed and close top or carefully remove accessory for scanning negatives/transparencies and place Film Negative Page or Film Adapter with negatives/transparencies Emulsion-Side Down (dull) / Base-Side Up (shiny) on scanner bed and close top.

Move Mouse Down to Desktop Dock and Click on Epson Scan 2 Icon to Open

Set Scanner Settings in Panel as follows:

Contact Sheet

NOTE: Set Document Source: Transparency Unit (with Film Area Guide)

NOTE: Set Resolution at 300 dpi for an Image that will be 8 x 10 inches @ 300 dpi.

Individual Negatives

Medium-Format

NOTE: Use 120 Film Holder, Place Film Emulsion-Down (Shiny-Side Up) and Align with White Triangles on Scanner

NOTE: Set Document Source: Transparency Unit

NOTE: Set Resolution at 2400 dpi for an Image that will be approximately 15 x 15 inches @ 300 dpi.

35mm

NOTE: Use 35mm Film Holder, Place Film Emulsion-Down (Shiny-Side Up) and Align with White Triangles on Scanner

NOTE: Set Document Source: Transparency Unit

NOTE: Set Resolution at 4800 dpi for an Image that will be approximately 13.5 x 21.75 inches @ 300 dpi.

NOTE: Rotation and/or Flipping (Right-Reading) of Image can be done in the Epson Preview Panel or later, in Photoshop.

NOTE: For Color Film, it will necessary to change the following settings:

- Film Type: Color Negative or Transparency
- Image Type: 24-bit Color

Saving Scan

Save As .TIF File